Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

Conflicts:
	arch/sh/include/asm/Kbuild
	drivers/Makefile

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

17 files changed, 1804 insertions, 207 deletions

diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index d06083fdffbb..30f06e956bfb 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -47,6 +47,19 @@ config I2C_CHARDEV
           This support is also available as a module.  If so, the module 
           will be called i2c-dev.
 
+config I2C_MUX
+        tristate "I2C bus multiplexing support"
+        depends on EXPERIMENTAL
+        help
+          Say Y here if you want the I2C core to support the ability to
+          handle multiplexed I2C bus topologies, by presenting each
+          multiplexed segment as a I2C adapter.
+
+          This support is also available as a module.  If so, the module
+          will be called i2c-mux.
+
+source drivers/i2c/muxes/Kconfig
+
 config I2C_HELPER_AUTO
         bool "Autoselect pertinent helper modules"
         default y
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index a7d9b4be9bb3..c00fd66388f5 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -6,7 +6,8 @@ obj-$(CONFIG_I2C_BOARDINFO)	+= i2c-boardinfo.o
 obj-$(CONFIG_I2C)               += i2c-core.o
 obj-$(CONFIG_I2C_SMBUS)         += i2c-smbus.o
 obj-$(CONFIG_I2C_CHARDEV)       += i2c-dev.o
-obj-y                           += algos/ busses/
+obj-$(CONFIG_I2C_MUX)           += i2c-mux.o
+obj-y                           += algos/ busses/ muxes/
 
 ifeq ($(CONFIG_I2C_DEBUG_CORE),y)
 EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index bceafbfa7268..6539ac2907e9 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -448,6 +448,13 @@ config I2C_NOMADIK
           If you say yes to this option, support will be included for the
           I2C interface from ST-Ericsson's Nomadik and Ux500 architectures.
 
+config I2C_NUC900
+        tristate "NUC900 I2C Driver"
+        depends on ARCH_W90X900
+        help
+          Say Y here to include support for I2C controller in the
+          Winbond/Nuvoton NUC900 based System-on-Chip devices.
+
 config I2C_OCORES
         tristate "OpenCores I2C Controller"
         depends on EXPERIMENTAL
@@ -496,8 +503,8 @@ config I2C_PMCMSP
           will be called i2c-pmcmsp.
 
 config I2C_PNX
-        tristate "I2C bus support for Philips PNX targets"
-        depends on ARCH_PNX4008
+        tristate "I2C bus support for Philips PNX and NXP LPC targets"
+        depends on ARCH_PNX4008 || ARCH_LPC32XX
         help
           This driver supports the Philips IP3204 I2C IP block master and/or
           slave controller
@@ -521,12 +528,19 @@ config I2C_PXA_SLAVE
           is necessary for systems where the PXA may be a target on the
           I2C bus.
 
+config HAVE_S3C2410_I2C
+        bool
+        help
+          This will include I2C support for Samsung SoCs. If you want to
+          include I2C support for any machine, kindly select this in the
+          respective Kconfig file.
+
 config I2C_S3C2410
         tristate "S3C2410 I2C Driver"
-        depends on ARCH_S3C2410 || ARCH_S3C64XX
+        depends on HAVE_S3C2410_I2C
         help
           Say Y here to include support for I2C controller in the
-          Samsung S3C2410 based System-on-Chip devices.
+          Samsung SoCs.
 
 config I2C_S6000
         tristate "S6000 I2C support"
@@ -549,7 +563,7 @@ config I2C_SH7760
 
 config I2C_SH_MOBILE
         tristate "SuperH Mobile I2C Controller"
-        depends on SUPERH
+        depends on SUPERH || ARCH_SHMOBILE
         help
           If you say yes to this option, support will be included for the
           built-in I2C interface on the Renesas SH-Mobile processor.
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 936880bd1dc5..c3ef49230cba 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_IXP2000)	+= i2c-ixp2000.o
 obj-$(CONFIG_I2C_MPC)           += i2c-mpc.o
 obj-$(CONFIG_I2C_MV64XXX)       += i2c-mv64xxx.o
 obj-$(CONFIG_I2C_NOMADIK)       += i2c-nomadik.o
+obj-$(CONFIG_I2C_NUC900)        += i2c-nuc900.o
 obj-$(CONFIG_I2C_OCORES)        += i2c-ocores.o
 obj-$(CONFIG_I2C_OMAP)          += i2c-omap.o
 obj-$(CONFIG_I2C_PASEMI)        += i2c-pasemi.o
diff --git a/drivers/i2c/busses/i2c-cpm.c b/drivers/i2c/busses/i2c-cpm.c
index b02b4533651d..f7bd2613cecc 100644
--- a/drivers/i2c/busses/i2c-cpm.c
+++ b/drivers/i2c/busses/i2c-cpm.c
@@ -105,7 +105,7 @@ struct i2c_reg {
 
 struct cpm_i2c {
         char *base;
-        struct of_device *ofdev;
+        struct platform_device *ofdev;
         struct i2c_adapter adap;
         uint dp_addr;
         int version; /* CPM1=1, CPM2=2 */
@@ -428,7 +428,7 @@ static const struct i2c_adapter cpm_ops = {
 
 static int __devinit cpm_i2c_setup(struct cpm_i2c *cpm)
 {
-        struct of_device *ofdev = cpm->ofdev;
+        struct platform_device *ofdev = cpm->ofdev;
         const u32 *data;
         int len, ret, i;
         void __iomem *i2c_base;
@@ -634,7 +634,7 @@ static void cpm_i2c_shutdown(struct cpm_i2c *cpm)
                 cpm_muram_free(cpm->i2c_addr);
 }
 
-static int __devinit cpm_i2c_probe(struct of_device *ofdev,
+static int __devinit cpm_i2c_probe(struct platform_device *ofdev,
                          const struct of_device_id *match)
 {
         int result, len;
@@ -652,6 +652,7 @@ static int __devinit cpm_i2c_probe(struct of_device *ofdev,
         cpm->adap = cpm_ops;
         i2c_set_adapdata(&cpm->adap, cpm);
         cpm->adap.dev.parent = &ofdev->dev;
+        cpm->adap.dev.of_node = of_node_get(ofdev->dev.of_node);
 
         result = cpm_i2c_setup(cpm);
         if (result) {
@@ -676,11 +677,6 @@ static int __devinit cpm_i2c_probe(struct of_device *ofdev,
         dev_dbg(&ofdev->dev, "hw routines for %s registered.\n",
                 cpm->adap.name);
 
-        /*
-         * register OF I2C devices
-         */
-        of_register_i2c_devices(&cpm->adap, ofdev->dev.of_node);
-
         return 0;
 out_shut:
         cpm_i2c_shutdown(cpm);
@@ -691,7 +687,7 @@ out_free:
         return result;
 }
 
-static int __devexit cpm_i2c_remove(struct of_device *ofdev)
+static int __devexit cpm_i2c_remove(struct platform_device *ofdev)
 {
         struct cpm_i2c *cpm = dev_get_drvdata(&ofdev->dev);
 
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 4523364e6722..2222c87876b9 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -36,14 +36,16 @@
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/slab.h>
+#include <linux/cpufreq.h>
+#include <linux/gpio.h>
 
 #include <mach/hardware.h>
-
 #include <mach/i2c.h>
 
 /* ----- global defines ----------------------------------------------- */
 
 #define DAVINCI_I2C_TIMEOUT     (1*HZ)
+#define DAVINCI_I2C_MAX_TRIES   2
 #define I2C_DAVINCI_INTR_ALL    (DAVINCI_I2C_IMR_AAS | \
                                  DAVINCI_I2C_IMR_SCD | \
                                  DAVINCI_I2C_IMR_ARDY | \
@@ -72,37 +74,29 @@
 #define DAVINCI_I2C_IVR_NACK    0x02
 #define DAVINCI_I2C_IVR_AL      0x01
 
-#define DAVINCI_I2C_STR_BB      (1 << 12)
-#define DAVINCI_I2C_STR_RSFULL  (1 << 11)
-#define DAVINCI_I2C_STR_SCD     (1 << 5)
-#define DAVINCI_I2C_STR_ARDY    (1 << 2)
-#define DAVINCI_I2C_STR_NACK    (1 << 1)
-#define DAVINCI_I2C_STR_AL      (1 << 0)
-
-#define DAVINCI_I2C_MDR_NACK    (1 << 15)
-#define DAVINCI_I2C_MDR_STT     (1 << 13)
-#define DAVINCI_I2C_MDR_STP     (1 << 11)
-#define DAVINCI_I2C_MDR_MST     (1 << 10)
-#define DAVINCI_I2C_MDR_TRX     (1 << 9)
-#define DAVINCI_I2C_MDR_XA      (1 << 8)
-#define DAVINCI_I2C_MDR_RM      (1 << 7)
-#define DAVINCI_I2C_MDR_IRS     (1 << 5)
-
-#define DAVINCI_I2C_IMR_AAS     (1 << 6)
-#define DAVINCI_I2C_IMR_SCD     (1 << 5)
-#define DAVINCI_I2C_IMR_XRDY    (1 << 4)
-#define DAVINCI_I2C_IMR_RRDY    (1 << 3)
-#define DAVINCI_I2C_IMR_ARDY    (1 << 2)
-#define DAVINCI_I2C_IMR_NACK    (1 << 1)
-#define DAVINCI_I2C_IMR_AL      (1 << 0)
-
-#define MOD_REG_BIT(val, mask, set) do { \
-        if (set) { \
-                val |= mask; \
-        } else { \
-                val &= ~mask; \
-        } \
-} while (0)
+#define DAVINCI_I2C_STR_BB      BIT(12)
+#define DAVINCI_I2C_STR_RSFULL  BIT(11)
+#define DAVINCI_I2C_STR_SCD     BIT(5)
+#define DAVINCI_I2C_STR_ARDY    BIT(2)
+#define DAVINCI_I2C_STR_NACK    BIT(1)
+#define DAVINCI_I2C_STR_AL      BIT(0)
+
+#define DAVINCI_I2C_MDR_NACK    BIT(15)
+#define DAVINCI_I2C_MDR_STT     BIT(13)
+#define DAVINCI_I2C_MDR_STP     BIT(11)
+#define DAVINCI_I2C_MDR_MST     BIT(10)
+#define DAVINCI_I2C_MDR_TRX     BIT(9)
+#define DAVINCI_I2C_MDR_XA      BIT(8)
+#define DAVINCI_I2C_MDR_RM      BIT(7)
+#define DAVINCI_I2C_MDR_IRS     BIT(5)
+
+#define DAVINCI_I2C_IMR_AAS     BIT(6)
+#define DAVINCI_I2C_IMR_SCD     BIT(5)
+#define DAVINCI_I2C_IMR_XRDY    BIT(4)
+#define DAVINCI_I2C_IMR_RRDY    BIT(3)
+#define DAVINCI_I2C_IMR_ARDY    BIT(2)
+#define DAVINCI_I2C_IMR_NACK    BIT(1)
+#define DAVINCI_I2C_IMR_AL      BIT(0)
 
 struct davinci_i2c_dev {
         struct device           *dev;
@@ -113,8 +107,13 @@ struct davinci_i2c_dev {
         u8                      *buf;
         size_t                  buf_len;
         int                     irq;
+        int                     stop;
         u8                      terminate;
         struct i2c_adapter      adapter;
+#ifdef CONFIG_CPU_FREQ
+        struct completion       xfr_complete;
+        struct notifier_block   freq_transition;
+#endif
 };
 
 /* default platform data to use if not supplied in the platform_device */
@@ -134,12 +133,59 @@ static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
         return __raw_readw(i2c_dev->base + reg);
 }
 
-/*
- * This functions configures I2C and brings I2C out of reset.
- * This function is called during I2C init function. This function
- * also gets called if I2C encounters any errors.
+/* Generate a pulse on the i2c clock pin. */
+static void generic_i2c_clock_pulse(unsigned int scl_pin)
+{
+        u16 i;
+
+        if (scl_pin) {
+                /* Send high and low on the SCL line */
+                for (i = 0; i < 9; i++) {
+                        gpio_set_value(scl_pin, 0);
+                        udelay(20);
+                        gpio_set_value(scl_pin, 1);
+                        udelay(20);
+                }
+        }
+}
+
+/* This routine does i2c bus recovery as specified in the
+ * i2c protocol Rev. 03 section 3.16 titled "Bus clear"
  */
-static int i2c_davinci_init(struct davinci_i2c_dev *dev)
+static void i2c_recover_bus(struct davinci_i2c_dev *dev)
+{
+        u32 flag = 0;
+        struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
+
+        dev_err(dev->dev, "initiating i2c bus recovery\n");
+        /* Send NACK to the slave */
+        flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
+        flag |=  DAVINCI_I2C_MDR_NACK;
+        /* write the data into mode register */
+        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
+        if (pdata)
+                generic_i2c_clock_pulse(pdata->scl_pin);
+        /* Send STOP */
+        flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
+        flag |= DAVINCI_I2C_MDR_STP;
+        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
+}
+
+static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
+                                                                int val)
+{
+        u16 w;
+
+        w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
+        if (!val)       /* put I2C into reset */
+                w &= ~DAVINCI_I2C_MDR_IRS;
+        else            /* take I2C out of reset */
+                w |= DAVINCI_I2C_MDR_IRS;
+
+        davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
+}
+
+static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
 {
         struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
         u16 psc;
@@ -148,15 +194,6 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
         u32 clkh;
         u32 clkl;
         u32 input_clock = clk_get_rate(dev->clk);
-        u16 w;
-
-        if (!pdata)
-                pdata = &davinci_i2c_platform_data_default;
-
-        /* put I2C into reset */
-        w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-        MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
-        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 
         /* NOTE: I2C Clock divider programming info
          * As per I2C specs the following formulas provide prescaler
@@ -188,12 +225,32 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
 
+        dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
+}
+
+/*
+ * This function configures I2C and brings I2C out of reset.
+ * This function is called during I2C init function. This function
+ * also gets called if I2C encounters any errors.
+ */
+static int i2c_davinci_init(struct davinci_i2c_dev *dev)
+{
+        struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
+
+        if (!pdata)
+                pdata = &davinci_i2c_platform_data_default;
+
+        /* put I2C into reset */
+        davinci_i2c_reset_ctrl(dev, 0);
+
+        /* compute clock dividers */
+        i2c_davinci_calc_clk_dividers(dev);
+
         /* Respond at reserved "SMBus Host" slave address" (and zero);
          * we seem to have no option to not respond...
          */
         davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
 
-        dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
         dev_dbg(dev->dev, "PSC  = %d\n",
                 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
         dev_dbg(dev->dev, "CLKL = %d\n",
@@ -204,9 +261,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
                 pdata->bus_freq, pdata->bus_delay);
 
         /* Take the I2C module out of reset: */
-        w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-        MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
-        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
+        davinci_i2c_reset_ctrl(dev, 1);
 
         /* Enable interrupts */
         davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
@@ -221,14 +276,22 @@ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
                                          char allow_sleep)
 {
         unsigned long timeout;
+        static u16 to_cnt;
 
         timeout = jiffies + dev->adapter.timeout;
         while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
                & DAVINCI_I2C_STR_BB) {
-                if (time_after(jiffies, timeout)) {
-                        dev_warn(dev->dev,
-                                 "timeout waiting for bus ready\n");
-                        return -ETIMEDOUT;
+                if (to_cnt <= DAVINCI_I2C_MAX_TRIES) {
+                        if (time_after(jiffies, timeout)) {
+                                dev_warn(dev->dev,
+                                "timeout waiting for bus ready\n");
+                                to_cnt++;
+                                return -ETIMEDOUT;
+                        } else {
+                                to_cnt = 0;
+                                i2c_recover_bus(dev);
+                                i2c_davinci_init(dev);
+                        }
                 }
                 if (allow_sleep)
                         schedule_timeout(1);
@@ -250,9 +313,6 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
         u16 w;
         int r;
 
-        if (msg->len == 0)
-                return -EINVAL;
-
         if (!pdata)
                 pdata = &davinci_i2c_platform_data_default;
         /* Introduce a delay, required for some boards (e.g Davinci EVM) */
@@ -264,6 +324,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 
         dev->buf = msg->buf;
         dev->buf_len = msg->len;
+        dev->stop = stop;
 
         davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
 
@@ -281,23 +342,40 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
                 flag |= DAVINCI_I2C_MDR_TRX;
         if (stop)
                 flag |= DAVINCI_I2C_MDR_STP;
+        if (msg->len == 0) {
+                flag |= DAVINCI_I2C_MDR_RM;
+                flag &= ~DAVINCI_I2C_MDR_STP;
+        }
 
         /* Enable receive or transmit interrupts */
         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
         if (msg->flags & I2C_M_RD)
-                MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 1);
+                w |= DAVINCI_I2C_IMR_RRDY;
         else
-                MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
+                w |= DAVINCI_I2C_IMR_XRDY;
         davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
 
         dev->terminate = 0;
+
         /* write the data into mode register */
         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 
+        /*
+         * First byte should be set here, not after interrupt,
+         * because transmit-data-ready interrupt can come before
+         * NACK-interrupt during sending of previous message and
+         * ICDXR may have wrong data
+         */
+        if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
+                davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
+                dev->buf_len--;
+        }
+
         r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
                                                       dev->adapter.timeout);
         if (r == 0) {
                 dev_err(dev->dev, "controller timed out\n");
+                i2c_recover_bus(dev);
                 i2c_davinci_init(dev);
                 dev->buf_len = 0;
                 return -ETIMEDOUT;
@@ -334,7 +412,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
                         return msg->len;
                 if (stop) {
                         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-                        MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
+                        w |= DAVINCI_I2C_MDR_STP;
                         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
                 }
                 return -EREMOTEIO;
@@ -367,12 +445,17 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
                 if (ret < 0)
                         return ret;
         }
+
+#ifdef CONFIG_CPU_FREQ
+        complete(&dev->xfr_complete);
+#endif
+
         return num;
 }
 
 static u32 i2c_davinci_func(struct i2c_adapter *adap)
 {
-        return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }
 
 static void terminate_read(struct davinci_i2c_dev *dev)
@@ -431,6 +514,14 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
                 case DAVINCI_I2C_IVR_ARDY:
                         davinci_i2c_write_reg(dev,
                                 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
+                        if (((dev->buf_len == 0) && (dev->stop != 0)) ||
+                            (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
+                                w = davinci_i2c_read_reg(dev,
+                                                         DAVINCI_I2C_MDR_REG);
+                                w |= DAVINCI_I2C_MDR_STP;
+                                davinci_i2c_write_reg(dev,
+                                                      DAVINCI_I2C_MDR_REG, w);
+                        }
                         complete(&dev->cmd_complete);
                         break;
 
@@ -462,7 +553,7 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
 
                                 w = davinci_i2c_read_reg(dev,
                                                          DAVINCI_I2C_IMR_REG);
-                                MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 0);
+                                w &= ~DAVINCI_I2C_IMR_XRDY;
                                 davinci_i2c_write_reg(dev,
                                                       DAVINCI_I2C_IMR_REG,
                                                       w);
@@ -491,6 +582,48 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
         return count ? IRQ_HANDLED : IRQ_NONE;
 }
 
+#ifdef CONFIG_CPU_FREQ
+static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
+                                     unsigned long val, void *data)
+{
+        struct davinci_i2c_dev *dev;
+
+        dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
+        if (val == CPUFREQ_PRECHANGE) {
+                wait_for_completion(&dev->xfr_complete);
+                davinci_i2c_reset_ctrl(dev, 0);
+        } else if (val == CPUFREQ_POSTCHANGE) {
+                i2c_davinci_calc_clk_dividers(dev);
+                davinci_i2c_reset_ctrl(dev, 1);
+        }
+
+        return 0;
+}
+
+static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
+{
+        dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
+
+        return cpufreq_register_notifier(&dev->freq_transition,
+                                         CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
+{
+        cpufreq_unregister_notifier(&dev->freq_transition,
+                                    CPUFREQ_TRANSITION_NOTIFIER);
+}
+#else
+static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
+{
+        return 0;
+}
+
+static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
+{
+}
+#endif
+
 static struct i2c_algorithm i2c_davinci_algo = {
         .master_xfer    = i2c_davinci_xfer,
         .functionality  = i2c_davinci_func,
@@ -530,6 +663,9 @@ static int davinci_i2c_probe(struct platform_device *pdev)
         }
 
         init_completion(&dev->cmd_complete);
+#ifdef CONFIG_CPU_FREQ
+        init_completion(&dev->xfr_complete);
+#endif
         dev->dev = get_device(&pdev->dev);
         dev->irq = irq->start;
         platform_set_drvdata(pdev, dev);
@@ -541,7 +677,12 @@ static int davinci_i2c_probe(struct platform_device *pdev)
         }
         clk_enable(dev->clk);
 
-        dev->base = (void __iomem *)IO_ADDRESS(mem->start);
+        dev->base = ioremap(mem->start, resource_size(mem));
+        if (!dev->base) {
+                r = -EBUSY;
+                goto err_mem_ioremap;
+        }
+
         i2c_davinci_init(dev);
 
         r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
@@ -550,6 +691,12 @@ static int davinci_i2c_probe(struct platform_device *pdev)
                 goto err_unuse_clocks;
         }
 
+        r = i2c_davinci_cpufreq_register(dev);
+        if (r) {
+                dev_err(&pdev->dev, "failed to register cpufreq\n");
+                goto err_free_irq;
+        }
+
         adap = &dev->adapter;
         i2c_set_adapdata(adap, dev);
         adap->owner = THIS_MODULE;
@@ -571,6 +718,8 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 err_free_irq:
         free_irq(dev->irq, dev);
 err_unuse_clocks:
+        iounmap(dev->base);
+err_mem_ioremap:
         clk_disable(dev->clk);
         clk_put(dev->clk);
         dev->clk = NULL;
@@ -589,6 +738,8 @@ static int davinci_i2c_remove(struct platform_device *pdev)
         struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
         struct resource *mem;
 
+        i2c_davinci_cpufreq_deregister(dev);
+
         platform_set_drvdata(pdev, NULL);
         i2c_del_adapter(&dev->adapter);
         put_device(&pdev->dev);
@@ -599,6 +750,7 @@ static int davinci_i2c_remove(struct platform_device *pdev)
 
         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
         free_irq(IRQ_I2C, dev);
+        iounmap(dev->base);
         kfree(dev);
 
         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -606,6 +758,41 @@ static int davinci_i2c_remove(struct platform_device *pdev)
         return 0;
 }
 
+#ifdef CONFIG_PM
+static int davinci_i2c_suspend(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+
+        /* put I2C into reset */
+        davinci_i2c_reset_ctrl(i2c_dev, 0);
+        clk_disable(i2c_dev->clk);
+
+        return 0;
+}
+
+static int davinci_i2c_resume(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+
+        clk_enable(i2c_dev->clk);
+        /* take I2C out of reset */
+        davinci_i2c_reset_ctrl(i2c_dev, 1);
+
+        return 0;
+}
+
+static const struct dev_pm_ops davinci_i2c_pm = {
+        .suspend        = davinci_i2c_suspend,
+        .resume         = davinci_i2c_resume,
+};
+
+#define davinci_i2c_pm_ops (&davinci_i2c_pm)
+#else
+#define davinci_i2c_pm_ops NULL
+#endif
+
 /* work with hotplug and coldplug */
 MODULE_ALIAS("platform:i2c_davinci");
 
@@ -615,6 +802,7 @@ static struct platform_driver davinci_i2c_driver = {
         .driver         = {
                 .name   = "i2c_davinci",
                 .owner  = THIS_MODULE,
+                .pm     = davinci_i2c_pm_ops,
         },
 };
 
diff --git a/drivers/i2c/busses/i2c-ibm_iic.c b/drivers/i2c/busses/i2c-ibm_iic.c
index bf344135647a..43ca32fddde2 100644
--- a/drivers/i2c/busses/i2c-ibm_iic.c
+++ b/drivers/i2c/busses/i2c-ibm_iic.c
@@ -661,7 +661,7 @@ static inline u8 iic_clckdiv(unsigned int opb)
         return (u8)((opb + 9) / 10 - 1);
 }
 
-static int __devinit iic_request_irq(struct of_device *ofdev,
+static int __devinit iic_request_irq(struct platform_device *ofdev,
                                      struct ibm_iic_private *dev)
 {
         struct device_node *np = ofdev->dev.of_node;
@@ -692,7 +692,7 @@ static int __devinit iic_request_irq(struct of_device *ofdev,
 /*
  * Register single IIC interface
  */
-static int __devinit iic_probe(struct of_device *ofdev,
+static int __devinit iic_probe(struct platform_device *ofdev,
                                const struct of_device_id *match)
 {
         struct device_node *np = ofdev->dev.of_node;
@@ -745,6 +745,7 @@ static int __devinit iic_probe(struct of_device *ofdev,
         /* Register it with i2c layer */
         adap = &dev->adap;
         adap->dev.parent = &ofdev->dev;
+        adap->dev.of_node = of_node_get(np);
         strlcpy(adap->name, "IBM IIC", sizeof(adap->name));
         i2c_set_adapdata(adap, dev);
         adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
@@ -760,9 +761,6 @@ static int __devinit iic_probe(struct of_device *ofdev,
         dev_info(&ofdev->dev, "using %s mode\n",
                  dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
 
-        /* Now register all the child nodes */
-        of_register_i2c_devices(adap, np);
-
         return 0;
 
 error_cleanup:
@@ -782,7 +780,7 @@ error_cleanup:
 /*
  * Cleanup initialized IIC interface
  */
-static int __devexit iic_remove(struct of_device *ofdev)
+static int __devexit iic_remove(struct platform_device *ofdev)
 {
         struct ibm_iic_private *dev = dev_get_drvdata(&ofdev->dev);
 
diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index df00eb1f11f9..a1c419a716af 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -63,6 +63,7 @@ struct mpc_i2c {
         wait_queue_head_t queue;
         struct i2c_adapter adap;
         int irq;
+        u32 real_clk;
 };
 
 struct mpc_i2c_divider {
@@ -96,20 +97,23 @@ static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
 /* Sometimes 9th clock pulse isn't generated, and slave doesn't release
  * the bus, because it wants to send ACK.
  * Following sequence of enabling/disabling and sending start/stop generates
- * the pulse, so it's all OK.
+ * the 9 pulses, so it's all OK.
  */
 static void mpc_i2c_fixup(struct mpc_i2c *i2c)
 {
-        writeccr(i2c, 0);
-        udelay(30);
-        writeccr(i2c, CCR_MEN);
-        udelay(30);
-        writeccr(i2c, CCR_MSTA | CCR_MTX);
-        udelay(30);
-        writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN);
-        udelay(30);
-        writeccr(i2c, CCR_MEN);
-        udelay(30);
+        int k;
+        u32 delay_val = 1000000 / i2c->real_clk + 1;
+
+        if (delay_val < 2)
+                delay_val = 2;
+
+        for (k = 9; k; k--) {
+                writeccr(i2c, 0);
+                writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN);
+                udelay(delay_val);
+                writeccr(i2c, CCR_MEN);
+                udelay(delay_val << 1);
+        }
 }
 
 static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
@@ -190,15 +194,18 @@ static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] __devinitconst = {
 };
 
 static int __devinit mpc_i2c_get_fdr_52xx(struct device_node *node, u32 clock,
-                                          int prescaler)
+                                          int prescaler, u32 *real_clk)
 {
         const struct mpc_i2c_divider *div = NULL;
         unsigned int pvr = mfspr(SPRN_PVR);
         u32 divider;
         int i;
 
-        if (clock == MPC_I2C_CLOCK_LEGACY)
+        if (clock == MPC_I2C_CLOCK_LEGACY) {
+                /* see below - default fdr = 0x3f -> div = 2048 */
+                *real_clk = mpc5xxx_get_bus_frequency(node) / 2048;
                 return -EINVAL;
+        }
 
         /* Determine divider value */
         divider = mpc5xxx_get_bus_frequency(node) / clock;
@@ -216,7 +223,8 @@ static int __devinit mpc_i2c_get_fdr_52xx(struct device_node *node, u32 clock,
                         break;
         }
 
-        return div ? (int)div->fdr : -EINVAL;
+        *real_clk = mpc5xxx_get_bus_frequency(node) / div->divider;
+        return (int)div->fdr;
 }
 
 static void __devinit mpc_i2c_setup_52xx(struct device_node *node,
@@ -231,13 +239,14 @@ static void __devinit mpc_i2c_setup_52xx(struct device_node *node,
                 return;
         }
 
-        ret = mpc_i2c_get_fdr_52xx(node, clock, prescaler);
+        ret = mpc_i2c_get_fdr_52xx(node, clock, prescaler, &i2c->real_clk);
         fdr = (ret >= 0) ? ret : 0x3f; /* backward compatibility */
 
         writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
 
         if (ret >= 0)
-                dev_info(i2c->dev, "clock %d Hz (fdr=%d)\n", clock, fdr);
+                dev_info(i2c->dev, "clock %u Hz (fdr=%d)\n", i2c->real_clk,
+                         fdr);
 }
 #else /* !(CONFIG_PPC_MPC52xx || CONFIG_PPC_MPC512x) */
 static void __devinit mpc_i2c_setup_52xx(struct device_node *node,
@@ -334,14 +343,17 @@ static u32 __devinit mpc_i2c_get_sec_cfg_8xxx(void)
 }
 
 static int __devinit mpc_i2c_get_fdr_8xxx(struct device_node *node, u32 clock,
-                                          u32 prescaler)
+                                          u32 prescaler, u32 *real_clk)
 {
         const struct mpc_i2c_divider *div = NULL;
         u32 divider;
         int i;
 
-        if (clock == MPC_I2C_CLOCK_LEGACY)
+        if (clock == MPC_I2C_CLOCK_LEGACY) {
+                /* see below - default fdr = 0x1031 -> div = 16 * 3072 */
+                *real_clk = fsl_get_sys_freq() / prescaler / (16 * 3072);
                 return -EINVAL;
+        }
 
         /* Determine proper divider value */
         if (of_device_is_compatible(node, "fsl,mpc8544-i2c"))
@@ -364,6 +376,7 @@ static int __devinit mpc_i2c_get_fdr_8xxx(struct device_node *node, u32 clock,
                         break;
         }
 
+        *real_clk = fsl_get_sys_freq() / prescaler / div->divider;
         return div ? (int)div->fdr : -EINVAL;
 }
 
@@ -380,7 +393,7 @@ static void __devinit mpc_i2c_setup_8xxx(struct device_node *node,
                 return;
         }
 
-        ret = mpc_i2c_get_fdr_8xxx(node, clock, prescaler);
+        ret = mpc_i2c_get_fdr_8xxx(node, clock, prescaler, &i2c->real_clk);
         fdr = (ret >= 0) ? ret : 0x1031; /* backward compatibility */
 
         writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
@@ -388,7 +401,7 @@ static void __devinit mpc_i2c_setup_8xxx(struct device_node *node,
 
         if (ret >= 0)
                 dev_info(i2c->dev, "clock %d Hz (dfsrr=%d fdr=%d)\n",
-                         clock, fdr >> 8, fdr & 0xff);
+                         i2c->real_clk, fdr >> 8, fdr & 0xff);
 }
 
 #else /* !CONFIG_FSL_SOC */
@@ -500,10 +513,14 @@ static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
                         return -EINTR;
                 }
                 if (time_after(jiffies, orig_jiffies + HZ)) {
+                        u8 status = readb(i2c->base + MPC_I2C_SR);
+
                         dev_dbg(i2c->dev, "timeout\n");
-                        if (readb(i2c->base + MPC_I2C_SR) ==
-                            (CSR_MCF | CSR_MBB | CSR_RXAK))
+                        if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) {
+                                writeb(status & ~CSR_MAL,
+                                       i2c->base + MPC_I2C_SR);
                                 mpc_i2c_fixup(i2c);
+                        }
                         return -EIO;
                 }
                 schedule();
@@ -543,7 +560,7 @@ static struct i2c_adapter mpc_ops = {
         .timeout = HZ,
 };
 
-static int __devinit fsl_i2c_probe(struct of_device *op,
+static int __devinit fsl_i2c_probe(struct platform_device *op,
                                    const struct of_device_id *match)
 {
         struct mpc_i2c *i2c;
@@ -595,18 +612,26 @@ static int __devinit fsl_i2c_probe(struct of_device *op,
                         mpc_i2c_setup_8xxx(op->dev.of_node, i2c, clock, 0);
         }
 
+        prop = of_get_property(op->dev.of_node, "fsl,timeout", &plen);
+        if (prop && plen == sizeof(u32)) {
+                mpc_ops.timeout = *prop * HZ / 1000000;
+                if (mpc_ops.timeout < 5)
+                        mpc_ops.timeout = 5;
+        }
+        dev_info(i2c->dev, "timeout %u us\n", mpc_ops.timeout * 1000000 / HZ);
+
         dev_set_drvdata(&op->dev, i2c);
 
         i2c->adap = mpc_ops;
         i2c_set_adapdata(&i2c->adap, i2c);
         i2c->adap.dev.parent = &op->dev;
+        i2c->adap.dev.of_node = of_node_get(op->dev.of_node);
 
         result = i2c_add_adapter(&i2c->adap);
         if (result < 0) {
                 dev_err(i2c->dev, "failed to add adapter\n");
                 goto fail_add;
         }
-        of_register_i2c_devices(&i2c->adap, op->dev.of_node);
 
         return result;
 
@@ -621,7 +646,7 @@ static int __devinit fsl_i2c_probe(struct of_device *op,
         return result;
 };
 
-static int __devexit fsl_i2c_remove(struct of_device *op)
+static int __devexit fsl_i2c_remove(struct platform_device *op)
 {
         struct mpc_i2c *i2c = dev_get_drvdata(&op->dev);
 
diff --git a/drivers/i2c/busses/i2c-nuc900.c b/drivers/i2c/busses/i2c-nuc900.c
new file mode 100644
index 000000000000..92d770d7bbc2
--- /dev/null
+++ b/drivers/i2c/busses/i2c-nuc900.c
@@ -0,0 +1,709 @@
+/*
+ * linux/drivers/i2c/busses/i2c-nuc900.c
+ *
+ * Copyright (c) 2010 Nuvoton technology corporation.
+ *
+ * This driver based on S3C2410 I2C driver of Ben Dooks <ben-Y5A6D6n0/KfQXOPxS62xeg@public.gmane.org>.
+ * Written by Wan ZongShun <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation;version 2 of the License.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include <linux/i2c.h>
+#include <linux/i2c-id.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+
+#include <mach/mfp.h>
+#include <mach/i2c.h>
+
+/* nuc900 i2c registers offset */
+
+#define CSR             0x00
+#define DIVIDER         0x04
+#define CMDR            0x08
+#define SWR             0x0C
+#define RXR             0x10
+#define TXR             0x14
+
+/* nuc900 i2c CSR register bits */
+
+#define IRQEN           0x003
+#define I2CBUSY         0x400
+#define I2CSTART        0x018
+#define IRQFLAG         0x004
+#define ARBIT_LOST      0x200
+#define SLAVE_ACK       0x800
+
+/* nuc900 i2c CMDR register bits */
+
+#define I2C_CMD_START   0x10
+#define I2C_CMD_STOP    0x08
+#define I2C_CMD_READ    0x04
+#define I2C_CMD_WRITE   0x02
+#define I2C_CMD_NACK    0x01
+
+/* i2c controller state */
+
+enum nuc900_i2c_state {
+        STATE_IDLE,
+        STATE_START,
+        STATE_READ,
+        STATE_WRITE,
+        STATE_STOP
+};
+
+/* i2c controller private data */
+
+struct nuc900_i2c {
+        spinlock_t              lock;
+        wait_queue_head_t       wait;
+
+        struct i2c_msg          *msg;
+        unsigned int            msg_num;
+        unsigned int            msg_idx;
+        unsigned int            msg_ptr;
+        unsigned int            irq;
+
+        enum nuc900_i2c_state   state;
+
+        void __iomem            *regs;
+        struct clk              *clk;
+        struct device           *dev;
+        struct resource         *ioarea;
+        struct i2c_adapter      adap;
+};
+
+/* nuc900_i2c_master_complete
+ *
+ * complete the message and wake up the caller, using the given return code,
+ * or zero to mean ok.
+*/
+
+static inline void nuc900_i2c_master_complete(struct nuc900_i2c *i2c, int ret)
+{
+        dev_dbg(i2c->dev, "master_complete %d\n", ret);
+
+        i2c->msg_ptr = 0;
+        i2c->msg = NULL;
+        i2c->msg_idx++;
+        i2c->msg_num = 0;
+        if (ret)
+                i2c->msg_idx = ret;
+
+        wake_up(&i2c->wait);
+}
+
+/* irq enable/disable functions */
+
+static inline void nuc900_i2c_disable_irq(struct nuc900_i2c *i2c)
+{
+        unsigned long tmp;
+
+        tmp = readl(i2c->regs + CSR);
+        writel(tmp & ~IRQEN, i2c->regs + CSR);
+}
+
+static inline void nuc900_i2c_enable_irq(struct nuc900_i2c *i2c)
+{
+        unsigned long tmp;
+
+        tmp = readl(i2c->regs + CSR);
+        writel(tmp | IRQEN, i2c->regs + CSR);
+}
+
+
+/* nuc900_i2c_message_start
+ *
+ * put the start of a message onto the bus
+*/
+
+static void nuc900_i2c_message_start(struct nuc900_i2c *i2c,
+                                      struct i2c_msg *msg)
+{
+        unsigned int addr = (msg->addr & 0x7f) << 1;
+
+        if (msg->flags & I2C_M_RD)
+                addr |= 0x1;
+        writel(addr & 0xff, i2c->regs + TXR);
+        writel(I2C_CMD_START | I2C_CMD_WRITE, i2c->regs + CMDR);
+}
+
+static inline void nuc900_i2c_stop(struct nuc900_i2c *i2c, int ret)
+{
+
+        dev_dbg(i2c->dev, "STOP\n");
+
+        /* stop the transfer */
+        i2c->state = STATE_STOP;
+        writel(I2C_CMD_STOP, i2c->regs + CMDR);
+
+        nuc900_i2c_master_complete(i2c, ret);
+        nuc900_i2c_disable_irq(i2c);
+}
+
+/* helper functions to determine the current state in the set of
+ * messages we are sending
+*/
+
+/* is_lastmsg()
+ *
+ * returns TRUE if the current message is the last in the set
+*/
+
+static inline int is_lastmsg(struct nuc900_i2c *i2c)
+{
+        return i2c->msg_idx >= (i2c->msg_num - 1);
+}
+
+/* is_msglast
+ *
+ * returns TRUE if we this is the last byte in the current message
+*/
+
+static inline int is_msglast(struct nuc900_i2c *i2c)
+{
+        return i2c->msg_ptr == i2c->msg->len-1;
+}
+
+/* is_msgend
+ *
+ * returns TRUE if we reached the end of the current message
+*/
+
+static inline int is_msgend(struct nuc900_i2c *i2c)
+{
+        return i2c->msg_ptr >= i2c->msg->len;
+}
+
+/* i2c_nuc900_irq_nextbyte
+ *
+ * process an interrupt and work out what to do
+ */
+
+static void i2c_nuc900_irq_nextbyte(struct nuc900_i2c *i2c,
+                                                        unsigned long iicstat)
+{
+        unsigned char byte;
+
+        switch (i2c->state) {
+
+        case STATE_IDLE:
+                dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
+                break;
+
+        case STATE_STOP:
+                dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
+                nuc900_i2c_disable_irq(i2c);
+                break;
+
+        case STATE_START:
+                /* last thing we did was send a start condition on the
+                 * bus, or started a new i2c message
+                 */
+
+                if (iicstat & SLAVE_ACK &&
+                    !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
+                        /* ack was not received... */
+
+                        dev_dbg(i2c->dev, "ack was not received\n");
+                        nuc900_i2c_stop(i2c, -ENXIO);
+                        break;
+                }
+
+                if (i2c->msg->flags & I2C_M_RD)
+                        i2c->state = STATE_READ;
+                else
+                        i2c->state = STATE_WRITE;
+
+                /* terminate the transfer if there is nothing to do
+                 * as this is used by the i2c probe to find devices.
+                */
+
+                if (is_lastmsg(i2c) && i2c->msg->len == 0) {
+                        nuc900_i2c_stop(i2c, 0);
+                        break;
+                }
+
+                if (i2c->state == STATE_READ)
+                        goto prepare_read;
+
+                /* fall through to the write state, as we will need to
+                 * send a byte as well
+                */
+
+        case STATE_WRITE:
+                /* we are writing data to the device... check for the
+                 * end of the message, and if so, work out what to do
+                 */
+
+                if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
+                        if (iicstat & SLAVE_ACK) {
+                                dev_dbg(i2c->dev, "WRITE: No Ack\n");
+
+                                nuc900_i2c_stop(i2c, -ECONNREFUSED);
+                                break;
+                        }
+                }
+
+retry_write:
+
+                if (!is_msgend(i2c)) {
+                        byte = i2c->msg->buf[i2c->msg_ptr++];
+                        writeb(byte, i2c->regs + TXR);
+                        writel(I2C_CMD_WRITE, i2c->regs + CMDR);
+
+                } else if (!is_lastmsg(i2c)) {
+                        /* we need to go to the next i2c message */
+
+                        dev_dbg(i2c->dev, "WRITE: Next Message\n");
+
+                        i2c->msg_ptr = 0;
+                        i2c->msg_idx++;
+                        i2c->msg++;
+
+                        /* check to see if we need to do another message */
+                        if (i2c->msg->flags & I2C_M_NOSTART) {
+
+                                if (i2c->msg->flags & I2C_M_RD) {
+                                        /* cannot do this, the controller
+                                         * forces us to send a new START
+                                         * when we change direction
+                                        */
+
+                                        nuc900_i2c_stop(i2c, -EINVAL);
+                                }
+
+                                goto retry_write;
+                        } else {
+                                /* send the new start */
+                                nuc900_i2c_message_start(i2c, i2c->msg);
+                                i2c->state = STATE_START;
+                        }
+
+                } else {
+                        /* send stop */
+
+                        nuc900_i2c_stop(i2c, 0);
+                }
+                break;
+
+        case STATE_READ:
+                /* we have a byte of data in the data register, do
+                 * something with it, and then work out wether we are
+                 * going to do any more read/write
+                 */
+
+                byte = readb(i2c->regs + RXR);
+                i2c->msg->buf[i2c->msg_ptr++] = byte;
+
+prepare_read:
+                if (is_msglast(i2c)) {
+                        /* last byte of buffer */
+
+                        if (is_lastmsg(i2c))
+                                writel(I2C_CMD_READ | I2C_CMD_NACK,
+                                                        i2c->regs + CMDR);
+
+                } else if (is_msgend(i2c)) {
+                        /* ok, we've read the entire buffer, see if there
+                         * is anything else we need to do
+                        */
+
+                        if (is_lastmsg(i2c)) {
+                                /* last message, send stop and complete */
+                                dev_dbg(i2c->dev, "READ: Send Stop\n");
+
+                                nuc900_i2c_stop(i2c, 0);
+                        } else {
+                                /* go to the next transfer */
+                                dev_dbg(i2c->dev, "READ: Next Transfer\n");
+
+                                i2c->msg_ptr = 0;
+                                i2c->msg_idx++;
+                                i2c->msg++;
+
+                                writel(I2C_CMD_READ, i2c->regs + CMDR);
+                        }
+
+                } else {
+                        writel(I2C_CMD_READ, i2c->regs + CMDR);
+                }
+
+                break;
+        }
+}
+
+/* nuc900_i2c_irq
+ *
+ * top level IRQ servicing routine
+*/
+
+static irqreturn_t nuc900_i2c_irq(int irqno, void *dev_id)
+{
+        struct nuc900_i2c *i2c = dev_id;
+        unsigned long status;
+
+        status = readl(i2c->regs + CSR);
+        writel(status | IRQFLAG, i2c->regs + CSR);
+
+        if (status & ARBIT_LOST) {
+                /* deal with arbitration loss */
+                dev_err(i2c->dev, "deal with arbitration loss\n");
+                goto out;
+        }
+
+        if (i2c->state == STATE_IDLE) {
+                dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
+                goto out;
+        }
+
+        /* pretty much this leaves us with the fact that we've
+         * transmitted or received whatever byte we last sent
+        */
+
+        i2c_nuc900_irq_nextbyte(i2c, status);
+
+ out:
+        return IRQ_HANDLED;
+}
+
+
+/* nuc900_i2c_set_master
+ *
+ * get the i2c bus for a master transaction
+*/
+
+static int nuc900_i2c_set_master(struct nuc900_i2c *i2c)
+{
+        int timeout = 400;
+
+        while (timeout-- > 0) {
+                if (((readl(i2c->regs + SWR) & I2CSTART) == I2CSTART) &&
+                                ((readl(i2c->regs + CSR) & I2CBUSY) == 0)) {
+                        return 0;
+                }
+
+                msleep(1);
+        }
+
+        return -ETIMEDOUT;
+}
+
+/* nuc900_i2c_doxfer
+ *
+ * this starts an i2c transfer
+*/
+
+static int nuc900_i2c_doxfer(struct nuc900_i2c *i2c,
+                              struct i2c_msg *msgs, int num)
+{
+        unsigned long iicstat, timeout;
+        int spins = 20;
+        int ret;
+
+        ret = nuc900_i2c_set_master(i2c);
+        if (ret != 0) {
+                dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
+                ret = -EAGAIN;
+                goto out;
+        }
+
+        spin_lock_irq(&i2c->lock);
+
+        i2c->msg     = msgs;
+        i2c->msg_num = num;
+        i2c->msg_ptr = 0;
+        i2c->msg_idx = 0;
+        i2c->state   = STATE_START;
+
+        nuc900_i2c_message_start(i2c, msgs);
+        spin_unlock_irq(&i2c->lock);
+
+        timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
+
+        ret = i2c->msg_idx;
+
+        /* having these next two as dev_err() makes life very
+         * noisy when doing an i2cdetect
+        */
+
+        if (timeout == 0)
+                dev_dbg(i2c->dev, "timeout\n");
+        else if (ret != num)
+                dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
+
+        /* ensure the stop has been through the bus */
+
+        dev_dbg(i2c->dev, "waiting for bus idle\n");
+
+        /* first, try busy waiting briefly */
+        do {
+                iicstat = readl(i2c->regs + CSR);
+        } while ((iicstat & I2CBUSY) && --spins);
+
+        /* if that timed out sleep */
+        if (!spins) {
+                msleep(1);
+                iicstat = readl(i2c->regs + CSR);
+        }
+
+        if (iicstat & I2CBUSY)
+                dev_warn(i2c->dev, "timeout waiting for bus idle\n");
+
+ out:
+        return ret;
+}
+
+/* nuc900_i2c_xfer
+ *
+ * first port of call from the i2c bus code when an message needs
+ * transferring across the i2c bus.
+*/
+
+static int nuc900_i2c_xfer(struct i2c_adapter *adap,
+                        struct i2c_msg *msgs, int num)
+{
+        struct nuc900_i2c *i2c = (struct nuc900_i2c *)adap->algo_data;
+        int retry;
+        int ret;
+
+        nuc900_i2c_enable_irq(i2c);
+
+        for (retry = 0; retry < adap->retries; retry++) {
+
+                ret = nuc900_i2c_doxfer(i2c, msgs, num);
+
+                if (ret != -EAGAIN)
+                        return ret;
+
+                dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
+
+                udelay(100);
+        }
+
+        return -EREMOTEIO;
+}
+
+/* declare our i2c functionality */
+static u32 nuc900_i2c_func(struct i2c_adapter *adap)
+{
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
+}
+
+/* i2c bus registration info */
+
+static const struct i2c_algorithm nuc900_i2c_algorithm = {
+        .master_xfer            = nuc900_i2c_xfer,
+        .functionality          = nuc900_i2c_func,
+};
+
+/* nuc900_i2c_probe
+ *
+ * called by the bus driver when a suitable device is found
+*/
+
+static int __devinit nuc900_i2c_probe(struct platform_device *pdev)
+{
+        struct nuc900_i2c *i2c;
+        struct nuc900_platform_i2c *pdata;
+        struct resource *res;
+        int ret;
+
+        pdata = pdev->dev.platform_data;
+        if (!pdata) {
+                dev_err(&pdev->dev, "no platform data\n");
+                return -EINVAL;
+        }
+
+        i2c = kzalloc(sizeof(struct nuc900_i2c), GFP_KERNEL);
+        if (!i2c) {
+                dev_err(&pdev->dev, "no memory for state\n");
+                return -ENOMEM;
+        }
+
+        strlcpy(i2c->adap.name, "nuc900-i2c0", sizeof(i2c->adap.name));
+        i2c->adap.owner   = THIS_MODULE;
+        i2c->adap.algo    = &nuc900_i2c_algorithm;
+        i2c->adap.retries = 2;
+        i2c->adap.class   = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+
+        spin_lock_init(&i2c->lock);
+        init_waitqueue_head(&i2c->wait);
+
+        /* find the clock and enable it */
+
+        i2c->dev = &pdev->dev;
+        i2c->clk = clk_get(&pdev->dev, NULL);
+        if (IS_ERR(i2c->clk)) {
+                dev_err(&pdev->dev, "cannot get clock\n");
+                ret = -ENOENT;
+                goto err_noclk;
+        }
+
+        dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
+
+        clk_enable(i2c->clk);
+
+        /* map the registers */
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (res == NULL) {
+                dev_err(&pdev->dev, "cannot find IO resource\n");
+                ret = -ENOENT;
+                goto err_clk;
+        }
+
+        i2c->ioarea = request_mem_region(res->start, resource_size(res),
+                                         pdev->name);
+
+        if (i2c->ioarea == NULL) {
+                dev_err(&pdev->dev, "cannot request IO\n");
+                ret = -ENXIO;
+                goto err_clk;
+        }
+
+        i2c->regs = ioremap(res->start, resource_size(res));
+
+        if (i2c->regs == NULL) {
+                dev_err(&pdev->dev, "cannot map IO\n");
+                ret = -ENXIO;
+                goto err_ioarea;
+        }
+
+        dev_dbg(&pdev->dev, "registers %p (%p, %p)\n",
+                i2c->regs, i2c->ioarea, res);
+
+        /* setup info block for the i2c core */
+
+        i2c->adap.algo_data = i2c;
+        i2c->adap.dev.parent = &pdev->dev;
+
+        mfp_set_groupg(&pdev->dev);
+
+        clk_get_rate(i2c->clk);
+
+        ret = (i2c->clk.apbfreq)/(pdata->bus_freq * 5) - 1;
+        writel(ret & 0xffff, i2c->regs + DIVIDER);
+
+        /* find the IRQ for this unit (note, this relies on the init call to
+         * ensure no current IRQs pending
+         */
+
+        i2c->irq = ret = platform_get_irq(pdev, 0);
+        if (ret <= 0) {
+                dev_err(&pdev->dev, "cannot find IRQ\n");
+                goto err_iomap;
+        }
+
+        ret = request_irq(i2c->irq, nuc900_i2c_irq, IRQF_DISABLED | IRQF_SHARED,
+                          dev_name(&pdev->dev), i2c);
+
+        if (ret != 0) {
+                dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
+                goto err_iomap;
+        }
+
+        /* Note, previous versions of the driver used i2c_add_adapter()
+         * to add the bus at any number. We now pass the bus number via
+         * the platform data, so if unset it will now default to always
+         * being bus 0.
+         */
+
+        i2c->adap.nr = pdata->bus_num;
+
+        ret = i2c_add_numbered_adapter(&i2c->adap);
+        if (ret < 0) {
+                dev_err(&pdev->dev, "failed to add bus to i2c core\n");
+                goto err_irq;
+        }
+
+        platform_set_drvdata(pdev, i2c);
+
+        dev_info(&pdev->dev, "%s: NUC900 I2C adapter\n",
+                                                dev_name(&i2c->adap.dev));
+        return 0;
+
+ err_irq:
+        free_irq(i2c->irq, i2c);
+
+ err_iomap:
+        iounmap(i2c->regs);
+
+ err_ioarea:
+        release_resource(i2c->ioarea);
+        kfree(i2c->ioarea);
+
+ err_clk:
+        clk_disable(i2c->clk);
+        clk_put(i2c->clk);
+
+ err_noclk:
+        kfree(i2c);
+        return ret;
+}
+
+/* nuc900_i2c_remove
+ *
+ * called when device is removed from the bus
+*/
+
+static int __devexit nuc900_i2c_remove(struct platform_device *pdev)
+{
+        struct nuc900_i2c *i2c = platform_get_drvdata(pdev);
+
+        i2c_del_adapter(&i2c->adap);
+        free_irq(i2c->irq, i2c);
+
+        clk_disable(i2c->clk);
+        clk_put(i2c->clk);
+
+        iounmap(i2c->regs);
+
+        release_resource(i2c->ioarea);
+        kfree(i2c->ioarea);
+        kfree(i2c);
+
+        return 0;
+}
+
+static struct platform_driver nuc900_i2c_driver = {
+        .probe          = nuc900_i2c_probe,
+        .remove         = __devexit_p(nuc900_i2c_remove),
+        .driver         = {
+                .owner  = THIS_MODULE,
+                .name   = "nuc900-i2c0",
+        },
+};
+
+static int __init i2c_adap_nuc900_init(void)
+{
+        return platform_driver_register(&nuc900_i2c_driver);
+}
+
+static void __exit i2c_adap_nuc900_exit(void)
+{
+        platform_driver_unregister(&nuc900_i2c_driver);
+}
+subsys_initcall(i2c_adap_nuc900_init);
+module_exit(i2c_adap_nuc900_exit);
+
+MODULE_DESCRIPTION("NUC900 I2C Bus driver");
+MODULE_AUTHOR("Wan ZongShun, <mcuos.com-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:nuc900-i2c0");
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 020ff23d762f..c94e51b2651e 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -1001,7 +1001,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
         struct pxa_i2c *i2c;
         struct resource *res;
         struct i2c_pxa_platform_data *plat = dev->dev.platform_data;
-        struct platform_device_id *id = platform_get_device_id(dev);
+        const struct platform_device_id *id = platform_get_device_id(dev);
         int ret;
         int irq;
 
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 97b84b80d0ff..2707f5e17158 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -119,8 +119,10 @@ struct sh_mobile_i2c_data {
         struct i2c_adapter adap;
 
         struct clk *clk;
+        u_int8_t icic;
         u_int8_t iccl;
         u_int8_t icch;
+        u_int8_t flags;
 
         spinlock_t lock;
         wait_queue_head_t wait;
@@ -129,15 +131,17 @@ struct sh_mobile_i2c_data {
         int sr;
 };
 
+#define IIC_FLAG_HAS_ICIC67     (1 << 0)
+
 #define NORMAL_SPEED            100000 /* FAST_SPEED 400000 */
 
 /* Register offsets */
-#define ICDR(pd)                (pd->reg + 0x00)
-#define ICCR(pd)                (pd->reg + 0x04)
-#define ICSR(pd)                (pd->reg + 0x08)
-#define ICIC(pd)                (pd->reg + 0x0c)
-#define ICCL(pd)                (pd->reg + 0x10)
-#define ICCH(pd)                (pd->reg + 0x14)
+#define ICDR                    0x00
+#define ICCR                    0x04
+#define ICSR                    0x08
+#define ICIC                    0x0c
+#define ICCL                    0x10
+#define ICCH                    0x14
 
 /* Register bits */
 #define ICCR_ICE                0x80
@@ -155,11 +159,32 @@ struct sh_mobile_i2c_data {
 #define ICSR_WAIT               0x02
 #define ICSR_DTE                0x01
 
+#define ICIC_ICCLB8             0x80
+#define ICIC_ICCHB8             0x40
 #define ICIC_ALE                0x08
 #define ICIC_TACKE              0x04
 #define ICIC_WAITE              0x02
 #define ICIC_DTEE               0x01
 
+static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
+{
+        if (offs == ICIC)
+                data |= pd->icic;
+
+        iowrite8(data, pd->reg + offs);
+}
+
+static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
+{
+        return ioread8(pd->reg + offs);
+}
+
+static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
+                        unsigned char set, unsigned char clr)
+{
+        iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr);
+}
+
 static void activate_ch(struct sh_mobile_i2c_data *pd)
 {
         unsigned long i2c_clk;
@@ -187,6 +212,14 @@ static void activate_ch(struct sh_mobile_i2c_data *pd)
         else
                 pd->iccl = (u_int8_t)(num/denom);
 
+        /* one more bit of ICCL in ICIC */
+        if (pd->flags & IIC_FLAG_HAS_ICIC67) {
+                if ((num/denom) > 0xff)
+                        pd->icic |= ICIC_ICCLB8;
+                else
+                        pd->icic &= ~ICIC_ICCLB8;
+        }
+
         /* Calculate the value for icch. From the data sheet:
            icch = (p clock / transfer rate) * (H / (L + H)) */
         num = i2c_clk * 4;
@@ -196,25 +229,33 @@ static void activate_ch(struct sh_mobile_i2c_data *pd)
         else
                 pd->icch = (u_int8_t)(num/denom);
 
+        /* one more bit of ICCH in ICIC */
+        if (pd->flags & IIC_FLAG_HAS_ICIC67) {
+                if ((num/denom) > 0xff)
+                        pd->icic |= ICIC_ICCHB8;
+                else
+                        pd->icic &= ~ICIC_ICCHB8;
+        }
+
         /* Enable channel and configure rx ack */
-        iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
+        iic_set_clr(pd, ICCR, ICCR_ICE, 0);
 
         /* Mask all interrupts */
-        iowrite8(0, ICIC(pd));
+        iic_wr(pd, ICIC, 0);
 
         /* Set the clock */
-        iowrite8(pd->iccl, ICCL(pd));
-        iowrite8(pd->icch, ICCH(pd));
+        iic_wr(pd, ICCL, pd->iccl);
+        iic_wr(pd, ICCH, pd->icch);
 }
 
 static void deactivate_ch(struct sh_mobile_i2c_data *pd)
 {
         /* Clear/disable interrupts */
-        iowrite8(0, ICSR(pd));
-        iowrite8(0, ICIC(pd));
+        iic_wr(pd, ICSR, 0);
+        iic_wr(pd, ICIC, 0);
 
         /* Disable channel */
-        iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
+        iic_set_clr(pd, ICCR, 0, ICCR_ICE);
 
         /* Disable clock and mark device as idle */
         clk_disable(pd->clk);
@@ -233,35 +274,35 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
 
         switch (op) {
         case OP_START: /* issue start and trigger DTE interrupt */
-                iowrite8(0x94, ICCR(pd));
+                iic_wr(pd, ICCR, 0x94);
                 break;
         case OP_TX_FIRST: /* disable DTE interrupt and write data */
-                iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE, ICIC(pd));
-                iowrite8(data, ICDR(pd));
+                iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
+                iic_wr(pd, ICDR, data);
                 break;
         case OP_TX: /* write data */
-                iowrite8(data, ICDR(pd));
+                iic_wr(pd, ICDR, data);
                 break;
         case OP_TX_STOP: /* write data and issue a stop afterwards */
-                iowrite8(data, ICDR(pd));
-                iowrite8(0x90, ICCR(pd));
+                iic_wr(pd, ICDR, data);
+                iic_wr(pd, ICCR, 0x90);
                 break;
         case OP_TX_TO_RX: /* select read mode */
-                iowrite8(0x81, ICCR(pd));
+                iic_wr(pd, ICCR, 0x81);
                 break;
         case OP_RX: /* just read data */
-                ret = ioread8(ICDR(pd));
+                ret = iic_rd(pd, ICDR);
                 break;
         case OP_RX_STOP: /* enable DTE interrupt, issue stop */
-                iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
-                         ICIC(pd));
-                iowrite8(0xc0, ICCR(pd));
+                iic_wr(pd, ICIC,
+                       ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
+                iic_wr(pd, ICCR, 0xc0);
                 break;
         case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
-                iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
-                         ICIC(pd));
-                ret = ioread8(ICDR(pd));
-                iowrite8(0xc0, ICCR(pd));
+                iic_wr(pd, ICIC,
+                       ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
+                ret = iic_rd(pd, ICDR);
+                iic_wr(pd, ICCR, 0xc0);
                 break;
         }
 
@@ -367,7 +408,7 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
         unsigned char sr;
         int wakeup;
 
-        sr = ioread8(ICSR(pd));
+        sr = iic_rd(pd, ICSR);
         pd->sr |= sr; /* remember state */
 
         dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
@@ -376,7 +417,7 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
 
         if (sr & (ICSR_AL | ICSR_TACK)) {
                 /* don't interrupt transaction - continue to issue stop */
-                iowrite8(sr & ~(ICSR_AL | ICSR_TACK), ICSR(pd));
+                iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
                 wakeup = 0;
         } else if (pd->msg->flags & I2C_M_RD)
                 wakeup = sh_mobile_i2c_isr_rx(pd);
@@ -384,7 +425,7 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
                 wakeup = sh_mobile_i2c_isr_tx(pd);
 
         if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
-                iowrite8(sr & ~ICSR_WAIT, ICSR(pd));
+                iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
 
         if (wakeup) {
                 pd->sr |= SW_DONE;
@@ -402,21 +443,21 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
         }
 
         /* Initialize channel registers */
-        iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
+        iic_set_clr(pd, ICCR, 0, ICCR_ICE);
 
         /* Enable channel and configure rx ack */
-        iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
+        iic_set_clr(pd, ICCR, ICCR_ICE, 0);
 
         /* Set the clock */
-        iowrite8(pd->iccl, ICCL(pd));
-        iowrite8(pd->icch, ICCH(pd));
+        iic_wr(pd, ICCL, pd->iccl);
+        iic_wr(pd, ICCH, pd->icch);
 
         pd->msg = usr_msg;
         pd->pos = -1;
         pd->sr = 0;
 
         /* Enable all interrupts to begin with */
-        iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, ICIC(pd));
+        iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
         return 0;
 }
 
@@ -451,7 +492,7 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
 
                 retry_count = 1000;
 again:
-                val = ioread8(ICSR(pd));
+                val = iic_rd(pd, ICSR);
 
                 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
 
@@ -579,6 +620,12 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
                 goto err_irq;
         }
 
+        /* The IIC blocks on SH-Mobile ARM processors
+         * come with two new bits in ICIC.
+         */
+        if (size > 0x17)
+                pd->flags |= IIC_FLAG_HAS_ICIC67;
+
         /* Enable Runtime PM for this device.
          *
          * Also tell the Runtime PM core to ignore children
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 0815e10da7c6..6649176de940 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -20,7 +20,9 @@
 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
    All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
    SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
-   Jean Delvare <khali@linux-fr.org> */
+   Jean Delvare <khali@linux-fr.org>
+   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
+   Michael Lawnick <michael.lawnick.ext@nsn.com> */
 
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -30,6 +32,8 @@
 #include <linux/init.h>
 #include <linux/idr.h>
 #include <linux/mutex.h>
+#include <linux/of_i2c.h>
+#include <linux/of_device.h>
 #include <linux/completion.h>
 #include <linux/hardirq.h>
 #include <linux/irqflags.h>
@@ -70,6 +74,10 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
         if (!client)
                 return 0;
 
+        /* Attempt an OF style match */
+        if (of_driver_match_device(dev, drv))
+                return 1;
+
         driver = to_i2c_driver(drv);
         /* match on an id table if there is one */
         if (driver->id_table)
@@ -417,11 +425,87 @@ static int __i2c_check_addr_busy(struct device *dev, void *addrp)
         return 0;
 }
 
+/* walk up mux tree */
+static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
+{
+        int result;
+
+        result = device_for_each_child(&adapter->dev, &addr,
+                                        __i2c_check_addr_busy);
+
+        if (!result && i2c_parent_is_i2c_adapter(adapter))
+                result = i2c_check_mux_parents(
+                                    to_i2c_adapter(adapter->dev.parent), addr);
+
+        return result;
+}
+
+/* recurse down mux tree */
+static int i2c_check_mux_children(struct device *dev, void *addrp)
+{
+        int result;
+
+        if (dev->type == &i2c_adapter_type)
+                result = device_for_each_child(dev, addrp,
+                                                i2c_check_mux_children);
+        else
+                result = __i2c_check_addr_busy(dev, addrp);
+
+        return result;
+}
+
 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 {
-        return device_for_each_child(&adapter->dev, &addr,
-                                     __i2c_check_addr_busy);
+        int result = 0;
+
+        if (i2c_parent_is_i2c_adapter(adapter))
+                result = i2c_check_mux_parents(
+                                    to_i2c_adapter(adapter->dev.parent), addr);
+
+        if (!result)
+                result = device_for_each_child(&adapter->dev, &addr,
+                                                i2c_check_mux_children);
+
+        return result;
+}
+
+/**
+ * i2c_lock_adapter - Get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+void i2c_lock_adapter(struct i2c_adapter *adapter)
+{
+        if (i2c_parent_is_i2c_adapter(adapter))
+                i2c_lock_adapter(to_i2c_adapter(adapter->dev.parent));
+        else
+                rt_mutex_lock(&adapter->bus_lock);
+}
+EXPORT_SYMBOL_GPL(i2c_lock_adapter);
+
+/**
+ * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+static int i2c_trylock_adapter(struct i2c_adapter *adapter)
+{
+        if (i2c_parent_is_i2c_adapter(adapter))
+                return i2c_trylock_adapter(to_i2c_adapter(adapter->dev.parent));
+        else
+                return rt_mutex_trylock(&adapter->bus_lock);
+}
+
+/**
+ * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+void i2c_unlock_adapter(struct i2c_adapter *adapter)
+{
+        if (i2c_parent_is_i2c_adapter(adapter))
+                i2c_unlock_adapter(to_i2c_adapter(adapter->dev.parent));
+        else
+                rt_mutex_unlock(&adapter->bus_lock);
 }
+EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
 
 /**
  * i2c_new_device - instantiate an i2c device
@@ -627,9 +711,9 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
                 return -EINVAL;
 
         /* Keep track of the added device */
-        i2c_lock_adapter(adap);
+        mutex_lock(&adap->userspace_clients_lock);
         list_add_tail(&client->detected, &adap->userspace_clients);
-        i2c_unlock_adapter(adap);
+        mutex_unlock(&adap->userspace_clients_lock);
         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
                  info.type, info.addr);
 
@@ -668,7 +752,7 @@ i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
 
         /* Make sure the device was added through sysfs */
         res = -ENOENT;
-        i2c_lock_adapter(adap);
+        mutex_lock(&adap->userspace_clients_lock);
         list_for_each_entry_safe(client, next, &adap->userspace_clients,
                                  detected) {
                 if (client->addr == addr) {
@@ -681,7 +765,7 @@ i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
                         break;
                 }
         }
-        i2c_unlock_adapter(adap);
+        mutex_unlock(&adap->userspace_clients_lock);
 
         if (res < 0)
                 dev_err(dev, "%s: Can't find device in list\n",
@@ -708,10 +792,11 @@ static const struct attribute_group *i2c_adapter_attr_groups[] = {
         NULL
 };
 
-static struct device_type i2c_adapter_type = {
+struct device_type i2c_adapter_type = {
         .groups         = i2c_adapter_attr_groups,
         .release        = i2c_adapter_dev_release,
 };
+EXPORT_SYMBOL_GPL(i2c_adapter_type);
 
 #ifdef CONFIG_I2C_COMPAT
 static struct class_compat *i2c_adapter_compat_class;
@@ -754,7 +839,7 @@ static int __process_new_adapter(struct device_driver *d, void *data)
 
 static int i2c_register_adapter(struct i2c_adapter *adap)
 {
-        int res = 0, dummy;
+        int res = 0;
 
         /* Can't register until after driver model init */
         if (unlikely(WARN_ON(!i2c_bus_type.p))) {
@@ -763,6 +848,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
         }
 
         rt_mutex_init(&adap->bus_lock);
+        mutex_init(&adap->userspace_clients_lock);
         INIT_LIST_HEAD(&adap->userspace_clients);
 
         /* Set default timeout to 1 second if not already set */
@@ -790,10 +876,12 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
         if (adap->nr < __i2c_first_dynamic_bus_num)
                 i2c_scan_static_board_info(adap);
 
+        /* Register devices from the device tree */
+        of_i2c_register_devices(adap);
+
         /* Notify drivers */
         mutex_lock(&core_lock);
-        dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap,
-                                 __process_new_adapter);
+        bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
         mutex_unlock(&core_lock);
 
         return 0;
@@ -966,7 +1054,7 @@ int i2c_del_adapter(struct i2c_adapter *adap)
                 return res;
 
         /* Remove devices instantiated from sysfs */
-        i2c_lock_adapter(adap);
+        mutex_lock(&adap->userspace_clients_lock);
         list_for_each_entry_safe(client, next, &adap->userspace_clients,
                                  detected) {
                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
@@ -974,7 +1062,7 @@ int i2c_del_adapter(struct i2c_adapter *adap)
                 list_del(&client->detected);
                 i2c_unregister_device(client);
         }
-        i2c_unlock_adapter(adap);
+        mutex_unlock(&adap->userspace_clients_lock);
 
         /* Detach any active clients. This can't fail, thus we do not
            checking the returned value. */
@@ -1229,12 +1317,12 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 #endif
 
                 if (in_atomic() || irqs_disabled()) {
-                        ret = rt_mutex_trylock(&adap->bus_lock);
+                        ret = i2c_trylock_adapter(adap);
                         if (!ret)
                                 /* I2C activity is ongoing. */
                                 return -EAGAIN;
                 } else {
-                        rt_mutex_lock(&adap->bus_lock);
+                        i2c_lock_adapter(adap);
                 }
 
                 /* Retry automatically on arbitration loss */
@@ -1246,7 +1334,7 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
                         if (time_after(jiffies, orig_jiffies + adap->timeout))
                                 break;
                 }
-                rt_mutex_unlock(&adap->bus_lock);
+                i2c_unlock_adapter(adap);
 
                 return ret;
         } else {
@@ -1341,13 +1429,17 @@ static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
                                      I2C_SMBUS_BYTE_DATA, &dummy);
         else
 #endif
-        if ((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50
-         || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
-                err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
-                                     I2C_SMBUS_BYTE, &dummy);
-        else
+        if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
+         && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
                                      I2C_SMBUS_QUICK, NULL);
+        else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
+                err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
+                                     I2C_SMBUS_BYTE, &dummy);
+        else {
+                dev_warn(&adap->dev, "No suitable probing method supported\n");
+                err = -EOPNOTSUPP;
+        }
 
         return err >= 0;
 }
@@ -1428,16 +1520,6 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
         if (!(adapter->class & driver->class))
                 goto exit_free;
 
-        /* Stop here if the bus doesn't support probing */
-        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE)) {
-                if (address_list[0] == I2C_CLIENT_END)
-                        goto exit_free;
-
-                dev_warn(&adapter->dev, "Probing not supported\n");
-                err = -EOPNOTSUPP;
-                goto exit_free;
-        }
-
         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
                 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
                         "addr 0x%02x\n", adap_id, address_list[i]);
@@ -1452,18 +1534,23 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
         return err;
 }
 
+int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
+{
+        return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
+                              I2C_SMBUS_QUICK, NULL) >= 0;
+}
+EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
+
 struct i2c_client *
 i2c_new_probed_device(struct i2c_adapter *adap,
                       struct i2c_board_info *info,
-                      unsigned short const *addr_list)
+                      unsigned short const *addr_list,
+                      int (*probe)(struct i2c_adapter *, unsigned short addr))
 {
         int i;
 
-        /* Stop here if the bus doesn't support probing */
-        if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) {
-                dev_err(&adap->dev, "Probing not supported\n");
-                return NULL;
-        }
+        if (!probe)
+                probe = i2c_default_probe;
 
         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
                 /* Check address validity */
@@ -1481,7 +1568,7 @@ i2c_new_probed_device(struct i2c_adapter *adap,
                 }
 
                 /* Test address responsiveness */
-                if (i2c_default_probe(adap, addr_list[i]))
+                if (probe(adap, addr_list[i]))
                         break;
         }
 
@@ -1993,7 +2080,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
         flags &= I2C_M_TEN | I2C_CLIENT_PEC;
 
         if (adapter->algo->smbus_xfer) {
-                rt_mutex_lock(&adapter->bus_lock);
+                i2c_lock_adapter(adapter);
 
                 /* Retry automatically on arbitration loss */
                 orig_jiffies = jiffies;
@@ -2007,7 +2094,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
                                        orig_jiffies + adapter->timeout))
                                 break;
                 }
-                rt_mutex_unlock(&adapter->bus_lock);
+                i2c_unlock_adapter(adapter);
         } else
                 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
                                               command, protocol, data);
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index e0694e4d86c7..5f3a52d517c3 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -167,13 +167,9 @@ static ssize_t i2cdev_write(struct file *file, const char __user *buf,
         if (count > 8192)
                 count = 8192;
 
-        tmp = kmalloc(count, GFP_KERNEL);
-        if (tmp == NULL)
-                return -ENOMEM;
-        if (copy_from_user(tmp, buf, count)) {
-                kfree(tmp);
-                return -EFAULT;
-        }
+        tmp = memdup_user(buf, count);
+        if (IS_ERR(tmp))
+                return PTR_ERR(tmp);
 
         pr_debug("i2c-dev: i2c-%d writing %zu bytes.\n",
                 iminor(file->f_path.dentry->d_inode), count);
@@ -193,12 +189,50 @@ static int i2cdev_check(struct device *dev, void *addrp)
         return dev->driver ? -EBUSY : 0;
 }
 
+/* walk up mux tree */
+static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
+{
+        int result;
+
+        result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
+
+        if (!result && i2c_parent_is_i2c_adapter(adapter))
+                result = i2cdev_check_mux_parents(
+                                    to_i2c_adapter(adapter->dev.parent), addr);
+
+        return result;
+}
+
+/* recurse down mux tree */
+static int i2cdev_check_mux_children(struct device *dev, void *addrp)
+{
+        int result;
+
+        if (dev->type == &i2c_adapter_type)
+                result = device_for_each_child(dev, addrp,
+                                                i2cdev_check_mux_children);
+        else
+                result = i2cdev_check(dev, addrp);
+
+        return result;
+}
+
 /* This address checking function differs from the one in i2c-core
    in that it considers an address with a registered device, but no
    driver bound to it, as NOT busy. */
 static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
 {
-        return device_for_each_child(&adapter->dev, &addr, i2cdev_check);
+        int result = 0;
+
+        if (i2c_parent_is_i2c_adapter(adapter))
+                result = i2cdev_check_mux_parents(
+                                    to_i2c_adapter(adapter->dev.parent), addr);
+
+        if (!result)
+                result = device_for_each_child(&adapter->dev, &addr,
+                                                i2cdev_check_mux_children);
+
+        return result;
 }
 
 static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
@@ -219,9 +253,7 @@ static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
         if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
                 return -EINVAL;
 
-        rdwr_pa = (struct i2c_msg *)
-                kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
-                GFP_KERNEL);
+        rdwr_pa = kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg), GFP_KERNEL);
         if (!rdwr_pa)
                 return -ENOMEM;
 
@@ -247,15 +279,9 @@ static noinline int i2cdev_ioctl_rdrw(struct i2c_client *client,
                         break;
                 }
                 data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
-                rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
-                if (rdwr_pa[i].buf == NULL) {
-                        res = -ENOMEM;
-                        break;
-                }
-                if (copy_from_user(rdwr_pa[i].buf, data_ptrs[i],
-                                   rdwr_pa[i].len)) {
-                                ++i; /* Needs to be kfreed too */
-                                res = -EFAULT;
+                rdwr_pa[i].buf = memdup_user(data_ptrs[i], rdwr_pa[i].len);
+                if (IS_ERR(rdwr_pa[i].buf)) {
+                        res = PTR_ERR(rdwr_pa[i].buf);
                         break;
                 }
         }
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
new file mode 100644
index 000000000000..d32a4843fc3a
--- /dev/null
+++ b/drivers/i2c/i2c-mux.c
@@ -0,0 +1,165 @@
+/*
+ * Multiplexed I2C bus driver.
+ *
+ * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
+ * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
+ * Copyright (c) 2009-2010 NSN GmbH & Co KG <michael.lawnick.ext@nsn.com>
+ *
+ * Simplifies access to complex multiplexed I2C bus topologies, by presenting
+ * each multiplexed bus segment as an additional I2C adapter.
+ * Supports multi-level mux'ing (mux behind a mux).
+ *
+ * Based on:
+ *      i2c-virt.c from Kumar Gala <galak@kernel.crashing.org>
+ *      i2c-virtual.c from Ken Harrenstien, Copyright (c) 2004 Google, Inc.
+ *      i2c-virtual.c from Brian Kuschak <bkuschak@yahoo.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+
+/* multiplexer per channel data */
+struct i2c_mux_priv {
+        struct i2c_adapter adap;
+        struct i2c_algorithm algo;
+
+        struct i2c_adapter *parent;
+        void *mux_dev;  /* the mux chip/device */
+        u32  chan_id;   /* the channel id */
+
+        int (*select)(struct i2c_adapter *, void *mux_dev, u32 chan_id);
+        int (*deselect)(struct i2c_adapter *, void *mux_dev, u32 chan_id);
+};
+
+static int i2c_mux_master_xfer(struct i2c_adapter *adap,
+                               struct i2c_msg msgs[], int num)
+{
+        struct i2c_mux_priv *priv = adap->algo_data;
+        struct i2c_adapter *parent = priv->parent;
+        int ret;
+
+        /* Switch to the right mux port and perform the transfer. */
+
+        ret = priv->select(parent, priv->mux_dev, priv->chan_id);
+        if (ret >= 0)
+                ret = parent->algo->master_xfer(parent, msgs, num);
+        if (priv->deselect)
+                priv->deselect(parent, priv->mux_dev, priv->chan_id);
+
+        return ret;
+}
+
+static int i2c_mux_smbus_xfer(struct i2c_adapter *adap,
+                              u16 addr, unsigned short flags,
+                              char read_write, u8 command,
+                              int size, union i2c_smbus_data *data)
+{
+        struct i2c_mux_priv *priv = adap->algo_data;
+        struct i2c_adapter *parent = priv->parent;
+        int ret;
+
+        /* Select the right mux port and perform the transfer. */
+
+        ret = priv->select(parent, priv->mux_dev, priv->chan_id);
+        if (ret >= 0)
+                ret = parent->algo->smbus_xfer(parent, addr, flags,
+                                        read_write, command, size, data);
+        if (priv->deselect)
+                priv->deselect(parent, priv->mux_dev, priv->chan_id);
+
+        return ret;
+}
+
+/* Return the parent's functionality */
+static u32 i2c_mux_functionality(struct i2c_adapter *adap)
+{
+        struct i2c_mux_priv *priv = adap->algo_data;
+        struct i2c_adapter *parent = priv->parent;
+
+        return parent->algo->functionality(parent);
+}
+
+struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
+                                void *mux_dev, u32 force_nr, u32 chan_id,
+                                int (*select) (struct i2c_adapter *,
+                                               void *, u32),
+                                int (*deselect) (struct i2c_adapter *,
+                                                 void *, u32))
+{
+        struct i2c_mux_priv *priv;
+        int ret;
+
+        priv = kzalloc(sizeof(struct i2c_mux_priv), GFP_KERNEL);
+        if (!priv)
+                return NULL;
+
+        /* Set up private adapter data */
+        priv->parent = parent;
+        priv->mux_dev = mux_dev;
+        priv->chan_id = chan_id;
+        priv->select = select;
+        priv->deselect = deselect;
+
+        /* Need to do algo dynamically because we don't know ahead
+         * of time what sort of physical adapter we'll be dealing with.
+         */
+        if (parent->algo->master_xfer)
+                priv->algo.master_xfer = i2c_mux_master_xfer;
+        if (parent->algo->smbus_xfer)
+                priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
+        priv->algo.functionality = i2c_mux_functionality;
+
+        /* Now fill out new adapter structure */
+        snprintf(priv->adap.name, sizeof(priv->adap.name),
+                 "i2c-%d-mux (chan_id %d)", i2c_adapter_id(parent), chan_id);
+        priv->adap.owner = THIS_MODULE;
+        priv->adap.id = parent->id;
+        priv->adap.algo = &priv->algo;
+        priv->adap.algo_data = priv;
+        priv->adap.dev.parent = &parent->dev;
+
+        if (force_nr) {
+                priv->adap.nr = force_nr;
+                ret = i2c_add_numbered_adapter(&priv->adap);
+        } else {
+                ret = i2c_add_adapter(&priv->adap);
+        }
+        if (ret < 0) {
+                dev_err(&parent->dev,
+                        "failed to add mux-adapter (error=%d)\n",
+                        ret);
+                kfree(priv);
+                return NULL;
+        }
+
+        dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
+                 i2c_adapter_id(&priv->adap));
+
+        return &priv->adap;
+}
+EXPORT_SYMBOL_GPL(i2c_add_mux_adapter);
+
+int i2c_del_mux_adapter(struct i2c_adapter *adap)
+{
+        struct i2c_mux_priv *priv = adap->algo_data;
+        int ret;
+
+        ret = i2c_del_adapter(adap);
+        if (ret < 0)
+                return ret;
+        kfree(priv);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_del_mux_adapter);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("I2C driver for multiplexed I2C busses");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
new file mode 100644
index 000000000000..4c9a99c4fcb0
--- /dev/null
+++ b/drivers/i2c/muxes/Kconfig
@@ -0,0 +1,18 @@
+#
+# Multiplexer I2C chip drivers configuration
+#
+
+menu "Multiplexer I2C Chip support"
+        depends on I2C_MUX
+
+config I2C_MUX_PCA954x
+        tristate "Philips PCA954x I2C Mux/switches"
+        depends on EXPERIMENTAL
+        help
+          If you say yes here you get support for the Philips PCA954x
+          I2C mux/switch devices.
+
+          This driver can also be built as a module.  If so, the module
+          will be called pca954x.
+
+endmenu
diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
new file mode 100644
index 000000000000..bd83b5274815
--- /dev/null
+++ b/drivers/i2c/muxes/Makefile
@@ -0,0 +1,8 @@
+#
+# Makefile for multiplexer I2C chip drivers.
+
+obj-$(CONFIG_I2C_MUX_PCA954x)   += pca954x.o
+
+ifeq ($(CONFIG_I2C_DEBUG_BUS),y)
+EXTRA_CFLAGS += -DDEBUG
+endif
diff --git a/drivers/i2c/muxes/pca954x.c b/drivers/i2c/muxes/pca954x.c
new file mode 100644
index 000000000000..6f9accf3189d
--- /dev/null
+++ b/drivers/i2c/muxes/pca954x.c
@@ -0,0 +1,301 @@
+/*
+ * I2C multiplexer
+ *
+ * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
+ * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
+ *
+ * This module supports the PCA954x series of I2C multiplexer/switch chips
+ * made by Philips Semiconductors.
+ * This includes the:
+ *       PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547
+ *       and PCA9548.
+ *
+ * These chips are all controlled via the I2C bus itself, and all have a
+ * single 8-bit register. The upstream "parent" bus fans out to two,
+ * four, or eight downstream busses or channels; which of these
+ * are selected is determined by the chip type and register contents. A
+ * mux can select only one sub-bus at a time; a switch can select any
+ * combination simultaneously.
+ *
+ * Based on:
+ *      pca954x.c from Kumar Gala <galak@kernel.crashing.org>
+ * Copyright (C) 2006
+ *
+ * Based on:
+ *      pca954x.c from Ken Harrenstien
+ * Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
+ *
+ * Based on:
+ *      i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
+ * and
+ *      pca9540.c from Jean Delvare <khali@linux-fr.org>.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+
+#include <linux/i2c/pca954x.h>
+
+#define PCA954X_MAX_NCHANS 8
+
+enum pca_type {
+        pca_9540,
+        pca_9542,
+        pca_9543,
+        pca_9544,
+        pca_9545,
+        pca_9546,
+        pca_9547,
+        pca_9548,
+};
+
+struct pca954x {
+        enum pca_type type;
+        struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS];
+
+        u8 last_chan;           /* last register value */
+};
+
+struct chip_desc {
+        u8 nchans;
+        u8 enable;      /* used for muxes only */
+        enum muxtype {
+                pca954x_ismux = 0,
+                pca954x_isswi
+        } muxtype;
+};
+
+/* Provide specs for the PCA954x types we know about */
+static const struct chip_desc chips[] = {
+        [pca_9540] = {
+                .nchans = 2,
+                .enable = 0x4,
+                .muxtype = pca954x_ismux,
+        },
+        [pca_9543] = {
+                .nchans = 2,
+                .muxtype = pca954x_isswi,
+        },
+        [pca_9544] = {
+                .nchans = 4,
+                .enable = 0x4,
+                .muxtype = pca954x_ismux,
+        },
+        [pca_9545] = {
+                .nchans = 4,
+                .muxtype = pca954x_isswi,
+        },
+        [pca_9547] = {
+                .nchans = 8,
+                .enable = 0x8,
+                .muxtype = pca954x_ismux,
+        },
+        [pca_9548] = {
+                .nchans = 8,
+                .muxtype = pca954x_isswi,
+        },
+};
+
+static const struct i2c_device_id pca954x_id[] = {
+        { "pca9540", pca_9540 },
+        { "pca9542", pca_9540 },
+        { "pca9543", pca_9543 },
+        { "pca9544", pca_9544 },
+        { "pca9545", pca_9545 },
+        { "pca9546", pca_9545 },
+        { "pca9547", pca_9547 },
+        { "pca9548", pca_9548 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, pca954x_id);
+
+/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
+   for this as they will try to lock adapter a second time */
+static int pca954x_reg_write(struct i2c_adapter *adap,
+                             struct i2c_client *client, u8 val)
+{
+        int ret = -ENODEV;
+
+        if (adap->algo->master_xfer) {
+                struct i2c_msg msg;
+                char buf[1];
+
+                msg.addr = client->addr;
+                msg.flags = 0;
+                msg.len = 1;
+                buf[0] = val;
+                msg.buf = buf;
+                ret = adap->algo->master_xfer(adap, &msg, 1);
+        } else {
+                union i2c_smbus_data data;
+                ret = adap->algo->smbus_xfer(adap, client->addr,
+                                             client->flags,
+                                             I2C_SMBUS_WRITE,
+                                             val, I2C_SMBUS_BYTE, &data);
+        }
+
+        return ret;
+}
+
+static int pca954x_select_chan(struct i2c_adapter *adap,
+                               void *client, u32 chan)
+{
+        struct pca954x *data = i2c_get_clientdata(client);
+        const struct chip_desc *chip = &chips[data->type];
+        u8 regval;
+        int ret = 0;
+
+        /* we make switches look like muxes, not sure how to be smarter */
+        if (chip->muxtype == pca954x_ismux)
+                regval = chan | chip->enable;
+        else
+                regval = 1 << chan;
+
+        /* Only select the channel if its different from the last channel */
+        if (data->last_chan != regval) {
+                ret = pca954x_reg_write(adap, client, regval);
+                data->last_chan = regval;
+        }
+
+        return ret;
+}
+
+static int pca954x_deselect_mux(struct i2c_adapter *adap,
+                                void *client, u32 chan)
+{
+        struct pca954x *data = i2c_get_clientdata(client);
+
+        /* Deselect active channel */
+        data->last_chan = 0;
+        return pca954x_reg_write(adap, client, data->last_chan);
+}
+
+/*
+ * I2C init/probing/exit functions
+ */
+static int __devinit pca954x_probe(struct i2c_client *client,
+                                   const struct i2c_device_id *id)
+{
+        struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
+        struct pca954x_platform_data *pdata = client->dev.platform_data;
+        int num, force;
+        struct pca954x *data;
+        int ret = -ENODEV;
+
+        if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
+                goto err;
+
+        data = kzalloc(sizeof(struct pca954x), GFP_KERNEL);
+        if (!data) {
+                ret = -ENOMEM;
+                goto err;
+        }
+
+        i2c_set_clientdata(client, data);
+
+        /* Read the mux register at addr to verify
+         * that the mux is in fact present.
+         */
+        if (i2c_smbus_read_byte(client) < 0) {
+                dev_warn(&client->dev, "probe failed\n");
+                goto exit_free;
+        }
+
+        data->type = id->driver_data;
+        data->last_chan = 0;               /* force the first selection */
+
+        /* Now create an adapter for each channel */
+        for (num = 0; num < chips[data->type].nchans; num++) {
+                force = 0;                        /* dynamic adap number */
+                if (pdata) {
+                        if (num < pdata->num_modes)
+                                /* force static number */
+                                force = pdata->modes[num].adap_id;
+                        else
+                                /* discard unconfigured channels */
+                                break;
+                }
+
+                data->virt_adaps[num] =
+                        i2c_add_mux_adapter(adap, client,
+                                force, num, pca954x_select_chan,
+                                (pdata && pdata->modes[num].deselect_on_exit)
+                                        ? pca954x_deselect_mux : NULL);
+
+                if (data->virt_adaps[num] == NULL) {
+                        ret = -ENODEV;
+                        dev_err(&client->dev,
+                                "failed to register multiplexed adapter"
+                                " %d as bus %d\n", num, force);
+                        goto virt_reg_failed;
+                }
+        }
+
+        dev_info(&client->dev,
+                 "registered %d multiplexed busses for I2C %s %s\n",
+                 num, chips[data->type].muxtype == pca954x_ismux
+                                ? "mux" : "switch", client->name);
+
+        return 0;
+
+virt_reg_failed:
+        for (num--; num >= 0; num--)
+                i2c_del_mux_adapter(data->virt_adaps[num]);
+exit_free:
+        kfree(data);
+err:
+        return ret;
+}
+
+static int __devexit pca954x_remove(struct i2c_client *client)
+{
+        struct pca954x *data = i2c_get_clientdata(client);
+        const struct chip_desc *chip = &chips[data->type];
+        int i, err;
+
+        for (i = 0; i < chip->nchans; ++i)
+                if (data->virt_adaps[i]) {
+                        err = i2c_del_mux_adapter(data->virt_adaps[i]);
+                        if (err)
+                                return err;
+                        data->virt_adaps[i] = NULL;
+                }
+
+        kfree(data);
+        return 0;
+}
+
+static struct i2c_driver pca954x_driver = {
+        .driver         = {
+                .name   = "pca954x",
+                .owner  = THIS_MODULE,
+        },
+        .probe          = pca954x_probe,
+        .remove         = __devexit_p(pca954x_remove),
+        .id_table       = pca954x_id,
+};
+
+static int __init pca954x_init(void)
+{
+        return i2c_add_driver(&pca954x_driver);
+}
+
+static void __exit pca954x_exit(void)
+{
+        i2c_del_driver(&pca954x_driver);
+}
+
+module_init(pca954x_init);
+module_exit(pca954x_exit);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
+MODULE_LICENSE("GPL v2");