1 files changed, 251 insertions, 63 deletions

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,
         },
 };