/*
 * TI OMAP I2C master mode driver
 *
 * Copyright (C) 2003 MontaVista Software, Inc.
 * Copyright (C) 2005 Nokia Corporation
 * Copyright (C) 2004 - 2007 Texas Instruments.
 *
 * Originally written by MontaVista Software, Inc.
 * Additional contributions by:
 *      Tony Lindgren <tony@atomide.com>
 *      Imre Deak <imre.deak@nokia.com>
 *      Juha Yrjölä <juha.yrjola@solidboot.com>
 *      Syed Khasim <x0khasim@ti.com>
 *      Nishant Menon <nm@ti.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 <linux/io.h>
#include <linux/of.h>
#include <linux/of_i2c.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/i2c-omap.h>
#include <linux/pm_runtime.h>
#include <linux/pinctrl/consumer.h>

/* I2C controller revisions */
#define OMAP_I2C_OMAP1_REV_2            0x20

/* I2C controller revisions present on specific hardware */
#define OMAP_I2C_REV_ON_2430            0x00000036
#define OMAP_I2C_REV_ON_3430_3530       0x0000003C
#define OMAP_I2C_REV_ON_3630            0x00000040
#define OMAP_I2C_REV_ON_4430_PLUS       0x50400002

/* timeout waiting for the controller to respond */
#define OMAP_I2C_TIMEOUT (msecs_to_jiffies(1000))

/* timeout for pm runtime autosuspend */
#define OMAP_I2C_PM_TIMEOUT             1000    /* ms */

/* For OMAP3 I2C_IV has changed to I2C_WE (wakeup enable) */
enum {
        OMAP_I2C_REV_REG = 0,
        OMAP_I2C_IE_REG,
        OMAP_I2C_STAT_REG,
        OMAP_I2C_IV_REG,
        OMAP_I2C_WE_REG,
        OMAP_I2C_SYSS_REG,
        OMAP_I2C_BUF_REG,
        OMAP_I2C_CNT_REG,
        OMAP_I2C_DATA_REG,
        OMAP_I2C_SYSC_REG,
        OMAP_I2C_CON_REG,
        OMAP_I2C_OA_REG,
        OMAP_I2C_SA_REG,
        OMAP_I2C_PSC_REG,
        OMAP_I2C_SCLL_REG,
        OMAP_I2C_SCLH_REG,
        OMAP_I2C_SYSTEST_REG,
        OMAP_I2C_BUFSTAT_REG,
        /* only on OMAP4430 */
        OMAP_I2C_IP_V2_REVNB_LO,
        OMAP_I2C_IP_V2_REVNB_HI,
        OMAP_I2C_IP_V2_IRQSTATUS_RAW,
        OMAP_I2C_IP_V2_IRQENABLE_SET,
        OMAP_I2C_IP_V2_IRQENABLE_CLR,
};

/* I2C Interrupt Enable Register (OMAP_I2C_IE): */
#define OMAP_I2C_IE_XDR         (1 << 14)       /* TX Buffer drain int enable */
#define OMAP_I2C_IE_RDR         (1 << 13)       /* RX Buffer drain int enable */
#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_XDR       (1 << 14)       /* TX Buffer draining */
#define OMAP_I2C_STAT_RDR       (1 << 13)       /* RX Buffer draining */
#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 WE wakeup enable register */
#define OMAP_I2C_WE_XDR_WE      (1 << 14)       /* TX drain wakup */
#define OMAP_I2C_WE_RDR_WE      (1 << 13)       /* RX drain wakeup */
#define OMAP_I2C_WE_AAS_WE      (1 << 9)        /* Address as slave wakeup*/
#define OMAP_I2C_WE_BF_WE       (1 << 8)        /* Bus free wakeup */
#define OMAP_I2C_WE_STC_WE      (1 << 6)        /* Start condition wakeup */
#define OMAP_I2C_WE_GC_WE       (1 << 5)        /* General call wakeup */
#define OMAP_I2C_WE_DRDY_WE     (1 << 3)        /* TX/RX data ready wakeup */
#define OMAP_I2C_WE_ARDY_WE     (1 << 2)        /* Reg access ready wakeup */
#define OMAP_I2C_WE_NACK_WE     (1 << 1)        /* No acknowledgment wakeup */
#define OMAP_I2C_WE_AL_WE       (1 << 0)        /* Arbitration lost wakeup */

#define OMAP_I2C_WE_ALL         (OMAP_I2C_WE_XDR_WE | OMAP_I2C_WE_RDR_WE | \
                                OMAP_I2C_WE_AAS_WE | OMAP_I2C_WE_BF_WE | \
                                OMAP_I2C_WE_STC_WE | OMAP_I2C_WE_GC_WE | \
                                OMAP_I2C_WE_DRDY_WE | OMAP_I2C_WE_ARDY_WE | \
                                OMAP_I2C_WE_NACK_WE | OMAP_I2C_WE_AL_WE)

/* I2C Buffer Configuration Register (OMAP_I2C_BUF): */
#define OMAP_I2C_BUF_RDMA_EN    (1 << 15)       /* RX DMA channel enable */
#define OMAP_I2C_BUF_RXFIF_CLR  (1 << 14)       /* RX FIFO Clear */
#define OMAP_I2C_BUF_XDMA_EN    (1 << 7)        /* TX DMA channel enable */
#define OMAP_I2C_BUF_TXFIF_CLR  (1 << 6)        /* TX FIFO Clear */

/* 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_OPMODE_HS  (1 << 12)       /* High Speed support */
#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 SCL time value when Master */
#define OMAP_I2C_SCLL_HSSCLL    8
#define OMAP_I2C_SCLH_HSSCLH    8

/* 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

/* OCP_SYSSTATUS bit definitions */
#define SYSS_RESETDONE_MASK             (1 << 0)

/* OCP_SYSCONFIG bit definitions */
#define SYSC_CLOCKACTIVITY_MASK         (0x3 << 8)
#define SYSC_SIDLEMODE_MASK             (0x3 << 3)
#define SYSC_ENAWAKEUP_MASK             (1 << 2)
#define SYSC_SOFTRESET_MASK             (1 << 1)
#define SYSC_AUTOIDLE_MASK              (1 << 0)

#define SYSC_IDLEMODE_SMART             0x2
#define SYSC_CLOCKACTIVITY_FCLK         0x2

/* Errata definitions */
#define I2C_OMAP_ERRATA_I207            (1 << 0)
#define I2C_OMAP_ERRATA_I462            (1 << 1)

struct omap_i2c_dev {
        spinlock_t              lock;           /* IRQ synchronization */
        struct device           *dev;
        void __iomem            *base;          /* virtual */
        int                     irq;
        int                     reg_shift;      /* bit shift for I2C register addresses */
        struct completion       cmd_complete;
        struct resource         *ioarea;
        u32                     latency;        /* maximum mpu wkup latency */
        void                    (*set_mpu_wkup_lat)(struct device *dev,
                                                    long latency);
        u32                     speed;          /* Speed of bus in kHz */
        u32                     flags;
        u16                     cmd_err;
        u8                      *buf;
        u8                      *regs;
        size_t                  buf_len;
        struct i2c_adapter      adapter;
        u8                      threshold;
        u8                      fifo_size;      /* use as flag and value
                                                 * fifo_size==0 implies no fifo
                                                 * if set, should be trsh+1
                                                 */
        u32                     rev;
        unsigned                b_hw:1;         /* bad h/w fixes */
        unsigned                receiver:1;     /* true when we're in receiver mode */
        u16                     iestate;        /* Saved interrupt register */
        u16                     pscstate;
        u16                     scllstate;
        u16                     sclhstate;
        u16                     syscstate;
        u16                     westate;
        u16                     errata;

        struct pinctrl          *pins;
};

static const u8 reg_map_ip_v1[] = {
        [OMAP_I2C_REV_REG] = 0x00,
        [OMAP_I2C_IE_REG] = 0x01,
        [OMAP_I2C_STAT_REG] = 0x02,
        [OMAP_I2C_IV_REG] = 0x03,
        [OMAP_I2C_WE_REG] = 0x03,
        [OMAP_I2C_SYSS_REG] = 0x04,
        [OMAP_I2C_BUF_REG] = 0x05,
        [OMAP_I2C_CNT_REG] = 0x06,
        [OMAP_I2C_DATA_REG] = 0x07,
        [OMAP_I2C_SYSC_REG] = 0x08,
        [OMAP_I2C_CON_REG] = 0x09,
        [OMAP_I2C_OA_REG] = 0x0a,
        [OMAP_I2C_SA_REG] = 0x0b,
        [OMAP_I2C_PSC_REG] = 0x0c,
        [OMAP_I2C_SCLL_REG] = 0x0d,
        [OMAP_I2C_SCLH_REG] = 0x0e,
        [OMAP_I2C_SYSTEST_REG] = 0x0f,
        [OMAP_I2C_BUFSTAT_REG] = 0x10,
};

static const u8 reg_map_ip_v2[] = {
        [OMAP_I2C_REV_REG] = 0x04,
        [OMAP_I2C_IE_REG] = 0x2c,
        [OMAP_I2C_STAT_REG] = 0x28,
        [OMAP_I2C_IV_REG] = 0x34,
        [OMAP_I2C_WE_REG] = 0x34,
        [OMAP_I2C_SYSS_REG] = 0x90,
        [OMAP_I2C_BUF_REG] = 0x94,
        [OMAP_I2C_CNT_REG] = 0x98,
        [OMAP_I2C_DATA_REG] = 0x9c,
        [OMAP_I2C_SYSC_REG] = 0x10,
        [OMAP_I2C_CON_REG] = 0xa4,
        [OMAP_I2C_OA_REG] = 0xa8,
        [OMAP_I2C_SA_REG] = 0xac,
        [OMAP_I2C_PSC_REG] = 0xb0,
        [OMAP_I2C_SCLL_REG] = 0xb4,
        [OMAP_I2C_SCLH_REG] = 0xb8,
        [OMAP_I2C_SYSTEST_REG] = 0xbC,
        [OMAP_I2C_BUFSTAT_REG] = 0xc0,
        [OMAP_I2C_IP_V2_REVNB_LO] = 0x00,
        [OMAP_I2C_IP_V2_REVNB_HI] = 0x04,
        [OMAP_I2C_IP_V2_IRQSTATUS_RAW] = 0x24,
        [OMAP_I2C_IP_V2_IRQENABLE_SET] = 0x2c,
        [OMAP_I2C_IP_V2_IRQENABLE_CLR] = 0x30,
};

static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
                                      int reg, u16 val)
{
        __raw_writew(val, i2c_dev->base +
                        (i2c_dev->regs[reg] << i2c_dev->reg_shift));
}

static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
{
        return __raw_readw(i2c_dev->base +
                                (i2c_dev->regs[reg] << i2c_dev->reg_shift));
}

static void __omap_i2c_init(struct omap_i2c_dev *dev)
{

        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);

        /* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
        omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, dev->pscstate);

        /* SCL low and high time values */
        omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, dev->scllstate);
        omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, dev->sclhstate);
        if (dev->rev >= OMAP_I2C_REV_ON_3430_3530)
                omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate);

        /* Take the I2C module out of reset: */
        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);

        /*
         * Don't write to this register if the IE state is 0 as it can
         * cause deadlock.
         */
        if (dev->iestate)
                omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
}

static int omap_i2c_reset(struct omap_i2c_dev *dev)
{
        unsigned long timeout;
        u16 sysc;

        if (dev->rev >= OMAP_I2C_OMAP1_REV_2) {
                sysc = omap_i2c_read_reg(dev, OMAP_I2C_SYSC_REG);

                /* Disable I2C controller before soft reset */
                omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
                        omap_i2c_read_reg(dev, OMAP_I2C_CON_REG) &
                                ~(OMAP_I2C_CON_EN));

                omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, SYSC_SOFTRESET_MASK);
                /* 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) &
                         SYSS_RESETDONE_MASK)) {
                        if (time_after(jiffies, timeout)) {
                                dev_warn(dev->dev, "timeout waiting "
                                                "for controller reset\n");
                                return -ETIMEDOUT;
                        }
                        msleep(1);
                }

                /* SYSC register is cleared by the reset; rewrite it */
                omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, sysc);

        }
        return 0;
}

static int omap_i2c_init(struct omap_i2c_dev *dev)
{
        u16 psc = 0, scll = 0, sclh = 0;
        u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
        unsigned long fclk_rate = 12000000;
        unsigned long internal_clk = 0;
        struct clk *fclk;

        if (dev->rev >= OMAP_I2C_REV_ON_3430_3530) {
                /*
                 * Enabling all wakup sources to stop I2C freezing on
                 * WFI instruction.
                 * REVISIT: Some wkup sources might not be needed.
                 */
                dev->westate = OMAP_I2C_WE_ALL;
        }

        if (dev->flags & OMAP_I2C_FLAG_ALWAYS_ARMXOR_CLK) {
                /*
                 * The I2C functional clock is the armxor_ck, so there's
                 * no need to get "armxor_ck" separately.  Now, if OMAP2420
                 * always returns 12MHz for the functional clock, we can
                 * do this bit unconditionally.
                 */
                fclk = clk_get(dev->dev, "fck");
                fclk_rate = clk_get_rate(fclk);
                clk_put(fclk);

                /* 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 > 12000000)
                        psc = fclk_rate / 12000000;
        }

        if (!(dev->flags & OMAP_I2C_FLAG_SIMPLE_CLOCK)) {

                /*
                 * HSI2C controller internal clk rate should be 19.2 Mhz for
                 * HS and for all modes on 2430. On 34xx we can use lower rate
                 * to get longer filter period for better noise suppression.
                 * The filter is iclk (fclk for HS) period.
                 */
                if (dev->speed > 400 ||
                               dev->flags & OMAP_I2C_FLAG_FORCE_19200_INT_CLK)
                        internal_clk = 19200;
                else if (dev->speed > 100)
                        internal_clk = 9600;
                else
                        internal_clk = 4000;
                fclk = clk_get(dev->dev, "fck");
                fclk_rate = clk_get_rate(fclk) / 1000;
                clk_put(fclk);

                /* Compute prescaler divisor */
                psc = fclk_rate / internal_clk;
                psc = psc - 1;

                /* If configured for High Speed */
                if (dev->speed > 400) {
                        unsigned long scl;

                        /* For first phase of HS mode */
                        scl = internal_clk / 400;
                        fsscll = scl - (scl / 3) - 7;
                        fssclh = (scl / 3) - 5;

                        /* For second phase of HS mode */
                        scl = fclk_rate / dev->speed;
                        hsscll = scl - (scl / 3) - 7;
                        hssclh = (scl / 3) - 5;
                } else if (dev->speed > 100) {
                        unsigned long scl;

                        /* Fast mode */
                        scl = internal_clk / dev->speed;
                        fsscll = scl - (scl / 3) - 7;
                        fssclh = (scl / 3) - 5;
                } else {
                        /* Standard mode */
                        fsscll = internal_clk / (dev->speed * 2) - 7;
                        fssclh = internal_clk / (dev->speed * 2) - 5;
                }
                scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll;
                sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh;
        } else {
                /* Program desired operating rate */
                fclk_rate /= (psc + 1) * 1000;
                if (psc > 2)
                        psc = 2;
                scll = fclk_rate / (dev->speed * 2) - 7 + psc;
                sclh = fclk_rate / (dev->speed * 2) - 7 + psc;
        }

        dev->iestate = (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
                        OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
                        OMAP_I2C_IE_AL)  | ((dev->fifo_size) ?
                                (OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0);

        dev->pscstate = psc;
        dev->scllstate = scll;
        dev->sclhstate = sclh;

        __omap_i2c_init(dev);

        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;
}

static void omap_i2c_resize_fifo(struct omap_i2c_dev *dev, u8 size, bool is_rx)
{
        u16             buf;

        if (dev->flags & OMAP_I2C_FLAG_NO_FIFO)
                return;

        /*
         * Set up notification threshold based on message size. We're doing
         * this to try and avoid draining feature as much as possible. Whenever
         * we have big messages to transfer (bigger than our total fifo size)
         * then we might use draining feature to transfer the remaining bytes.
         */

        dev->threshold = clamp(size, (u8) 1, dev->fifo_size);

        buf = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);

        if (is_rx) {
                /* Clear RX Threshold */
                buf &= ~(0x3f << 8);
                buf |= ((dev->threshold - 1) << 8) | OMAP_I2C_BUF_RXFIF_CLR;
        } else {
                /* Clear TX Threshold */
                buf &= ~0x3f;
                buf |= (dev->threshold - 1) | OMAP_I2C_BUF_TXFIF_CLR;
        }

        omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf);

        if (dev->rev < OMAP_I2C_REV_ON_3630)
                dev->b_hw = 1; /* Enable hardware fixes */

        /* calculate wakeup latency constraint for MPU */
        if (dev->set_mpu_wkup_lat != NULL)
                dev->latency = (1000000 * dev->threshold) /
                        (1000 * dev->speed / 8);
}

/*
 * 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);
        unsigned long timeout;
        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;

        dev->receiver = !!(msg->flags & I2C_M_RD);
        omap_i2c_resize_fifo(dev, msg->len, dev->receiver);

        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;

        /* make sure writes to dev->buf_len are ordered */
        barrier();

        omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);

        /* Clear the FIFO Buffers */
        w = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);
        w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;
        omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, w);

        INIT_COMPLETION(dev->cmd_complete);
        dev->cmd_err = 0;

        w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;

        /* High speed configuration */
        if (dev->speed > 400)
                w |= OMAP_I2C_CON_OPMODE_HS;

        if (msg->flags & I2C_M_STOP)
                stop = 1;
        if (msg->flags & I2C_M_TEN)
                w |= OMAP_I2C_CON_XA;
        if (!(msg->flags & I2C_M_RD))
                w |= OMAP_I2C_CON_TRX;

        if (!dev->b_hw && stop)
                w |= OMAP_I2C_CON_STP;

        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);

        /*
         * Don't write stt and stp together on some hardware.
         */
        if (dev->b_hw && stop) {
                unsigned long delay = jiffies + OMAP_I2C_TIMEOUT;
                u16 con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
                while (con & OMAP_I2C_CON_STT) {
                        con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);

                        /* Let the user know if i2c is in a bad state */
                        if (time_after(jiffies, delay)) {
                                dev_err(dev->dev, "controller timed out "
                                "waiting for start condition to finish\n");
                                return -ETIMEDOUT;
                        }
                        cpu_relax();
                }

                w |= OMAP_I2C_CON_STP;
                w &= ~OMAP_I2C_CON_STT;
                omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
        }

        /*
         * REVISIT: We should abort the transfer on signals, but the bus goes
         * into arbitration and we're currently unable to recover from it.
         */
        timeout = wait_for_completion_timeout(&dev->cmd_complete,
                                                OMAP_I2C_TIMEOUT);
        if (timeout == 0) {
                dev_err(dev->dev, "controller timed out\n");
                omap_i2c_reset(dev);
                __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_reset(dev);
                __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;

        r = pm_runtime_get_sync(dev->dev);
        if (IS_ERR_VALUE(r))
                goto out;

        r = omap_i2c_wait_for_bb(dev);
        if (r < 0)
                goto out;

        if (dev->set_mpu_wkup_lat != NULL)
                dev->set_mpu_wkup_lat(dev->dev, dev->latency);

        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;

        omap_i2c_wait_for_bb(dev);

        if (dev->set_mpu_wkup_lat != NULL)
                dev->set_mpu_wkup_lat(dev->dev, -1);

out:
        pm_runtime_mark_last_busy(dev->dev);
        pm_runtime_put_autosuspend(dev->dev);
        return r;
}

static u32
omap_i2c_func(struct i2c_adapter *adap)
{
        return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
               I2C_FUNC_PROTOCOL_MANGLING;
}

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 inline void i2c_omap_errata_i207(struct omap_i2c_dev *dev, u16 stat)
{
        /*
         * I2C Errata(Errata Nos. OMAP2: 1.67, OMAP3: 1.8)
         * Not applicable for OMAP4.
         * Under certain rare conditions, RDR could be set again
         * when the bus is busy, then ignore the interrupt and
         * clear the interrupt.
         */
        if (stat & OMAP_I2C_STAT_RDR) {
                /* Step 1: If RDR is set, clear it */
                omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RDR);

                /* Step 2: */
                if (!(omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG)
                                                & OMAP_I2C_STAT_BB)) {

                        /* Step 3: */
                        if (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG)
                                                & OMAP_I2C_STAT_RDR) {
                                omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RDR);
                                dev_dbg(dev->dev, "RDR when bus is busy.\n");
                        }

                }
        }
}

/* rev1 devices are apparently only on some 15xx */
#ifdef CONFIG_ARCH_OMAP15XX

static irqreturn_t
omap_i2c_omap1_isr(int this_irq, void *dev_id)
{
        struct omap_i2c_dev *dev = dev_id;
        u16 iv, w;

        if (pm_runtime_suspended(dev->dev))
                return IRQ_NONE;

        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;
}
#else
#define omap_i2c_omap1_isr              NULL
#endif

/*
 * OMAP3430 Errata i462: When an XRDY/XDR is hit, wait for XUDF before writing
 * data to DATA_REG. Otherwise some data bytes can be lost while transferring
 * them from the memory to the I2C interface.
 */
static int errata_omap3_i462(struct omap_i2c_dev *dev)
{
        unsigned long timeout = 10000;
        u16 stat;

        do {
                stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
                if (stat & OMAP_I2C_STAT_XUDF)
                        break;

                if (stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
                        omap_i2c_ack_stat(dev, (OMAP_I2C_STAT_XRDY |
                                                        OMAP_I2C_STAT_XDR));
                        if (stat & OMAP_I2C_STAT_NACK) {
                                dev->cmd_err |= OMAP_I2C_STAT_NACK;
                                omap_i2c_ack_stat(dev, OMAP_I2C_STAT_NACK);
                        }

                        if (stat & OMAP_I2C_STAT_AL) {
                                dev_err(dev->dev, "Arbitration lost\n");
                                dev->cmd_err |= OMAP_I2C_STAT_AL;
                                omap_i2c_ack_stat(dev, OMAP_I2C_STAT_AL);
                        }

                        return -EIO;
                }

                cpu_relax();
        } while (--timeout);

        if (!timeout) {
                dev_err(dev->dev, "timeout waiting on XUDF bit\n");
                return 0;
        }

        return 0;
}

static void omap_i2c_receive_data(struct omap_i2c_dev *dev, u8 num_bytes,
                bool is_rdr)
{
        u16             w;

        while (num_bytes--) {
                w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
                *dev->buf++ = w;
                dev->buf_len--;

                /*
                 * Data reg in 2430, omap3 and
                 * omap4 is 8 bit wide
                 */
                if (dev->flags & OMAP_I2C_FLAG_16BIT_DATA_REG) {
                        *dev->buf++ = w >> 8;
                        dev->buf_len--;
                }
        }
}

static int omap_i2c_transmit_data(struct omap_i2c_dev *dev, u8 num_bytes,
                bool is_xdr)
{
        u16             w;

        while (num_bytes--) {
                w = *dev->buf++;
                dev->buf_len--;

                /*
                 * Data reg in 2430, omap3 and
                 * omap4 is 8 bit wide
                 */
                if (dev->flags & OMAP_I2C_FLAG_16BIT_DATA_REG) {
                        w |= *dev->buf++ << 8;
                        dev->buf_len--;
                }

                if (dev->errata & I2C_OMAP_ERRATA_I462) {
                        int ret;

                        ret = errata_omap3_i462(dev);
                        if (ret < 0)
                                return ret;
                }

                omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
        }

        return 0;
}

static irqreturn_t
omap_i2c_isr(int irq, void *dev_id)
{
        struct omap_i2c_dev *dev = dev_id;
        irqreturn_t ret = IRQ_HANDLED;
        u16 mask;
        u16 stat;

        spin_lock(&dev->lock);
        mask = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
        stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);

        if (stat & mask)
                ret = IRQ_WAKE_THREAD;

        spin_unlock(&dev->lock);

        return ret;
}

static irqreturn_t
omap_i2c_isr_thread(int this_irq, void *dev_id)
{
        struct omap_i2c_dev *dev = dev_id;
        unsigned long flags;
        u16 bits;
        u16 stat;
        int err = 0, count = 0;

        spin_lock_irqsave(&dev->lock, flags);
        do {
                bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
                stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
                stat &= bits;

                /* If we're in receiver mode, ignore XDR/XRDY */
                if (dev->receiver)
                        stat &= ~(OMAP_I2C_STAT_XDR | OMAP_I2C_STAT_XRDY);
                else
                        stat &= ~(OMAP_I2C_STAT_RDR | OMAP_I2C_STAT_RRDY);

                if (!stat) {
                        /* my work here is done */
                        goto out;
                }

                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;
                }

                if (stat & OMAP_I2C_STAT_NACK) {
                        err |= OMAP_I2C_STAT_NACK;
                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_NACK);
                        break;
                }

                if (stat & OMAP_I2C_STAT_AL) {
                        dev_err(dev->dev, "Arbitration lost\n");
                        err |= OMAP_I2C_STAT_AL;
                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_AL);
                        break;
                }

                /*
                 * ProDB0017052: Clear ARDY bit twice
                 */
                if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
                                        OMAP_I2C_STAT_AL)) {
                        omap_i2c_ack_stat(dev, (OMAP_I2C_STAT_RRDY |
                                                OMAP_I2C_STAT_RDR |
                                                OMAP_I2C_STAT_XRDY |
                                                OMAP_I2C_STAT_XDR |
                                                OMAP_I2C_STAT_ARDY));
                        break;
                }

                if (stat & OMAP_I2C_STAT_RDR) {
                        u8 num_bytes = 1;

                        if (dev->fifo_size)
                                num_bytes = dev->buf_len;

                        omap_i2c_receive_data(dev, num_bytes, true);

                        if (dev->errata & I2C_OMAP_ERRATA_I207)
                                i2c_omap_errata_i207(dev, stat);

                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RDR);
                        continue;
                }

                if (stat & OMAP_I2C_STAT_RRDY) {
                        u8 num_bytes = 1;

                        if (dev->threshold)
                                num_bytes = dev->threshold;

                        omap_i2c_receive_data(dev, num_bytes, false);
                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RRDY);
                        continue;
                }

                if (stat & OMAP_I2C_STAT_XDR) {
                        u8 num_bytes = 1;
                        int ret;

                        if (dev->fifo_size)
                                num_bytes = dev->buf_len;

                        ret = omap_i2c_transmit_data(dev, num_bytes, true);
                        if (ret < 0)
                                break;

                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_XDR);
                        continue;
                }

                if (stat & OMAP_I2C_STAT_XRDY) {
                        u8 num_bytes = 1;
                        int ret;

                        if (dev->threshold)
                                num_bytes = dev->threshold;

                        ret = omap_i2c_transmit_data(dev, num_bytes, false);
                        if (ret < 0)
                                break;

                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_XRDY);
                        continue;
                }

                if (stat & OMAP_I2C_STAT_ROVR) {
                        dev_err(dev->dev, "Receive overrun\n");
                        err |= OMAP_I2C_STAT_ROVR;
                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_ROVR);
                        break;
                }

                if (stat & OMAP_I2C_STAT_XUDF) {
                        dev_err(dev->dev, "Transmit underflow\n");
                        err |= OMAP_I2C_STAT_XUDF;
                        omap_i2c_ack_stat(dev, OMAP_I2C_STAT_XUDF);
                        break;
                }
        } while (stat);

        omap_i2c_complete_cmd(dev, err);

out:
        spin_unlock_irqrestore(&dev->lock, flags);

        return IRQ_HANDLED;
}

static const struct i2c_algorithm omap_i2c_algo = {
        .master_xfer    = omap_i2c_xfer,
        .functionality  = omap_i2c_func,
};

#ifdef CONFIG_OF
static struct omap_i2c_bus_platform_data omap3_pdata = {
        .rev = OMAP_I2C_IP_VERSION_1,
        .flags = OMAP_I2C_FLAG_BUS_SHIFT_2,
};

static struct omap_i2c_bus_platform_data omap4_pdata = {
        .rev = OMAP_I2C_IP_VERSION_2,
};

static const struct of_device_id omap_i2c_of_match[] = {
        {
                .compatible = "ti,omap4-i2c",
                .data = &omap4_pdata,
        },
        {
                .compatible = "ti,omap3-i2c",
                .data = &omap3_pdata,
        },
        { },
};
MODULE_DEVICE_TABLE(of, omap_i2c_of_match);
#endif

#define OMAP_I2C_SCHEME(rev)            ((rev & 0xc000) >> 14)

#define OMAP_I2C_REV_SCHEME_0_MAJOR(rev) (rev >> 4)
#define OMAP_I2C_REV_SCHEME_0_MINOR(rev) (rev & 0xf)

#define OMAP_I2C_REV_SCHEME_1_MAJOR(rev) ((rev & 0x0700) >> 7)
#define OMAP_I2C_REV_SCHEME_1_MINOR(rev) (rev & 0x1f)
#define OMAP_I2C_SCHEME_0               0
#define OMAP_I2C_SCHEME_1               1

static int
omap_i2c_probe(struct platform_device *pdev)
{
        struct omap_i2c_dev     *dev;
        struct i2c_adapter      *adap;
        struct resource         *mem;
        const struct omap_i2c_bus_platform_data *pdata =
                pdev->dev.platform_data;
        struct device_node      *node = pdev->dev.of_node;
        const struct of_device_id *match;
        int irq;
        int r;
        u32 rev;
        u16 minor, major, scheme;

        /* 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_irq(pdev, 0);
        if (irq < 0) {
                dev_err(&pdev->dev, "no irq resource?\n");
                return irq;
        }

        dev = devm_kzalloc(&pdev->dev, sizeof(struct omap_i2c_dev), GFP_KERNEL);
        if (!dev) {
                dev_err(&pdev->dev, "Menory allocation failed\n");
                return -ENOMEM;
        }

        dev->base = devm_ioremap_resource(&pdev->dev, mem);
        if (IS_ERR(dev->base))
                return PTR_ERR(dev->base);

        match = of_match_device(of_match_ptr(omap_i2c_of_match), &pdev->dev);
        if (match) {
                u32 freq = 100000; /* default to 100000 Hz */

                pdata = match->data;
                dev->flags = pdata->flags;

                of_property_read_u32(node, "clock-frequency", &freq);
                /* convert DT freq value in Hz into kHz for speed */
                dev->speed = freq / 1000;
        } else if (pdata != NULL) {
                dev->speed = pdata->clkrate;
                dev->flags = pdata->flags;
                dev->set_mpu_wkup_lat = pdata->set_mpu_wkup_lat;
        }

        dev->pins = devm_pinctrl_get_select_default(&pdev->dev);
        if (IS_ERR(dev->pins)) {
                if (PTR_ERR(dev->pins) == -EPROBE_DEFER)
                        return -EPROBE_DEFER;

                dev_warn(&pdev->dev, "did not get pins for i2c error: %li\n",
                         PTR_ERR(dev->pins));
                dev->pins = NULL;
        }

        dev->dev = &pdev->dev;
        dev->irq = irq;

        spin_lock_init(&dev->lock);

        platform_set_drvdata(pdev, dev);
        init_completion(&dev->cmd_complete);

        dev->reg_shift = (dev->flags >> OMAP_I2C_FLAG_BUS_SHIFT__SHIFT) & 3;

        pm_runtime_enable(dev->dev);
        pm_runtime_set_autosuspend_delay(dev->dev, OMAP_I2C_PM_TIMEOUT);
        pm_runtime_use_autosuspend(dev->dev);

        r = pm_runtime_get_sync(dev->dev);
        if (IS_ERR_VALUE(r))
                goto err_free_mem;

        /*
         * Read the Rev hi bit-[15:14] ie scheme this is 1 indicates ver2.
         * On omap1/3/2 Offset 4 is IE Reg the bit [15:14] is 0 at reset.
         * Also since the omap_i2c_read_reg uses reg_map_ip_* a
         * raw_readw is done.
         */
        rev = __raw_readw(dev->base + 0x04);

        scheme = OMAP_I2C_SCHEME(rev);
        switch (scheme) {
        case OMAP_I2C_SCHEME_0:
                dev->regs = (u8 *)reg_map_ip_v1;
                dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG);
                minor = OMAP_I2C_REV_SCHEME_0_MAJOR(dev->rev);
                major = OMAP_I2C_REV_SCHEME_0_MAJOR(dev->rev);
                break;
        case OMAP_I2C_SCHEME_1:
                /* FALLTHROUGH */
        default:
                dev->regs = (u8 *)reg_map_ip_v2;
                rev = (rev << 16) |
                        omap_i2c_read_reg(dev, OMAP_I2C_IP_V2_REVNB_LO);
                minor = OMAP_I2C_REV_SCHEME_1_MINOR(rev);
                major = OMAP_I2C_REV_SCHEME_1_MAJOR(rev);
                dev->rev = rev;
        }

        dev->errata = 0;

        if (dev->rev >= OMAP_I2C_REV_ON_2430 &&
                        dev->rev < OMAP_I2C_REV_ON_4430_PLUS)
                dev->errata |= I2C_OMAP_ERRATA_I207;

        if (dev->rev <= OMAP_I2C_REV_ON_3430_3530)
                dev->errata |= I2C_OMAP_ERRATA_I462;

        if (!(dev->flags & OMAP_I2C_FLAG_NO_FIFO)) {
                u16 s;

                /* Set up the fifo size - Get total size */
                s = (omap_i2c_read_reg(dev, OMAP_I2C_BUFSTAT_REG) >> 14) & 0x3;
                dev->fifo_size = 0x8 << s;

                /*
                 * Set up notification threshold as half the total available
                 * size. This is to ensure that we can handle the status on int
                 * call back latencies.
                 */

                dev->fifo_size = (dev->fifo_size / 2);

                if (dev->rev < OMAP_I2C_REV_ON_3630)
                        dev->b_hw = 1; /* Enable hardware fixes */

                /* calculate wakeup latency constraint for MPU */
                if (dev->set_mpu_wkup_lat != NULL)
                        dev->latency = (1000000 * dev->fifo_size) /
                                       (1000 * dev->speed / 8);
        }

        /* reset ASAP, clearing any IRQs */
        omap_i2c_init(dev);

        if (dev->rev < OMAP_I2C_OMAP1_REV_2)
                r = devm_request_irq(&pdev->dev, dev->irq, omap_i2c_omap1_isr,
                                IRQF_NO_SUSPEND, pdev->name, dev);
        else
                r = devm_request_threaded_irq(&pdev->dev, dev->irq,
                                omap_i2c_isr, omap_i2c_isr_thread,
                                IRQF_NO_SUSPEND | IRQF_ONESHOT,
                                pdev->name, dev);

        if (r) {
                dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
                goto err_unuse_clocks;
        }

        adap = &dev->adapter;
        i2c_set_adapdata(adap, dev);
        adap->owner = THIS_MODULE;
        adap->class = I2C_CLASS_HWMON;
        strlcpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
        adap->algo = &omap_i2c_algo;
        adap->dev.parent = &pdev->dev;
        adap->dev.of_node = pdev->dev.of_node;

        /* i2c device drivers may be active on return from add_adapter() */
        adap->nr = pdev->id;
        r = i2c_add_numbered_adapter(adap);
        if (r) {
                dev_err(dev->dev, "failure adding adapter\n");
                goto err_unuse_clocks;
        }

        dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n", adap->nr,
                 major, minor, dev->speed);

        of_i2c_register_devices(adap);

        pm_runtime_mark_last_busy(dev->dev);
        pm_runtime_put_autosuspend(dev->dev);

        return 0;

err_unuse_clocks:
        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
        pm_runtime_put(dev->dev);
        pm_runtime_disable(&pdev->dev);
err_free_mem:

        return r;
}

static int omap_i2c_remove(struct platform_device *pdev)
{
        struct omap_i2c_dev     *dev = platform_get_drvdata(pdev);
        int ret;

        i2c_del_adapter(&dev->adapter);
        ret = pm_runtime_get_sync(&pdev->dev);
        if (IS_ERR_VALUE(ret))
                return ret;

        omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
        pm_runtime_put(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        return 0;
}

#ifdef CONFIG_PM
#ifdef CONFIG_PM_RUNTIME
static int omap_i2c_runtime_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);

        _dev->iestate = omap_i2c_read_reg(_dev, OMAP_I2C_IE_REG);

        omap_i2c_write_reg(_dev, OMAP_I2C_IE_REG, 0);

        if (_dev->rev < OMAP_I2C_OMAP1_REV_2) {
                omap_i2c_read_reg(_dev, OMAP_I2C_IV_REG); /* Read clears */
        } else {
                omap_i2c_write_reg(_dev, OMAP_I2C_STAT_REG, _dev->iestate);

                /* Flush posted write */
                omap_i2c_read_reg(_dev, OMAP_I2C_STAT_REG);
        }

        return 0;
}

static int omap_i2c_runtime_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);

        if (!_dev->regs)
                return 0;

        __omap_i2c_init(_dev);

        return 0;
}
#endif /* CONFIG_PM_RUNTIME */

static struct dev_pm_ops omap_i2c_pm_ops = {
        SET_RUNTIME_PM_OPS(omap_i2c_runtime_suspend,
                           omap_i2c_runtime_resume, NULL)
};
#define OMAP_I2C_PM_OPS (&omap_i2c_pm_ops)
#else
#define OMAP_I2C_PM_OPS NULL
#endif /* CONFIG_PM */

static struct platform_driver omap_i2c_driver = {
        .probe          = omap_i2c_probe,
        .remove         = omap_i2c_remove,
        .driver         = {
                .name   = "omap_i2c",
                .owner  = THIS_MODULE,
                .pm     = OMAP_I2C_PM_OPS,
                .of_match_table = of_match_ptr(omap_i2c_of_match),
        },
};

/* 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");
MODULE_ALIAS("platform:omap_i2c");