Linux 4.19.133

[linux/fpc-iii.git] / drivers / i2c / busses / i2c-designware-master.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Synopsys DesignWare I2C adapter driver (master only).
 *
 * Based on the TI DAVINCI I2C adapter driver.
 *
 * Copyright (C) 2006 Texas Instruments.
 * Copyright (C) 2007 MontaVista Software Inc.
 * Copyright (C) 2009 Provigent Ltd.
 */
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>

#include "i2c-designware-core.h"

static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
{
        /* Configure Tx/Rx FIFO threshold levels */
        dw_writel(dev, dev->tx_fifo_depth / 2, DW_IC_TX_TL);
        dw_writel(dev, 0, DW_IC_RX_TL);

        /* Configure the I2C master */
        dw_writel(dev, dev->master_cfg, DW_IC_CON);
}

static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
{
        const char *mode_str, *fp_str = "";
        u32 comp_param1;
        u32 sda_falling_time, scl_falling_time;
        struct i2c_timings *t = &dev->timings;
        u32 ic_clk;
        int ret;

        ret = i2c_dw_acquire_lock(dev);
        if (ret)
                return ret;
        comp_param1 = dw_readl(dev, DW_IC_COMP_PARAM_1);
        i2c_dw_release_lock(dev);

        /* Set standard and fast speed dividers for high/low periods */
        sda_falling_time = t->sda_fall_ns ?: 300; /* ns */
        scl_falling_time = t->scl_fall_ns ?: 300; /* ns */

        /* Calculate SCL timing parameters for standard mode if not set */
        if (!dev->ss_hcnt || !dev->ss_lcnt) {
                ic_clk = i2c_dw_clk_rate(dev);
                dev->ss_hcnt =
                        i2c_dw_scl_hcnt(ic_clk,
                                        4000,   /* tHD;STA = tHIGH = 4.0 us */
                                        sda_falling_time,
                                        0,      /* 0: DW default, 1: Ideal */
                                        0);     /* No offset */
                dev->ss_lcnt =
                        i2c_dw_scl_lcnt(ic_clk,
                                        4700,   /* tLOW = 4.7 us */
                                        scl_falling_time,
                                        0);     /* No offset */
        }
        dev_dbg(dev->dev, "Standard Mode HCNT:LCNT = %d:%d\n",
                dev->ss_hcnt, dev->ss_lcnt);

        /*
         * Set SCL timing parameters for fast mode or fast mode plus. Only
         * difference is the timing parameter values since the registers are
         * the same.
         */
        if (t->bus_freq_hz == 1000000) {
                /*
                 * Check are fast mode plus parameters available and use
                 * fast mode if not.
                 */
                if (dev->fp_hcnt && dev->fp_lcnt) {
                        dev->fs_hcnt = dev->fp_hcnt;
                        dev->fs_lcnt = dev->fp_lcnt;
                        fp_str = " Plus";
                }
        }
        /*
         * Calculate SCL timing parameters for fast mode if not set. They are
         * needed also in high speed mode.
         */
        if (!dev->fs_hcnt || !dev->fs_lcnt) {
                ic_clk = i2c_dw_clk_rate(dev);
                dev->fs_hcnt =
                        i2c_dw_scl_hcnt(ic_clk,
                                        600,    /* tHD;STA = tHIGH = 0.6 us */
                                        sda_falling_time,
                                        0,      /* 0: DW default, 1: Ideal */
                                        0);     /* No offset */
                dev->fs_lcnt =
                        i2c_dw_scl_lcnt(ic_clk,
                                        1300,   /* tLOW = 1.3 us */
                                        scl_falling_time,
                                        0);     /* No offset */
        }
        dev_dbg(dev->dev, "Fast Mode%s HCNT:LCNT = %d:%d\n",
                fp_str, dev->fs_hcnt, dev->fs_lcnt);

        /* Check is high speed possible and fall back to fast mode if not */
        if ((dev->master_cfg & DW_IC_CON_SPEED_MASK) ==
                DW_IC_CON_SPEED_HIGH) {
                if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK)
                        != DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH) {
                        dev_err(dev->dev, "High Speed not supported!\n");
                        dev->master_cfg &= ~DW_IC_CON_SPEED_MASK;
                        dev->master_cfg |= DW_IC_CON_SPEED_FAST;
                        dev->hs_hcnt = 0;
                        dev->hs_lcnt = 0;
                } else if (dev->hs_hcnt && dev->hs_lcnt) {
                        dev_dbg(dev->dev, "High Speed Mode HCNT:LCNT = %d:%d\n",
                                dev->hs_hcnt, dev->hs_lcnt);
                }
        }

        ret = i2c_dw_set_sda_hold(dev);
        if (ret)
                goto out;

        switch (dev->master_cfg & DW_IC_CON_SPEED_MASK) {
        case DW_IC_CON_SPEED_STD:
                mode_str = "Standard Mode";
                break;
        case DW_IC_CON_SPEED_HIGH:
                mode_str = "High Speed Mode";
                break;
        default:
                mode_str = "Fast Mode";
        }
        dev_dbg(dev->dev, "Bus speed: %s%s\n", mode_str, fp_str);

out:
        return ret;
}

/**
 * i2c_dw_init() - Initialize the designware I2C master hardware
 * @dev: device private data
 *
 * This functions configures and enables the I2C master.
 * This function is called during I2C init function, and in case of timeout at
 * run time.
 */
static int i2c_dw_init_master(struct dw_i2c_dev *dev)
{
        int ret;

        ret = i2c_dw_acquire_lock(dev);
        if (ret)
                return ret;

        /* Disable the adapter */
        __i2c_dw_disable(dev);

        /* Write standard speed timing parameters */
        dw_writel(dev, dev->ss_hcnt, DW_IC_SS_SCL_HCNT);
        dw_writel(dev, dev->ss_lcnt, DW_IC_SS_SCL_LCNT);

        /* Write fast mode/fast mode plus timing parameters */
        dw_writel(dev, dev->fs_hcnt, DW_IC_FS_SCL_HCNT);
        dw_writel(dev, dev->fs_lcnt, DW_IC_FS_SCL_LCNT);

        /* Write high speed timing parameters if supported */
        if (dev->hs_hcnt && dev->hs_lcnt) {
                dw_writel(dev, dev->hs_hcnt, DW_IC_HS_SCL_HCNT);
                dw_writel(dev, dev->hs_lcnt, DW_IC_HS_SCL_LCNT);
        }

        /* Write SDA hold time if supported */
        if (dev->sda_hold_time)
                dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);

        i2c_dw_configure_fifo_master(dev);
        i2c_dw_release_lock(dev);

        return 0;
}

static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
{
        struct i2c_msg *msgs = dev->msgs;
        u32 ic_con, ic_tar = 0;

        /* Disable the adapter */
        __i2c_dw_disable(dev);

        /* If the slave address is ten bit address, enable 10BITADDR */
        ic_con = dw_readl(dev, DW_IC_CON);
        if (msgs[dev->msg_write_idx].flags & I2C_M_TEN) {
                ic_con |= DW_IC_CON_10BITADDR_MASTER;
                /*
                 * If I2C_DYNAMIC_TAR_UPDATE is set, the 10-bit addressing
                 * mode has to be enabled via bit 12 of IC_TAR register.
                 * We set it always as I2C_DYNAMIC_TAR_UPDATE can't be
                 * detected from registers.
                 */
                ic_tar = DW_IC_TAR_10BITADDR_MASTER;
        } else {
                ic_con &= ~DW_IC_CON_10BITADDR_MASTER;
        }

        dw_writel(dev, ic_con, DW_IC_CON);

        /*
         * Set the slave (target) address and enable 10-bit addressing mode
         * if applicable.
         */
        dw_writel(dev, msgs[dev->msg_write_idx].addr | ic_tar, DW_IC_TAR);

        /* Enforce disabled interrupts (due to HW issues) */
        i2c_dw_disable_int(dev);

        /* Enable the adapter */
        __i2c_dw_enable(dev);

        /* Dummy read to avoid the register getting stuck on Bay Trail */
        dw_readl(dev, DW_IC_ENABLE_STATUS);

        /* Clear and enable interrupts */
        dw_readl(dev, DW_IC_CLR_INTR);
        dw_writel(dev, DW_IC_INTR_MASTER_MASK, DW_IC_INTR_MASK);
}

/*
 * Initiate (and continue) low level master read/write transaction.
 * This function is only called from i2c_dw_isr, and pumping i2c_msg
 * messages into the tx buffer.  Even if the size of i2c_msg data is
 * longer than the size of the tx buffer, it handles everything.
 */
static void
i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
{
        struct i2c_msg *msgs = dev->msgs;
        u32 intr_mask;
        int tx_limit, rx_limit;
        u32 addr = msgs[dev->msg_write_idx].addr;
        u32 buf_len = dev->tx_buf_len;
        u8 *buf = dev->tx_buf;
        bool need_restart = false;

        intr_mask = DW_IC_INTR_MASTER_MASK;

        for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) {
                u32 flags = msgs[dev->msg_write_idx].flags;

                /*
                 * If target address has changed, we need to
                 * reprogram the target address in the I2C
                 * adapter when we are done with this transfer.
                 */
                if (msgs[dev->msg_write_idx].addr != addr) {
                        dev_err(dev->dev,
                                "%s: invalid target address\n", __func__);
                        dev->msg_err = -EINVAL;
                        break;
                }

                if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
                        /* new i2c_msg */
                        buf = msgs[dev->msg_write_idx].buf;
                        buf_len = msgs[dev->msg_write_idx].len;

                        /* If both IC_EMPTYFIFO_HOLD_MASTER_EN and
                         * IC_RESTART_EN are set, we must manually
                         * set restart bit between messages.
                         */
                        if ((dev->master_cfg & DW_IC_CON_RESTART_EN) &&
                                        (dev->msg_write_idx > 0))
                                need_restart = true;
                }

                tx_limit = dev->tx_fifo_depth - dw_readl(dev, DW_IC_TXFLR);
                rx_limit = dev->rx_fifo_depth - dw_readl(dev, DW_IC_RXFLR);

                while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
                        u32 cmd = 0;

                        /*
                         * If IC_EMPTYFIFO_HOLD_MASTER_EN is set we must
                         * manually set the stop bit. However, it cannot be
                         * detected from the registers so we set it always
                         * when writing/reading the last byte.
                         */

                        /*
                         * i2c-core always sets the buffer length of
                         * I2C_FUNC_SMBUS_BLOCK_DATA to 1. The length will
                         * be adjusted when receiving the first byte.
                         * Thus we can't stop the transaction here.
                         */
                        if (dev->msg_write_idx == dev->msgs_num - 1 &&
                            buf_len == 1 && !(flags & I2C_M_RECV_LEN))
                                cmd |= BIT(9);

                        if (need_restart) {
                                cmd |= BIT(10);
                                need_restart = false;
                        }

                        if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {

                                /* Avoid rx buffer overrun */
                                if (dev->rx_outstanding >= dev->rx_fifo_depth)
                                        break;

                                dw_writel(dev, cmd | 0x100, DW_IC_DATA_CMD);
                                rx_limit--;
                                dev->rx_outstanding++;
                        } else
                                dw_writel(dev, cmd | *buf++, DW_IC_DATA_CMD);
                        tx_limit--; buf_len--;
                }

                dev->tx_buf = buf;
                dev->tx_buf_len = buf_len;

                /*
                 * Because we don't know the buffer length in the
                 * I2C_FUNC_SMBUS_BLOCK_DATA case, we can't stop
                 * the transaction here.
                 */
                if (buf_len > 0 || flags & I2C_M_RECV_LEN) {
                        /* more bytes to be written */
                        dev->status |= STATUS_WRITE_IN_PROGRESS;
                        break;
                } else
                        dev->status &= ~STATUS_WRITE_IN_PROGRESS;
        }

        /*
         * If i2c_msg index search is completed, we don't need TX_EMPTY
         * interrupt any more.
         */
        if (dev->msg_write_idx == dev->msgs_num)
                intr_mask &= ~DW_IC_INTR_TX_EMPTY;

        if (dev->msg_err)
                intr_mask = 0;

        dw_writel(dev, intr_mask,  DW_IC_INTR_MASK);
}

static u8
i2c_dw_recv_len(struct dw_i2c_dev *dev, u8 len)
{
        struct i2c_msg *msgs = dev->msgs;
        u32 flags = msgs[dev->msg_read_idx].flags;

        /*
         * Adjust the buffer length and mask the flag
         * after receiving the first byte.
         */
        len += (flags & I2C_CLIENT_PEC) ? 2 : 1;
        dev->tx_buf_len = len - min_t(u8, len, dev->rx_outstanding);
        msgs[dev->msg_read_idx].len = len;
        msgs[dev->msg_read_idx].flags &= ~I2C_M_RECV_LEN;

        return len;
}

static void
i2c_dw_read(struct dw_i2c_dev *dev)
{
        struct i2c_msg *msgs = dev->msgs;
        int rx_valid;

        for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) {
                u32 len;
                u8 *buf;

                if (!(msgs[dev->msg_read_idx].flags & I2C_M_RD))
                        continue;

                if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
                        len = msgs[dev->msg_read_idx].len;
                        buf = msgs[dev->msg_read_idx].buf;
                } else {
                        len = dev->rx_buf_len;
                        buf = dev->rx_buf;
                }

                rx_valid = dw_readl(dev, DW_IC_RXFLR);

                for (; len > 0 && rx_valid > 0; len--, rx_valid--) {
                        u32 flags = msgs[dev->msg_read_idx].flags;

                        *buf = dw_readl(dev, DW_IC_DATA_CMD);
                        /* Ensure length byte is a valid value */
                        if (flags & I2C_M_RECV_LEN &&
                                *buf <= I2C_SMBUS_BLOCK_MAX && *buf > 0) {
                                len = i2c_dw_recv_len(dev, *buf);
                        }
                        buf++;
                        dev->rx_outstanding--;
                }

                if (len > 0) {
                        dev->status |= STATUS_READ_IN_PROGRESS;
                        dev->rx_buf_len = len;
                        dev->rx_buf = buf;
                        return;
                } else
                        dev->status &= ~STATUS_READ_IN_PROGRESS;
        }
}

/*
 * Prepare controller for a transaction and call i2c_dw_xfer_msg.
 */
static int
i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
        struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
        int ret;

        dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);

        pm_runtime_get_sync(dev->dev);

        reinit_completion(&dev->cmd_complete);
        dev->msgs = msgs;
        dev->msgs_num = num;
        dev->cmd_err = 0;
        dev->msg_write_idx = 0;
        dev->msg_read_idx = 0;
        dev->msg_err = 0;
        dev->status = STATUS_IDLE;
        dev->abort_source = 0;
        dev->rx_outstanding = 0;

        ret = i2c_dw_acquire_lock(dev);
        if (ret)
                goto done_nolock;

        ret = i2c_dw_wait_bus_not_busy(dev);
        if (ret < 0)
                goto done;

        /* Start the transfers */
        i2c_dw_xfer_init(dev);

        /* Wait for tx to complete */
        if (!wait_for_completion_timeout(&dev->cmd_complete, adap->timeout)) {
                dev_err(dev->dev, "controller timed out\n");
                /* i2c_dw_init implicitly disables the adapter */
                i2c_recover_bus(&dev->adapter);
                i2c_dw_init_master(dev);
                ret = -ETIMEDOUT;
                goto done;
        }

        /*
         * We must disable the adapter before returning and signaling the end
         * of the current transfer. Otherwise the hardware might continue
         * generating interrupts which in turn causes a race condition with
         * the following transfer.  Needs some more investigation if the
         * additional interrupts are a hardware bug or this driver doesn't
         * handle them correctly yet.
         */
        __i2c_dw_disable_nowait(dev);

        if (dev->msg_err) {
                ret = dev->msg_err;
                goto done;
        }

        /* No error */
        if (likely(!dev->cmd_err && !dev->status)) {
                ret = num;
                goto done;
        }

        /* We have an error */
        if (dev->cmd_err == DW_IC_ERR_TX_ABRT) {
                ret = i2c_dw_handle_tx_abort(dev);
                goto done;
        }

        if (dev->status)
                dev_err(dev->dev,
                        "transfer terminated early - interrupt latency too high?\n");

        ret = -EIO;

done:
        i2c_dw_release_lock(dev);

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

        return ret;
}

static const struct i2c_algorithm i2c_dw_algo = {
        .master_xfer = i2c_dw_xfer,
        .functionality = i2c_dw_func,
};

static const struct i2c_adapter_quirks i2c_dw_quirks = {
        .flags = I2C_AQ_NO_ZERO_LEN,
};

static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
{
        u32 stat;

        /*
         * The IC_INTR_STAT register just indicates "enabled" interrupts.
         * Ths unmasked raw version of interrupt status bits are available
         * in the IC_RAW_INTR_STAT register.
         *
         * That is,
         *   stat = dw_readl(IC_INTR_STAT);
         * equals to,
         *   stat = dw_readl(IC_RAW_INTR_STAT) & dw_readl(IC_INTR_MASK);
         *
         * The raw version might be useful for debugging purposes.
         */
        stat = dw_readl(dev, DW_IC_INTR_STAT);

        /*
         * Do not use the IC_CLR_INTR register to clear interrupts, or
         * you'll miss some interrupts, triggered during the period from
         * dw_readl(IC_INTR_STAT) to dw_readl(IC_CLR_INTR).
         *
         * Instead, use the separately-prepared IC_CLR_* registers.
         */
        if (stat & DW_IC_INTR_RX_UNDER)
                dw_readl(dev, DW_IC_CLR_RX_UNDER);
        if (stat & DW_IC_INTR_RX_OVER)
                dw_readl(dev, DW_IC_CLR_RX_OVER);
        if (stat & DW_IC_INTR_TX_OVER)
                dw_readl(dev, DW_IC_CLR_TX_OVER);
        if (stat & DW_IC_INTR_RD_REQ)
                dw_readl(dev, DW_IC_CLR_RD_REQ);
        if (stat & DW_IC_INTR_TX_ABRT) {
                /*
                 * The IC_TX_ABRT_SOURCE register is cleared whenever
                 * the IC_CLR_TX_ABRT is read.  Preserve it beforehand.
                 */
                dev->abort_source = dw_readl(dev, DW_IC_TX_ABRT_SOURCE);
                dw_readl(dev, DW_IC_CLR_TX_ABRT);
        }
        if (stat & DW_IC_INTR_RX_DONE)
                dw_readl(dev, DW_IC_CLR_RX_DONE);
        if (stat & DW_IC_INTR_ACTIVITY)
                dw_readl(dev, DW_IC_CLR_ACTIVITY);
        if (stat & DW_IC_INTR_STOP_DET)
                dw_readl(dev, DW_IC_CLR_STOP_DET);
        if (stat & DW_IC_INTR_START_DET)
                dw_readl(dev, DW_IC_CLR_START_DET);
        if (stat & DW_IC_INTR_GEN_CALL)
                dw_readl(dev, DW_IC_CLR_GEN_CALL);

        return stat;
}

/*
 * Interrupt service routine. This gets called whenever an I2C master interrupt
 * occurs.
 */
static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev)
{
        u32 stat;

        stat = i2c_dw_read_clear_intrbits(dev);
        if (stat & DW_IC_INTR_TX_ABRT) {
                dev->cmd_err |= DW_IC_ERR_TX_ABRT;
                dev->status = STATUS_IDLE;

                /*
                 * Anytime TX_ABRT is set, the contents of the tx/rx
                 * buffers are flushed. Make sure to skip them.
                 */
                dw_writel(dev, 0, DW_IC_INTR_MASK);
                goto tx_aborted;
        }

        if (stat & DW_IC_INTR_RX_FULL)
                i2c_dw_read(dev);

        if (stat & DW_IC_INTR_TX_EMPTY)
                i2c_dw_xfer_msg(dev);

        /*
         * No need to modify or disable the interrupt mask here.
         * i2c_dw_xfer_msg() will take care of it according to
         * the current transmit status.
         */

tx_aborted:
        if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
                complete(&dev->cmd_complete);
        else if (unlikely(dev->flags & ACCESS_INTR_MASK)) {
                /* Workaround to trigger pending interrupt */
                stat = dw_readl(dev, DW_IC_INTR_MASK);
                i2c_dw_disable_int(dev);
                dw_writel(dev, stat, DW_IC_INTR_MASK);
        }

        return 0;
}

static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
{
        struct dw_i2c_dev *dev = dev_id;
        u32 stat, enabled;

        enabled = dw_readl(dev, DW_IC_ENABLE);
        stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
        dev_dbg(dev->dev, "enabled=%#x stat=%#x\n", enabled, stat);
        if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
                return IRQ_NONE;

        i2c_dw_irq_handler_master(dev);

        return IRQ_HANDLED;
}

static void i2c_dw_prepare_recovery(struct i2c_adapter *adap)
{
        struct dw_i2c_dev *dev = i2c_get_adapdata(adap);

        i2c_dw_disable(dev);
        reset_control_assert(dev->rst);
        i2c_dw_prepare_clk(dev, false);
}

static void i2c_dw_unprepare_recovery(struct i2c_adapter *adap)
{
        struct dw_i2c_dev *dev = i2c_get_adapdata(adap);

        i2c_dw_prepare_clk(dev, true);
        reset_control_deassert(dev->rst);
        i2c_dw_init_master(dev);
}

static int i2c_dw_init_recovery_info(struct dw_i2c_dev *dev)
{
        struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
        struct i2c_adapter *adap = &dev->adapter;
        struct gpio_desc *gpio;
        int r;

        gpio = devm_gpiod_get(dev->dev, "scl", GPIOD_OUT_HIGH);
        if (IS_ERR(gpio)) {
                r = PTR_ERR(gpio);
                if (r == -ENOENT || r == -ENOSYS)
                        return 0;
                return r;
        }
        rinfo->scl_gpiod = gpio;

        gpio = devm_gpiod_get_optional(dev->dev, "sda", GPIOD_IN);
        if (IS_ERR(gpio))
                return PTR_ERR(gpio);
        rinfo->sda_gpiod = gpio;

        rinfo->recover_bus = i2c_generic_scl_recovery;
        rinfo->prepare_recovery = i2c_dw_prepare_recovery;
        rinfo->unprepare_recovery = i2c_dw_unprepare_recovery;
        adap->bus_recovery_info = rinfo;

        dev_info(dev->dev, "running with gpio recovery mode! scl%s",
                 rinfo->sda_gpiod ? ",sda" : "");

        return 0;
}

int i2c_dw_probe(struct dw_i2c_dev *dev)
{
        struct i2c_adapter *adap = &dev->adapter;
        unsigned long irq_flags;
        int ret;

        init_completion(&dev->cmd_complete);

        dev->init = i2c_dw_init_master;
        dev->disable = i2c_dw_disable;
        dev->disable_int = i2c_dw_disable_int;

        ret = i2c_dw_set_reg_access(dev);
        if (ret)
                return ret;

        ret = i2c_dw_set_timings_master(dev);
        if (ret)
                return ret;

        ret = dev->init(dev);
        if (ret)
                return ret;

        snprintf(adap->name, sizeof(adap->name),
                 "Synopsys DesignWare I2C adapter");
        adap->retries = 3;
        adap->algo = &i2c_dw_algo;
        adap->quirks = &i2c_dw_quirks;
        adap->dev.parent = dev->dev;
        i2c_set_adapdata(adap, dev);

        if (dev->pm_disabled) {
                irq_flags = IRQF_NO_SUSPEND;
        } else {
                irq_flags = IRQF_SHARED | IRQF_COND_SUSPEND;
        }

        i2c_dw_disable_int(dev);
        ret = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr, irq_flags,
                               dev_name(dev->dev), dev);
        if (ret) {
                dev_err(dev->dev, "failure requesting irq %i: %d\n",
                        dev->irq, ret);
                return ret;
        }

        ret = i2c_dw_init_recovery_info(dev);
        if (ret)
                return ret;

        /*
         * Increment PM usage count during adapter registration in order to
         * avoid possible spurious runtime suspend when adapter device is
         * registered to the device core and immediate resume in case bus has
         * registered I2C slaves that do I2C transfers in their probe.
         */
        pm_runtime_get_noresume(dev->dev);
        ret = i2c_add_numbered_adapter(adap);
        if (ret)
                dev_err(dev->dev, "failure adding adapter: %d\n", ret);
        pm_runtime_put_noidle(dev->dev);

        return ret;
}
EXPORT_SYMBOL_GPL(i2c_dw_probe);

MODULE_DESCRIPTION("Synopsys DesignWare I2C bus master adapter");
MODULE_LICENSE("GPL");