i2c: New bus driver for TI OMAP boards

i2c: New bus driver for TI OMAP boards

This patch adds I2C bus driver for various Texas
Instruments (TI) OMAP1/2 (http://www.ti.com/omap) series
based boards like OMAP1510/1610/1710/242x.

Signed-off-by: Komal Shah <komal_shah802003@yahoo.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 687 insertions, 0 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 404508ca7326..1df3bd97cb15 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -287,6 +287,16 @@ config I2C_OCORES
           This driver can also be built as a module.  If so, the module
           will be called i2c-ocores.
 
+config I2C_OMAP
+        tristate "OMAP I2C adapter"
+        depends on I2C && ARCH_OMAP
+        default y if MACH_OMAP_H3 || MACH_OMAP_OSK
+        help
+          If you say yes to this option, support will be included for the
+          I2C interface on the Texas Instruments OMAP1/2 family of processors.
+          Like OMAP1510/1610/1710/5912 and OMAP242x.
+          For details see http://www.ti.com/omap.
+
 config I2C_PARPORT
         tristate "Parallel port adapter"
         depends on I2C && PARPORT
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index ac56df53155b..493c87289b62 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_I2C_MPC)		+= i2c-mpc.o
 obj-$(CONFIG_I2C_MV64XXX)       += i2c-mv64xxx.o
 obj-$(CONFIG_I2C_NFORCE2)       += i2c-nforce2.o
 obj-$(CONFIG_I2C_OCORES)        += i2c-ocores.o
+obj-$(CONFIG_I2C_OMAP)          += i2c-omap.o
 obj-$(CONFIG_I2C_PARPORT)       += i2c-parport.o
 obj-$(CONFIG_I2C_PARPORT_LIGHT) += i2c-parport-light.o
 obj-$(CONFIG_I2C_PCA_ISA)       += i2c-pca-isa.o
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
new file mode 100644
index 000000000000..a129af991388
--- /dev/null
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -0,0 +1,676 @@
+/*
+ * TI OMAP I2C master mode driver
+ *
+ * Copyright (C) 2003 MontaVista Software, Inc.
+ * Copyright (C) 2004 Texas Instruments.
+ *
+ * Updated to work with multiple I2C interfaces on 24xx by
+ * Tony Lindgren <tony@atomide.com> and Imre Deak <imre.deak@nokia.com>
+ * Copyright (C) 2005 Nokia Corporation
+ *
+ * Cleaned up by Juha Yrjölä <juha.yrjola@nokia.com>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+
+#include <asm/io.h>
+
+/* timeout waiting for the controller to respond */
+#define OMAP_I2C_TIMEOUT (msecs_to_jiffies(1000))
+
+#define OMAP_I2C_REV_REG                0x00
+#define OMAP_I2C_IE_REG                 0x04
+#define OMAP_I2C_STAT_REG               0x08
+#define OMAP_I2C_IV_REG                 0x0c
+#define OMAP_I2C_SYSS_REG               0x10
+#define OMAP_I2C_BUF_REG                0x14
+#define OMAP_I2C_CNT_REG                0x18
+#define OMAP_I2C_DATA_REG               0x1c
+#define OMAP_I2C_SYSC_REG               0x20
+#define OMAP_I2C_CON_REG                0x24
+#define OMAP_I2C_OA_REG                 0x28
+#define OMAP_I2C_SA_REG                 0x2c
+#define OMAP_I2C_PSC_REG                0x30
+#define OMAP_I2C_SCLL_REG               0x34
+#define OMAP_I2C_SCLH_REG               0x38
+#define OMAP_I2C_SYSTEST_REG            0x3c
+
+/* I2C Interrupt Enable Register (OMAP_I2C_IE): */
+#define OMAP_I2C_IE_XRDY        (1 << 4)        /* TX data ready int enable */
+#define OMAP_I2C_IE_RRDY        (1 << 3)        /* RX data ready int enable */
+#define OMAP_I2C_IE_ARDY        (1 << 2)        /* Access ready int enable */
+#define OMAP_I2C_IE_NACK        (1 << 1)        /* No ack interrupt enable */
+#define OMAP_I2C_IE_AL          (1 << 0)        /* Arbitration lost int ena */
+
+/* I2C Status Register (OMAP_I2C_STAT): */
+#define OMAP_I2C_STAT_SBD       (1 << 15)       /* Single byte data */
+#define OMAP_I2C_STAT_BB        (1 << 12)       /* Bus busy */
+#define OMAP_I2C_STAT_ROVR      (1 << 11)       /* Receive overrun */
+#define OMAP_I2C_STAT_XUDF      (1 << 10)       /* Transmit underflow */
+#define OMAP_I2C_STAT_AAS       (1 << 9)        /* Address as slave */
+#define OMAP_I2C_STAT_AD0       (1 << 8)        /* Address zero */
+#define OMAP_I2C_STAT_XRDY      (1 << 4)        /* Transmit data ready */
+#define OMAP_I2C_STAT_RRDY      (1 << 3)        /* Receive data ready */
+#define OMAP_I2C_STAT_ARDY      (1 << 2)        /* Register access ready */
+#define OMAP_I2C_STAT_NACK      (1 << 1)        /* No ack interrupt enable */
+#define OMAP_I2C_STAT_AL        (1 << 0)        /* Arbitration lost int ena */
+
+/* I2C Buffer Configuration Register (OMAP_I2C_BUF): */
+#define OMAP_I2C_BUF_RDMA_EN    (1 << 15)       /* RX DMA channel enable */
+#define OMAP_I2C_BUF_XDMA_EN    (1 << 7)        /* TX DMA channel enable */
+
+/* I2C Configuration Register (OMAP_I2C_CON): */
+#define OMAP_I2C_CON_EN         (1 << 15)       /* I2C module enable */
+#define OMAP_I2C_CON_BE         (1 << 14)       /* Big endian mode */
+#define OMAP_I2C_CON_STB        (1 << 11)       /* Start byte mode (master) */
+#define OMAP_I2C_CON_MST        (1 << 10)       /* Master/slave mode */
+#define OMAP_I2C_CON_TRX        (1 << 9)        /* TX/RX mode (master only) */
+#define OMAP_I2C_CON_XA         (1 << 8)        /* Expand address */
+#define OMAP_I2C_CON_RM         (1 << 2)        /* Repeat mode (master only) */
+#define OMAP_I2C_CON_STP        (1 << 1)        /* Stop cond (master only) */
+#define OMAP_I2C_CON_STT        (1 << 0)        /* Start condition (master) */
+
+/* I2C System Test Register (OMAP_I2C_SYSTEST): */
+#ifdef DEBUG
+#define OMAP_I2C_SYSTEST_ST_EN          (1 << 15)       /* System test enable */
+#define OMAP_I2C_SYSTEST_FREE           (1 << 14)       /* Free running mode */
+#define OMAP_I2C_SYSTEST_TMODE_MASK     (3 << 12)       /* Test mode select */
+#define OMAP_I2C_SYSTEST_TMODE_SHIFT    (12)            /* Test mode select */
+#define OMAP_I2C_SYSTEST_SCL_I          (1 << 3)        /* SCL line sense in */
+#define OMAP_I2C_SYSTEST_SCL_O          (1 << 2)        /* SCL line drive out */
+#define OMAP_I2C_SYSTEST_SDA_I          (1 << 1)        /* SDA line sense in */
+#define OMAP_I2C_SYSTEST_SDA_O          (1 << 0)        /* SDA line drive out */
+#endif
+
+/* I2C System Status register (OMAP_I2C_SYSS): */
+#define OMAP_I2C_SYSS_RDONE             (1 << 0)        /* Reset Done */
+
+/* I2C System Configuration Register (OMAP_I2C_SYSC): */
+#define OMAP_I2C_SYSC_SRST              (1 << 1)        /* Soft Reset */
+
+/* REVISIT: Use platform_data instead of module parameters */
+/* Fast Mode = 400 kHz, Standard = 100 kHz */
+static int clock = 100; /* Default: 100 kHz */
+module_param(clock, int, 0);
+MODULE_PARM_DESC(clock, "Set I2C clock in kHz: 400=fast mode (default == 100)");
+
+struct omap_i2c_dev {
+        struct device           *dev;
+        void __iomem            *base;          /* virtual */
+        int                     irq;
+        struct clk              *iclk;          /* Interface clock */
+        struct clk              *fclk;          /* Functional clock */
+        struct completion       cmd_complete;
+        struct resource         *ioarea;
+        u16                     cmd_err;
+        u8                      *buf;
+        size_t                  buf_len;
+        struct i2c_adapter      adapter;
+        unsigned                rev1:1;
+};
+
+static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
+                                      int reg, u16 val)
+{
+        __raw_writew(val, i2c_dev->base + reg);
+}
+
+static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
+{
+        return __raw_readw(i2c_dev->base + reg);
+}
+
+static int omap_i2c_get_clocks(struct omap_i2c_dev *dev)
+{
+        if (cpu_is_omap16xx() || cpu_is_omap24xx()) {
+                dev->iclk = clk_get(dev->dev, "i2c_ick");
+                if (IS_ERR(dev->iclk)) {
+                        dev->iclk = NULL;
+                        return -ENODEV;
+                }
+        }
+
+        dev->fclk = clk_get(dev->dev, "i2c_fck");
+        if (IS_ERR(dev->fclk)) {
+                if (dev->iclk != NULL) {
+                        clk_put(dev->iclk);
+                        dev->iclk = NULL;
+                }
+                dev->fclk = NULL;
+                return -ENODEV;
+        }
+
+        return 0;
+}
+
+static void omap_i2c_put_clocks(struct omap_i2c_dev *dev)
+{
+        clk_put(dev->fclk);
+        dev->fclk = NULL;
+        if (dev->iclk != NULL) {
+                clk_put(dev->iclk);
+                dev->iclk = NULL;
+        }
+}
+
+static void omap_i2c_enable_clocks(struct omap_i2c_dev *dev)
+{
+        if (dev->iclk != NULL)
+                clk_enable(dev->iclk);
+        clk_enable(dev->fclk);
+}
+
+static void omap_i2c_disable_clocks(struct omap_i2c_dev *dev)
+{
+        if (dev->iclk != NULL)
+                clk_disable(dev->iclk);
+        clk_disable(dev->fclk);
+}
+
+static int omap_i2c_init(struct omap_i2c_dev *dev)
+{
+        u16 psc = 0;
+        unsigned long fclk_rate = 12000000;
+        unsigned long timeout;
+
+        if (!dev->rev1) {
+                omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, OMAP_I2C_SYSC_SRST);
+                /* For some reason we need to set the EN bit before the
+                 * reset done bit gets set. */
+                timeout = jiffies + OMAP_I2C_TIMEOUT;
+                omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
+                while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
+                         OMAP_I2C_SYSS_RDONE)) {
+                        if (time_after(jiffies, timeout)) {
+                                dev_warn(dev->dev, "timeout waiting"
+                                                "for controller reset\n");
+                                return -ETIMEDOUT;
+                        }
+                        msleep(1);
+                }
+        }
+        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
+
+        if (cpu_class_is_omap1()) {
+                struct clk *armxor_ck;
+
+                armxor_ck = clk_get(NULL, "armxor_ck");
+                if (IS_ERR(armxor_ck))
+                        dev_warn(dev->dev, "Could not get armxor_ck\n");
+                else {
+                        fclk_rate = clk_get_rate(armxor_ck);
+                        clk_put(armxor_ck);
+                }
+                /* TRM for 5912 says the I2C clock must be prescaled to be
+                 * between 7 - 12 MHz. The XOR input clock is typically
+                 * 12, 13 or 19.2 MHz. So we should have code that produces:
+                 *
+                 * XOR MHz      Divider         Prescaler
+                 * 12           1               0
+                 * 13           2               1
+                 * 19.2         2               1
+                 */
+                if (fclk_rate > 16000000)
+                        psc = (fclk_rate + 8000000) / 12000000;
+        }
+
+        /* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
+        omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);
+
+        /* Program desired operating rate */
+        fclk_rate /= (psc + 1) * 1000;
+        if (psc > 2)
+                psc = 2;
+
+        omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG,
+                           fclk_rate / (clock * 2) - 7 + psc);
+        omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG,
+                           fclk_rate / (clock * 2) - 7 + psc);
+
+        /* Take the I2C module out of reset: */
+        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
+
+        /* Enable interrupts */
+        omap_i2c_write_reg(dev, OMAP_I2C_IE_REG,
+                           (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
+                            OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
+                            OMAP_I2C_IE_AL));
+        return 0;
+}
+
+/*
+ * Waiting on Bus Busy
+ */
+static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev)
+{
+        unsigned long timeout;
+
+        timeout = jiffies + OMAP_I2C_TIMEOUT;
+        while (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) {
+                if (time_after(jiffies, timeout)) {
+                        dev_warn(dev->dev, "timeout waiting for bus ready\n");
+                        return -ETIMEDOUT;
+                }
+                msleep(1);
+        }
+
+        return 0;
+}
+
+/*
+ * Low level master read/write transaction.
+ */
+static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
+                             struct i2c_msg *msg, int stop)
+{
+        struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
+        int r;
+        u16 w;
+
+        dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
+                msg->addr, msg->len, msg->flags, stop);
+
+        if (msg->len == 0)
+                return -EINVAL;
+
+        omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);
+
+        /* REVISIT: Could the STB bit of I2C_CON be used with probing? */
+        dev->buf = msg->buf;
+        dev->buf_len = msg->len;
+
+        omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);
+
+        init_completion(&dev->cmd_complete);
+        dev->cmd_err = 0;
+
+        w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
+        if (msg->flags & I2C_M_TEN)
+                w |= OMAP_I2C_CON_XA;
+        if (!(msg->flags & I2C_M_RD))
+                w |= OMAP_I2C_CON_TRX;
+        if (stop)
+                w |= OMAP_I2C_CON_STP;
+        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
+
+        r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
+                                                      OMAP_I2C_TIMEOUT);
+        dev->buf_len = 0;
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                dev_err(dev->dev, "controller timed out\n");
+                omap_i2c_init(dev);
+                return -ETIMEDOUT;
+        }
+
+        if (likely(!dev->cmd_err))
+                return 0;
+
+        /* We have an error */
+        if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
+                            OMAP_I2C_STAT_XUDF)) {
+                omap_i2c_init(dev);
+                return -EIO;
+        }
+
+        if (dev->cmd_err & OMAP_I2C_STAT_NACK) {
+                if (msg->flags & I2C_M_IGNORE_NAK)
+                        return 0;
+                if (stop) {
+                        w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
+                        w |= OMAP_I2C_CON_STP;
+                        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
+                }
+                return -EREMOTEIO;
+        }
+        return -EIO;
+}
+
+
+/*
+ * Prepare controller for a transaction and call omap_i2c_xfer_msg
+ * to do the work during IRQ processing.
+ */
+static int
+omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+        struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
+        int i;
+        int r;
+
+        omap_i2c_enable_clocks(dev);
+
+        /* REVISIT: initialize and use adap->retries. This is an optional
+         * feature */
+        if ((r = omap_i2c_wait_for_bb(dev)) < 0)
+                goto out;
+
+        for (i = 0; i < num; i++) {
+                r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
+                if (r != 0)
+                        break;
+        }
+
+        if (r == 0)
+                r = num;
+out:
+        omap_i2c_disable_clocks(dev);
+        return r;
+}
+
+static u32
+omap_i2c_func(struct i2c_adapter *adap)
+{
+        return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+static inline void
+omap_i2c_complete_cmd(struct omap_i2c_dev *dev, u16 err)
+{
+        dev->cmd_err |= err;
+        complete(&dev->cmd_complete);
+}
+
+static inline void
+omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
+{
+        omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
+}
+
+static irqreturn_t
+omap_i2c_rev1_isr(int this_irq, void *dev_id, struct pt_regs *regs)
+{
+        struct omap_i2c_dev *dev = dev_id;
+        u16 iv, w;
+
+        iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
+        switch (iv) {
+        case 0x00:      /* None */
+                break;
+        case 0x01:      /* Arbitration lost */
+                dev_err(dev->dev, "Arbitration lost\n");
+                omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
+                break;
+        case 0x02:      /* No acknowledgement */
+                omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
+                omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP);
+                break;
+        case 0x03:      /* Register access ready */
+                omap_i2c_complete_cmd(dev, 0);
+                break;
+        case 0x04:      /* Receive data ready */
+                if (dev->buf_len) {
+                        w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
+                        *dev->buf++ = w;
+                        dev->buf_len--;
+                        if (dev->buf_len) {
+                                *dev->buf++ = w >> 8;
+                                dev->buf_len--;
+                        }
+                } else
+                        dev_err(dev->dev, "RRDY IRQ while no data requested\n");
+                break;
+        case 0x05:      /* Transmit data ready */
+                if (dev->buf_len) {
+                        w = *dev->buf++;
+                        dev->buf_len--;
+                        if (dev->buf_len) {
+                                w |= *dev->buf++ << 8;
+                                dev->buf_len--;
+                        }
+                        omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
+                } else
+                        dev_err(dev->dev, "XRDY IRQ while no data to send\n");
+                break;
+        default:
+                return IRQ_NONE;
+        }
+
+        return IRQ_HANDLED;
+}
+
+static irqreturn_t
+omap_i2c_isr(int this_irq, void *dev_id, struct pt_regs *regs)
+{
+        struct omap_i2c_dev *dev = dev_id;
+        u16 bits;
+        u16 stat, w;
+        int count = 0;
+
+        bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
+        while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
+                dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
+                if (count++ == 100) {
+                        dev_warn(dev->dev, "Too much work in one IRQ\n");
+                        break;
+                }
+
+                omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
+
+                if (stat & OMAP_I2C_STAT_ARDY) {
+                        omap_i2c_complete_cmd(dev, 0);
+                        continue;
+                }
+                if (stat & OMAP_I2C_STAT_RRDY) {
+                        w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
+                        if (dev->buf_len) {
+                                *dev->buf++ = w;
+                                dev->buf_len--;
+                                if (dev->buf_len) {
+                                        *dev->buf++ = w >> 8;
+                                        dev->buf_len--;
+                                }
+                        } else
+                                dev_err(dev->dev, "RRDY IRQ while no data"
+                                                "requested\n");
+                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RRDY);
+                        continue;
+                }
+                if (stat & OMAP_I2C_STAT_XRDY) {
+                        w = 0;
+                        if (dev->buf_len) {
+                                w = *dev->buf++;
+                                dev->buf_len--;
+                                if (dev->buf_len) {
+                                        w |= *dev->buf++ << 8;
+                                        dev->buf_len--;
+                                }
+                        } else
+                                dev_err(dev->dev, "XRDY IRQ while no"
+                                        "data to send\n");
+                        omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
+                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_XRDY);
+                        continue;
+                }
+                if (stat & OMAP_I2C_STAT_ROVR) {
+                        dev_err(dev->dev, "Receive overrun\n");
+                        dev->cmd_err |= OMAP_I2C_STAT_ROVR;
+                }
+                if (stat & OMAP_I2C_STAT_XUDF) {
+                        dev_err(dev->dev, "Transmit overflow\n");
+                        dev->cmd_err |= OMAP_I2C_STAT_XUDF;
+                }
+                if (stat & OMAP_I2C_STAT_NACK) {
+                        omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
+                        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
+                                           OMAP_I2C_CON_STP);
+                }
+                if (stat & OMAP_I2C_STAT_AL) {
+                        dev_err(dev->dev, "Arbitration lost\n");
+                        omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
+                }
+        }
+
+        return count ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static struct i2c_algorithm omap_i2c_algo = {
+        .master_xfer    = omap_i2c_xfer,
+        .functionality  = omap_i2c_func,
+};
+
+static int
+omap_i2c_probe(struct platform_device *pdev)
+{
+        struct omap_i2c_dev     *dev;
+        struct i2c_adapter      *adap;
+        struct resource         *mem, *irq, *ioarea;
+        int r;
+
+        /* NOTE: driver uses the static register mapping */
+        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!mem) {
+                dev_err(&pdev->dev, "no mem resource?\n");
+                return -ENODEV;
+        }
+        irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+        if (!irq) {
+                dev_err(&pdev->dev, "no irq resource?\n");
+                return -ENODEV;
+        }
+
+        ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
+                        pdev->name);
+        if (!ioarea) {
+                dev_err(&pdev->dev, "I2C region already claimed\n");
+                return -EBUSY;
+        }
+
+        if (clock > 200)
+                clock = 400;    /* Fast mode */
+        else
+                clock = 100;    /* Standard mode */
+
+        dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL);
+        if (!dev) {
+                r = -ENOMEM;
+                goto err_release_region;
+        }
+
+        dev->dev = &pdev->dev;
+        dev->irq = irq->start;
+        dev->base = (void __iomem *) IO_ADDRESS(mem->start);
+        platform_set_drvdata(pdev, dev);
+
+        if ((r = omap_i2c_get_clocks(dev)) != 0)
+                goto err_free_mem;
+
+        omap_i2c_enable_clocks(dev);
+
+        if (cpu_is_omap15xx())
+                dev->rev1 = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) < 0x20;
+
+        /* reset ASAP, clearing any IRQs */
+        omap_i2c_init(dev);
+
+        r = request_irq(dev->irq, dev->rev1 ? omap_i2c_rev1_isr : omap_i2c_isr,
+                        0, pdev->name, dev);
+
+        if (r) {
+                dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
+                goto err_unuse_clocks;
+        }
+        r = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
+        dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n",
+                 pdev->id, r >> 4, r & 0xf, clock);
+
+        adap = &dev->adapter;
+        i2c_set_adapdata(adap, dev);
+        adap->owner = THIS_MODULE;
+        adap->class = I2C_CLASS_HWMON;
+        strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
+        adap->algo = &omap_i2c_algo;
+        adap->dev.parent = &pdev->dev;
+
+        /* i2c device drivers may be active on return from add_adapter() */
+        r = i2c_add_adapter(adap);
+        if (r) {
+                dev_err(dev->dev, "failure adding adapter\n");
+                goto err_free_irq;
+        }
+
+        omap_i2c_disable_clocks(dev);
+
+        return 0;
+
+err_free_irq:
+        free_irq(dev->irq, dev);
+err_unuse_clocks:
+        omap_i2c_disable_clocks(dev);
+        omap_i2c_put_clocks(dev);
+err_free_mem:
+        platform_set_drvdata(pdev, NULL);
+        kfree(dev);
+err_release_region:
+        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
+        release_mem_region(mem->start, (mem->end - mem->start) + 1);
+
+        return r;
+}
+
+static int
+omap_i2c_remove(struct platform_device *pdev)
+{
+        struct omap_i2c_dev     *dev = platform_get_drvdata(pdev);
+        struct resource         *mem;
+
+        platform_set_drvdata(pdev, NULL);
+
+        free_irq(dev->irq, dev);
+        i2c_del_adapter(&dev->adapter);
+        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
+        omap_i2c_put_clocks(dev);
+        kfree(dev);
+        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        release_mem_region(mem->start, (mem->end - mem->start) + 1);
+        return 0;
+}
+
+static struct platform_driver omap_i2c_driver = {
+        .probe          = omap_i2c_probe,
+        .remove         = omap_i2c_remove,
+        .driver         = {
+                .name   = "i2c_omap",
+                .owner  = THIS_MODULE,
+        },
+};
+
+/* I2C may be needed to bring up other drivers */
+static int __init
+omap_i2c_init_driver(void)
+{
+        return platform_driver_register(&omap_i2c_driver);
+}
+subsys_initcall(omap_i2c_init_driver);
+
+static void __exit omap_i2c_exit_driver(void)
+{
+        platform_driver_unregister(&omap_i2c_driver);
+}
+module_exit(omap_i2c_exit_driver);
+
+MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
+MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
+MODULE_LICENSE("GPL");