/*
 * Copyright (c) 2009-2013, The Linux Foundation. All rights reserved.
 * Copyright (c) 2014, Sony Mobile Communications AB.
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * 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.
 *
 */

#include <linux/acpi.h>
#include <linux/atomic.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/scatterlist.h>

/* QUP Registers */
#define QUP_CONFIG              0x000
#define QUP_STATE               0x004
#define QUP_IO_MODE             0x008
#define QUP_SW_RESET            0x00c
#define QUP_OPERATIONAL         0x018
#define QUP_ERROR_FLAGS         0x01c
#define QUP_ERROR_FLAGS_EN      0x020
#define QUP_OPERATIONAL_MASK    0x028
#define QUP_HW_VERSION          0x030
#define QUP_MX_OUTPUT_CNT       0x100
#define QUP_OUT_FIFO_BASE       0x110
#define QUP_MX_WRITE_CNT        0x150
#define QUP_MX_INPUT_CNT        0x200
#define QUP_MX_READ_CNT         0x208
#define QUP_IN_FIFO_BASE        0x218
#define QUP_I2C_CLK_CTL         0x400
#define QUP_I2C_STATUS          0x404
#define QUP_I2C_MASTER_GEN      0x408

/* QUP States and reset values */
#define QUP_RESET_STATE         0
#define QUP_RUN_STATE           1
#define QUP_PAUSE_STATE         3
#define QUP_STATE_MASK          3

#define QUP_STATE_VALID         BIT(2)
#define QUP_I2C_MAST_GEN        BIT(4)
#define QUP_I2C_FLUSH           BIT(6)

#define QUP_OPERATIONAL_RESET   0x000ff0
#define QUP_I2C_STATUS_RESET    0xfffffc

/* QUP OPERATIONAL FLAGS */
#define QUP_I2C_NACK_FLAG       BIT(3)
#define QUP_OUT_NOT_EMPTY       BIT(4)
#define QUP_IN_NOT_EMPTY        BIT(5)
#define QUP_OUT_FULL            BIT(6)
#define QUP_OUT_SVC_FLAG        BIT(8)
#define QUP_IN_SVC_FLAG         BIT(9)
#define QUP_MX_OUTPUT_DONE      BIT(10)
#define QUP_MX_INPUT_DONE       BIT(11)

/* I2C mini core related values */
#define QUP_CLOCK_AUTO_GATE     BIT(13)
#define I2C_MINI_CORE           (2 << 8)
#define I2C_N_VAL               15
#define I2C_N_VAL_V2            7

/* Most significant word offset in FIFO port */
#define QUP_MSW_SHIFT           (I2C_N_VAL + 1)

/* Packing/Unpacking words in FIFOs, and IO modes */
#define QUP_OUTPUT_BLK_MODE     (1 << 10)
#define QUP_OUTPUT_BAM_MODE     (3 << 10)
#define QUP_INPUT_BLK_MODE      (1 << 12)
#define QUP_INPUT_BAM_MODE      (3 << 12)
#define QUP_BAM_MODE            (QUP_OUTPUT_BAM_MODE | QUP_INPUT_BAM_MODE)
#define QUP_UNPACK_EN           BIT(14)
#define QUP_PACK_EN             BIT(15)

#define QUP_REPACK_EN           (QUP_UNPACK_EN | QUP_PACK_EN)
#define QUP_V2_TAGS_EN          1

#define QUP_OUTPUT_BLOCK_SIZE(x)(((x) >> 0) & 0x03)
#define QUP_OUTPUT_FIFO_SIZE(x) (((x) >> 2) & 0x07)
#define QUP_INPUT_BLOCK_SIZE(x) (((x) >> 5) & 0x03)
#define QUP_INPUT_FIFO_SIZE(x)  (((x) >> 7) & 0x07)

/* QUP tags */
#define QUP_TAG_START           (1 << 8)
#define QUP_TAG_DATA            (2 << 8)
#define QUP_TAG_STOP            (3 << 8)
#define QUP_TAG_REC             (4 << 8)
#define QUP_BAM_INPUT_EOT               0x93
#define QUP_BAM_FLUSH_STOP              0x96

/* QUP v2 tags */
#define QUP_TAG_V2_START               0x81
#define QUP_TAG_V2_DATAWR              0x82
#define QUP_TAG_V2_DATAWR_STOP         0x83
#define QUP_TAG_V2_DATARD              0x85
#define QUP_TAG_V2_DATARD_STOP         0x87

/* Status, Error flags */
#define I2C_STATUS_WR_BUFFER_FULL       BIT(0)
#define I2C_STATUS_BUS_ACTIVE           BIT(8)
#define I2C_STATUS_ERROR_MASK           0x38000fc
#define QUP_STATUS_ERROR_FLAGS          0x7c

#define QUP_READ_LIMIT                  256
#define SET_BIT                         0x1
#define RESET_BIT                       0x0
#define ONE_BYTE                        0x1
#define QUP_I2C_MX_CONFIG_DURING_RUN   BIT(31)

#define MX_TX_RX_LEN                    SZ_64K
#define MX_BLOCKS                       (MX_TX_RX_LEN / QUP_READ_LIMIT)

/* Max timeout in ms for 32k bytes */
#define TOUT_MAX                        300

/* Default values. Use these if FW query fails */
#define DEFAULT_CLK_FREQ 100000
#define DEFAULT_SRC_CLK 20000000

struct qup_i2c_block {
        int     count;
        int     pos;
        int     tx_tag_len;
        int     rx_tag_len;
        int     data_len;
        u8      tags[6];
};

struct qup_i2c_tag {
        u8 *start;
        dma_addr_t addr;
};

struct qup_i2c_bam {
        struct  qup_i2c_tag tag;
        struct  dma_chan *dma;
        struct  scatterlist *sg;
};

struct qup_i2c_dev {
        struct device           *dev;
        void __iomem            *base;
        int                     irq;
        struct clk              *clk;
        struct clk              *pclk;
        struct i2c_adapter      adap;

        int                     clk_ctl;
        int                     out_fifo_sz;
        int                     in_fifo_sz;
        int                     out_blk_sz;
        int                     in_blk_sz;

        unsigned long           one_byte_t;
        struct qup_i2c_block    blk;

        struct i2c_msg          *msg;
        /* Current posion in user message buffer */
        int                     pos;
        /* I2C protocol errors */
        u32                     bus_err;
        /* QUP core errors */
        u32                     qup_err;

        /* To check if this is the last msg */
        bool                    is_last;

        /* To configure when bus is in run state */
        int                     config_run;

        /* dma parameters */
        bool                    is_dma;
        struct                  dma_pool *dpool;
        struct                  qup_i2c_tag start_tag;
        struct                  qup_i2c_bam brx;
        struct                  qup_i2c_bam btx;

        struct completion       xfer;
};

static irqreturn_t qup_i2c_interrupt(int irq, void *dev)
{
        struct qup_i2c_dev *qup = dev;
        u32 bus_err;
        u32 qup_err;
        u32 opflags;

        bus_err = readl(qup->base + QUP_I2C_STATUS);
        qup_err = readl(qup->base + QUP_ERROR_FLAGS);
        opflags = readl(qup->base + QUP_OPERATIONAL);

        if (!qup->msg) {
                /* Clear Error interrupt */
                writel(QUP_RESET_STATE, qup->base + QUP_STATE);
                return IRQ_HANDLED;
        }

        bus_err &= I2C_STATUS_ERROR_MASK;
        qup_err &= QUP_STATUS_ERROR_FLAGS;

        /* Clear the error bits in QUP_ERROR_FLAGS */
        if (qup_err)
                writel(qup_err, qup->base + QUP_ERROR_FLAGS);

        /* Clear the error bits in QUP_I2C_STATUS */
        if (bus_err)
                writel(bus_err, qup->base + QUP_I2C_STATUS);

        /* Reset the QUP State in case of error */
        if (qup_err || bus_err) {
                writel(QUP_RESET_STATE, qup->base + QUP_STATE);
                goto done;
        }

        if (opflags & QUP_IN_SVC_FLAG)
                writel(QUP_IN_SVC_FLAG, qup->base + QUP_OPERATIONAL);

        if (opflags & QUP_OUT_SVC_FLAG)
                writel(QUP_OUT_SVC_FLAG, qup->base + QUP_OPERATIONAL);

done:
        qup->qup_err = qup_err;
        qup->bus_err = bus_err;
        complete(&qup->xfer);
        return IRQ_HANDLED;
}

static int qup_i2c_poll_state_mask(struct qup_i2c_dev *qup,
                                   u32 req_state, u32 req_mask)
{
        int retries = 1;
        u32 state;

        /*
         * State transition takes 3 AHB clocks cycles + 3 I2C master clock
         * cycles. So retry once after a 1uS delay.
         */
        do {
                state = readl(qup->base + QUP_STATE);

                if (state & QUP_STATE_VALID &&
                    (state & req_mask) == req_state)
                        return 0;

                udelay(1);
        } while (retries--);

        return -ETIMEDOUT;
}

static int qup_i2c_poll_state(struct qup_i2c_dev *qup, u32 req_state)
{
        return qup_i2c_poll_state_mask(qup, req_state, QUP_STATE_MASK);
}

static void qup_i2c_flush(struct qup_i2c_dev *qup)
{
        u32 val = readl(qup->base + QUP_STATE);

        val |= QUP_I2C_FLUSH;
        writel(val, qup->base + QUP_STATE);
}

static int qup_i2c_poll_state_valid(struct qup_i2c_dev *qup)
{
        return qup_i2c_poll_state_mask(qup, 0, 0);
}

static int qup_i2c_poll_state_i2c_master(struct qup_i2c_dev *qup)
{
        return qup_i2c_poll_state_mask(qup, QUP_I2C_MAST_GEN, QUP_I2C_MAST_GEN);
}

static int qup_i2c_change_state(struct qup_i2c_dev *qup, u32 state)
{
        if (qup_i2c_poll_state_valid(qup) != 0)
                return -EIO;

        writel(state, qup->base + QUP_STATE);

        if (qup_i2c_poll_state(qup, state) != 0)
                return -EIO;
        return 0;
}

/**
 * qup_i2c_wait_ready - wait for a give number of bytes in tx/rx path
 * @qup: The qup_i2c_dev device
 * @op: The bit/event to wait on
 * @val: value of the bit to wait on, 0 or 1
 * @len: The length the bytes to be transferred
 */
static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,
                              int len)
{
        unsigned long timeout;
        u32 opflags;
        u32 status;
        u32 shift = __ffs(op);
        int ret = 0;

        len *= qup->one_byte_t;
        /* timeout after a wait of twice the max time */
        timeout = jiffies + len * 4;

        for (;;) {
                opflags = readl(qup->base + QUP_OPERATIONAL);
                status = readl(qup->base + QUP_I2C_STATUS);

                if (((opflags & op) >> shift) == val) {
                        if ((op == QUP_OUT_NOT_EMPTY) && qup->is_last) {
                                if (!(status & I2C_STATUS_BUS_ACTIVE)) {
                                        ret = 0;
                                        goto done;
                                }
                        } else {
                                ret = 0;
                                goto done;
                        }
                }

                if (time_after(jiffies, timeout)) {
                        ret = -ETIMEDOUT;
                        goto done;
                }
                usleep_range(len, len * 2);
        }

done:
        if (qup->bus_err || qup->qup_err)
                ret =  (qup->bus_err & QUP_I2C_NACK_FLAG) ? -ENXIO : -EIO;

        return ret;
}

static void qup_i2c_set_write_mode_v2(struct qup_i2c_dev *qup,
                                      struct i2c_msg *msg)
{
        /* Number of entries to shift out, including the tags */
        int total = msg->len + qup->blk.tx_tag_len;

        total |= qup->config_run;

        if (total < qup->out_fifo_sz) {
                /* FIFO mode */
                writel(QUP_REPACK_EN, qup->base + QUP_IO_MODE);
                writel(total, qup->base + QUP_MX_WRITE_CNT);
        } else {
                /* BLOCK mode (transfer data on chunks) */
                writel(QUP_OUTPUT_BLK_MODE | QUP_REPACK_EN,
                       qup->base + QUP_IO_MODE);
                writel(total, qup->base + QUP_MX_OUTPUT_CNT);
        }
}

static void qup_i2c_set_write_mode(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
        /* Number of entries to shift out, including the start */
        int total = msg->len + 1;

        if (total < qup->out_fifo_sz) {
                /* FIFO mode */
                writel(QUP_REPACK_EN, qup->base + QUP_IO_MODE);
                writel(total, qup->base + QUP_MX_WRITE_CNT);
        } else {
                /* BLOCK mode (transfer data on chunks) */
                writel(QUP_OUTPUT_BLK_MODE | QUP_REPACK_EN,
                       qup->base + QUP_IO_MODE);
                writel(total, qup->base + QUP_MX_OUTPUT_CNT);
        }
}

static int check_for_fifo_space(struct qup_i2c_dev *qup)
{
        int ret;

        ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
        if (ret)
                goto out;

        ret = qup_i2c_wait_ready(qup, QUP_OUT_FULL,
                                 RESET_BIT, 4 * ONE_BYTE);
        if (ret) {
                /* Fifo is full. Drain out the fifo */
                ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
                if (ret)
                        goto out;

                ret = qup_i2c_wait_ready(qup, QUP_OUT_NOT_EMPTY,
                                         RESET_BIT, 256 * ONE_BYTE);
                if (ret) {
                        dev_err(qup->dev, "timeout for fifo out full");
                        goto out;
                }

                ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
                if (ret)
                        goto out;
        }

out:
        return ret;
}

static int qup_i2c_issue_write(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
        u32 addr = msg->addr << 1;
        u32 qup_tag;
        int idx;
        u32 val;
        int ret = 0;

        if (qup->pos == 0) {
                val = QUP_TAG_START | addr;
                idx = 1;
        } else {
                val = 0;
                idx = 0;
        }

        while (qup->pos < msg->len) {
                /* Check that there's space in the FIFO for our pair */
                ret = check_for_fifo_space(qup);
                if (ret)
                        return ret;

                if (qup->pos == msg->len - 1)
                        qup_tag = QUP_TAG_STOP;
                else
                        qup_tag = QUP_TAG_DATA;

                if (idx & 1)
                        val |= (qup_tag | msg->buf[qup->pos]) << QUP_MSW_SHIFT;
                else
                        val = qup_tag | msg->buf[qup->pos];

                /* Write out the pair and the last odd value */
                if (idx & 1 || qup->pos == msg->len - 1)
                        writel(val, qup->base + QUP_OUT_FIFO_BASE);

                qup->pos++;
                idx++;
        }

        ret = qup_i2c_change_state(qup, QUP_RUN_STATE);

        return ret;
}

static void qup_i2c_set_blk_data(struct qup_i2c_dev *qup,
                                 struct i2c_msg *msg)
{
        memset(&qup->blk, 0, sizeof(qup->blk));

        qup->blk.data_len = msg->len;
        qup->blk.count = (msg->len + QUP_READ_LIMIT - 1) / QUP_READ_LIMIT;

        /* 4 bytes for first block and 2 writes for rest */
        qup->blk.tx_tag_len = 4 + (qup->blk.count - 1) * 2;

        /* There are 2 tag bytes that are read in to fifo for every block */
        if (msg->flags & I2C_M_RD)
                qup->blk.rx_tag_len = qup->blk.count * 2;
}

static int qup_i2c_send_data(struct qup_i2c_dev *qup, int tlen, u8 *tbuf,
                             int dlen, u8 *dbuf)
{
        u32 val = 0, idx = 0, pos = 0, i = 0, t;
        int  len = tlen + dlen;
        u8 *buf = tbuf;
        int ret = 0;

        while (len > 0) {
                ret = check_for_fifo_space(qup);
                if (ret)
                        return ret;

                t = (len >= 4) ? 4 : len;

                while (idx < t) {
                        if (!i && (pos >= tlen)) {
                                buf = dbuf;
                                pos = 0;
                                i = 1;
                        }
                        val |= buf[pos++] << (idx++ * 8);
                }

                writel(val, qup->base + QUP_OUT_FIFO_BASE);
                idx  = 0;
                val = 0;
                len -= 4;
        }

        ret = qup_i2c_change_state(qup, QUP_RUN_STATE);

        return ret;
}

static int qup_i2c_get_data_len(struct qup_i2c_dev *qup)
{
        int data_len;

        if (qup->blk.data_len > QUP_READ_LIMIT)
                data_len = QUP_READ_LIMIT;
        else
                data_len = qup->blk.data_len;

        return data_len;
}

static bool qup_i2c_check_msg_len(struct i2c_msg *msg)
{
        return ((msg->flags & I2C_M_RD) && (msg->flags & I2C_M_RECV_LEN));
}

static int qup_i2c_set_tags_smb(u16 addr, u8 *tags, struct qup_i2c_dev *qup,
                        struct i2c_msg *msg)
{
        int len = 0;

        if (msg->len > 1) {
                tags[len++] = QUP_TAG_V2_DATARD_STOP;
                tags[len++] = qup_i2c_get_data_len(qup) - 1;
        } else {
                tags[len++] = QUP_TAG_V2_START;
                tags[len++] = addr & 0xff;

                if (msg->flags & I2C_M_TEN)
                        tags[len++] = addr >> 8;

                tags[len++] = QUP_TAG_V2_DATARD;
                /* Read 1 byte indicating the length of the SMBus message */
                tags[len++] = 1;
        }
        return len;
}

static int qup_i2c_set_tags(u8 *tags, struct qup_i2c_dev *qup,
                            struct i2c_msg *msg,  int is_dma)
{
        u16 addr = i2c_8bit_addr_from_msg(msg);
        int len = 0;
        int data_len;

        int last = (qup->blk.pos == (qup->blk.count - 1)) && (qup->is_last);

        /* Handle tags for SMBus block read */
        if (qup_i2c_check_msg_len(msg))
                return qup_i2c_set_tags_smb(addr, tags, qup, msg);

        if (qup->blk.pos == 0) {
                tags[len++] = QUP_TAG_V2_START;
                tags[len++] = addr & 0xff;

                if (msg->flags & I2C_M_TEN)
                        tags[len++] = addr >> 8;
        }

        /* Send _STOP commands for the last block */
        if (last) {
                if (msg->flags & I2C_M_RD)
                        tags[len++] = QUP_TAG_V2_DATARD_STOP;
                else
                        tags[len++] = QUP_TAG_V2_DATAWR_STOP;
        } else {
                if (msg->flags & I2C_M_RD)
                        tags[len++] = QUP_TAG_V2_DATARD;
                else
                        tags[len++] = QUP_TAG_V2_DATAWR;
        }

        data_len = qup_i2c_get_data_len(qup);

        /* 0 implies 256 bytes */
        if (data_len == QUP_READ_LIMIT)
                tags[len++] = 0;
        else
                tags[len++] = data_len;

        if ((msg->flags & I2C_M_RD) && last && is_dma) {
                tags[len++] = QUP_BAM_INPUT_EOT;
                tags[len++] = QUP_BAM_FLUSH_STOP;
        }

        return len;
}

static int qup_i2c_issue_xfer_v2(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
        int data_len = 0, tag_len, index;
        int ret;

        tag_len = qup_i2c_set_tags(qup->blk.tags, qup, msg, 0);
        index = msg->len - qup->blk.data_len;

        /* only tags are written for read */
        if (!(msg->flags & I2C_M_RD))
                data_len = qup_i2c_get_data_len(qup);

        ret = qup_i2c_send_data(qup, tag_len, qup->blk.tags,
                                data_len, &msg->buf[index]);
        qup->blk.data_len -= data_len;

        return ret;
}

static void qup_i2c_bam_cb(void *data)
{
        struct qup_i2c_dev *qup = data;

        complete(&qup->xfer);
}

static int qup_sg_set_buf(struct scatterlist *sg, void *buf,
                          unsigned int buflen, struct qup_i2c_dev *qup,
                          int dir)
{
        int ret;

        sg_set_buf(sg, buf, buflen);
        ret = dma_map_sg(qup->dev, sg, 1, dir);
        if (!ret)
                return -EINVAL;

        return 0;
}

static void qup_i2c_rel_dma(struct qup_i2c_dev *qup)
{
        if (qup->btx.dma)
                dma_release_channel(qup->btx.dma);
        if (qup->brx.dma)
                dma_release_channel(qup->brx.dma);
        qup->btx.dma = NULL;
        qup->brx.dma = NULL;
}

static int qup_i2c_req_dma(struct qup_i2c_dev *qup)
{
        int err;

        if (!qup->btx.dma) {
                qup->btx.dma = dma_request_slave_channel_reason(qup->dev, "tx");
                if (IS_ERR(qup->btx.dma)) {
                        err = PTR_ERR(qup->btx.dma);
                        qup->btx.dma = NULL;
                        dev_err(qup->dev, "\n tx channel not available");
                        return err;
                }
        }

        if (!qup->brx.dma) {
                qup->brx.dma = dma_request_slave_channel_reason(qup->dev, "rx");
                if (IS_ERR(qup->brx.dma)) {
                        dev_err(qup->dev, "\n rx channel not available");
                        err = PTR_ERR(qup->brx.dma);
                        qup->brx.dma = NULL;
                        qup_i2c_rel_dma(qup);
                        return err;
                }
        }
        return 0;
}

static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
                               int num)
{
        struct dma_async_tx_descriptor *txd, *rxd = NULL;
        int ret = 0, idx = 0, limit = QUP_READ_LIMIT;
        dma_cookie_t cookie_rx, cookie_tx;
        u32 rx_nents = 0, tx_nents = 0, len, blocks, rem;
        u32 i, tlen, tx_len, tx_buf = 0, rx_buf = 0, off = 0;
        u8 *tags;

        while (idx < num) {
                tx_len = 0, len = 0, i = 0;

                qup->is_last = (idx == (num - 1));

                qup_i2c_set_blk_data(qup, msg);

                blocks = qup->blk.count;
                rem = msg->len - (blocks - 1) * limit;

                if (msg->flags & I2C_M_RD) {
                        rx_nents += (blocks * 2) + 1;
                        tx_nents += 1;

                        while (qup->blk.pos < blocks) {
                                tlen = (i == (blocks - 1)) ? rem : limit;
                                tags = &qup->start_tag.start[off + len];
                                len += qup_i2c_set_tags(tags, qup, msg, 1);
                                qup->blk.data_len -= tlen;

                                /* scratch buf to read the start and len tags */
                                ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
                                                     &qup->brx.tag.start[0],
                                                     2, qup, DMA_FROM_DEVICE);

                                if (ret)
                                        return ret;

                                ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
                                                     &msg->buf[limit * i],
                                                     tlen, qup,
                                                     DMA_FROM_DEVICE);
                                if (ret)
                                        return ret;

                                i++;
                                qup->blk.pos = i;
                        }
                        ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
                                             &qup->start_tag.start[off],
                                             len, qup, DMA_TO_DEVICE);
                        if (ret)
                                return ret;

                        off += len;
                        /* scratch buf to read the BAM EOT and FLUSH tags */
                        ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
                                             &qup->brx.tag.start[0],
                                             2, qup, DMA_FROM_DEVICE);
                        if (ret)
                                return ret;
                } else {
                        tx_nents += (blocks * 2);

                        while (qup->blk.pos < blocks) {
                                tlen = (i == (blocks - 1)) ? rem : limit;
                                tags = &qup->start_tag.start[off + tx_len];
                                len = qup_i2c_set_tags(tags, qup, msg, 1);
                                qup->blk.data_len -= tlen;

                                ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
                                                     tags, len,
                                                     qup, DMA_TO_DEVICE);
                                if (ret)
                                        return ret;

                                tx_len += len;
                                ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
                                                     &msg->buf[limit * i],
                                                     tlen, qup, DMA_TO_DEVICE);
                                if (ret)
                                        return ret;
                                i++;
                                qup->blk.pos = i;
                        }
                        off += tx_len;

                        if (idx == (num - 1)) {
                                len = 1;
                                if (rx_nents) {
                                        qup->btx.tag.start[0] =
                                                        QUP_BAM_INPUT_EOT;
                                        len++;
                                }
                                qup->btx.tag.start[len - 1] =
                                                        QUP_BAM_FLUSH_STOP;
                                ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
                                                     &qup->btx.tag.start[0],
                                                     len, qup, DMA_TO_DEVICE);
                                if (ret)
                                        return ret;
                                tx_nents += 1;
                        }
                }
                idx++;
                msg++;
        }

        txd = dmaengine_prep_slave_sg(qup->btx.dma, qup->btx.sg, tx_nents,
                                      DMA_MEM_TO_DEV,
                                      DMA_PREP_INTERRUPT | DMA_PREP_FENCE);
        if (!txd) {
                dev_err(qup->dev, "failed to get tx desc\n");
                ret = -EINVAL;
                goto desc_err;
        }

        if (!rx_nents) {
                txd->callback = qup_i2c_bam_cb;
                txd->callback_param = qup;
        }

        cookie_tx = dmaengine_submit(txd);
        if (dma_submit_error(cookie_tx)) {
                ret = -EINVAL;
                goto desc_err;
        }

        dma_async_issue_pending(qup->btx.dma);

        if (rx_nents) {
                rxd = dmaengine_prep_slave_sg(qup->brx.dma, qup->brx.sg,
                                              rx_nents, DMA_DEV_TO_MEM,
                                              DMA_PREP_INTERRUPT);
                if (!rxd) {
                        dev_err(qup->dev, "failed to get rx desc\n");
                        ret = -EINVAL;

                        /* abort TX descriptors */
                        dmaengine_terminate_all(qup->btx.dma);
                        goto desc_err;
                }

                rxd->callback = qup_i2c_bam_cb;
                rxd->callback_param = qup;
                cookie_rx = dmaengine_submit(rxd);
                if (dma_submit_error(cookie_rx)) {
                        ret = -EINVAL;
                        goto desc_err;
                }

                dma_async_issue_pending(qup->brx.dma);
        }

        if (!wait_for_completion_timeout(&qup->xfer, TOUT_MAX * HZ)) {
                dev_err(qup->dev, "normal trans timed out\n");
                ret = -ETIMEDOUT;
        }

        if (ret || qup->bus_err || qup->qup_err) {
                if (qup_i2c_change_state(qup, QUP_RUN_STATE)) {
                        dev_err(qup->dev, "change to run state timed out");
                        goto desc_err;
                }

                if (rx_nents)
                        writel(QUP_BAM_INPUT_EOT,
                               qup->base + QUP_OUT_FIFO_BASE);

                writel(QUP_BAM_FLUSH_STOP, qup->base + QUP_OUT_FIFO_BASE);

                qup_i2c_flush(qup);

                /* wait for remaining interrupts to occur */
                if (!wait_for_completion_timeout(&qup->xfer, HZ))
                        dev_err(qup->dev, "flush timed out\n");

                qup_i2c_rel_dma(qup);

                ret =  (qup->bus_err & QUP_I2C_NACK_FLAG) ? -ENXIO : -EIO;
        }

desc_err:
        dma_unmap_sg(qup->dev, qup->btx.sg, tx_nents, DMA_TO_DEVICE);

        if (rx_nents)
                dma_unmap_sg(qup->dev, qup->brx.sg, rx_nents,
                             DMA_FROM_DEVICE);

        return ret;
}

static int qup_i2c_bam_xfer(struct i2c_adapter *adap, struct i2c_msg *msg,
                            int num)
{
        struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
        int ret = 0;

        enable_irq(qup->irq);
        ret = qup_i2c_req_dma(qup);

        if (ret)
                goto out;

        writel(0, qup->base + QUP_MX_INPUT_CNT);
        writel(0, qup->base + QUP_MX_OUTPUT_CNT);

        /* set BAM mode */
        writel(QUP_REPACK_EN | QUP_BAM_MODE, qup->base + QUP_IO_MODE);

        /* mask fifo irqs */
        writel((0x3 << 8), qup->base + QUP_OPERATIONAL_MASK);

        /* set RUN STATE */
        ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
        if (ret)
                goto out;

        writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);

        qup->msg = msg;
        ret = qup_i2c_bam_do_xfer(qup, qup->msg, num);
out:
        disable_irq(qup->irq);

        qup->msg = NULL;
        return ret;
}

static int qup_i2c_wait_for_complete(struct qup_i2c_dev *qup,
                                     struct i2c_msg *msg)
{
        unsigned long left;
        int ret = 0;

        left = wait_for_completion_timeout(&qup->xfer, HZ);
        if (!left) {
                writel(1, qup->base + QUP_SW_RESET);
                ret = -ETIMEDOUT;
        }

        if (qup->bus_err || qup->qup_err)
                ret =  (qup->bus_err & QUP_I2C_NACK_FLAG) ? -ENXIO : -EIO;

        return ret;
}

static int qup_i2c_write_one_v2(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
        int ret = 0;

        qup->msg = msg;
        qup->pos = 0;
        enable_irq(qup->irq);
        qup_i2c_set_blk_data(qup, msg);
        qup_i2c_set_write_mode_v2(qup, msg);

        ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
        if (ret)
                goto err;

        writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);

        do {
                ret = qup_i2c_issue_xfer_v2(qup, msg);
                if (ret)
                        goto err;

                ret = qup_i2c_wait_for_complete(qup, msg);
                if (ret)
                        goto err;

                qup->blk.pos++;
        } while (qup->blk.pos < qup->blk.count);

        ret = qup_i2c_wait_ready(qup, QUP_OUT_NOT_EMPTY, RESET_BIT, ONE_BYTE);

err:
        disable_irq(qup->irq);
        qup->msg = NULL;

        return ret;
}

static int qup_i2c_write_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
        int ret;

        qup->msg = msg;
        qup->pos = 0;

        enable_irq(qup->irq);

        qup_i2c_set_write_mode(qup, msg);

        ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
        if (ret)
                goto err;

        writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);

        do {
                ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
                if (ret)
                        goto err;

                ret = qup_i2c_issue_write(qup, msg);
                if (ret)
                        goto err;

                ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
                if (ret)
                        goto err;

                ret = qup_i2c_wait_for_complete(qup, msg);
                if (ret)
                        goto err;
        } while (qup->pos < msg->len);

        /* Wait for the outstanding data in the fifo to drain */
        ret = qup_i2c_wait_ready(qup, QUP_OUT_NOT_EMPTY, RESET_BIT, ONE_BYTE);
err:
        disable_irq(qup->irq);
        qup->msg = NULL;

        return ret;
}

static void qup_i2c_set_read_mode(struct qup_i2c_dev *qup, int len)
{
        if (len < qup->in_fifo_sz) {
                /* FIFO mode */
                writel(QUP_REPACK_EN, qup->base + QUP_IO_MODE);
                writel(len, qup->base + QUP_MX_READ_CNT);
        } else {
                /* BLOCK mode (transfer data on chunks) */
                writel(QUP_INPUT_BLK_MODE | QUP_REPACK_EN,
                       qup->base + QUP_IO_MODE);
                writel(len, qup->base + QUP_MX_INPUT_CNT);
        }
}

static void qup_i2c_set_read_mode_v2(struct qup_i2c_dev *qup, int len)
{
        int tx_len = qup->blk.tx_tag_len;

        len += qup->blk.rx_tag_len;
        len |= qup->config_run;
        tx_len |= qup->config_run;

        if (len < qup->in_fifo_sz) {
                /* FIFO mode */
                writel(QUP_REPACK_EN, qup->base + QUP_IO_MODE);
                writel(tx_len, qup->base + QUP_MX_WRITE_CNT);
                writel(len, qup->base + QUP_MX_READ_CNT);
        } else {
                /* BLOCK mode (transfer data on chunks) */
                writel(QUP_INPUT_BLK_MODE | QUP_REPACK_EN,
                       qup->base + QUP_IO_MODE);
                writel(tx_len, qup->base + QUP_MX_OUTPUT_CNT);
                writel(len, qup->base + QUP_MX_INPUT_CNT);
        }
}

static void qup_i2c_issue_read(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
        u32 addr, len, val;

        addr = i2c_8bit_addr_from_msg(msg);

        /* 0 is used to specify a length 256 (QUP_READ_LIMIT) */
        len = (msg->len == QUP_READ_LIMIT) ? 0 : msg->len;

        val = ((QUP_TAG_REC | len) << QUP_MSW_SHIFT) | QUP_TAG_START | addr;
        writel(val, qup->base + QUP_OUT_FIFO_BASE);
}


static int qup_i2c_read_fifo(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
        u32 val = 0;
        int idx;
        int ret = 0;

        for (idx = 0; qup->pos < msg->len; idx++) {
                if ((idx & 1) == 0) {
                        /* Check that FIFO have data */
                        ret = qup_i2c_wait_ready(qup, QUP_IN_NOT_EMPTY,
                                                 SET_BIT, 4 * ONE_BYTE);
                        if (ret)
                                return ret;

                        /* Reading 2 words at time */
                        val = readl(qup->base + QUP_IN_FIFO_BASE);

                        msg->buf[qup->pos++] = val & 0xFF;
                } else {
                        msg->buf[qup->pos++] = val >> QUP_MSW_SHIFT;
                }
        }

        return ret;
}

static int qup_i2c_read_fifo_v2(struct qup_i2c_dev *qup,
                                struct i2c_msg *msg)
{
        u32 val;
        int idx, pos = 0, ret = 0, total, msg_offset = 0;

        /*
         * If the message length is already read in
         * the first byte of the buffer, account for
         * that by setting the offset
         */
        if (qup_i2c_check_msg_len(msg) && (msg->len > 1))
                msg_offset = 1;
        total = qup_i2c_get_data_len(qup);
        total -= msg_offset;

        /* 2 extra bytes for read tags */
        while (pos < (total + 2)) {
                /* Check that FIFO have data */
                ret = qup_i2c_wait_ready(qup, QUP_IN_NOT_EMPTY,
                                         SET_BIT, 4 * ONE_BYTE);
                if (ret) {
                        dev_err(qup->dev, "timeout for fifo not empty");
                        return ret;
                }
                val = readl(qup->base + QUP_IN_FIFO_BASE);

                for (idx = 0; idx < 4; idx++, val >>= 8, pos++) {
                        /* first 2 bytes are tag bytes */
                        if (pos < 2)
                                continue;

                        if (pos >= (total + 2))
                                goto out;
                        msg->buf[qup->pos + msg_offset] = val & 0xff;
                        qup->pos++;
                }
        }

out:
        qup->blk.data_len -= total;

        return ret;
}

static int qup_i2c_read_one_v2(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
        int ret = 0;

        qup->msg = msg;
        qup->pos  = 0;
        enable_irq(qup->irq);
        qup_i2c_set_blk_data(qup, msg);
        qup_i2c_set_read_mode_v2(qup, msg->len);

        ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
        if (ret)
                goto err;

        writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);

        do {
                ret = qup_i2c_issue_xfer_v2(qup, msg);
                if (ret)
                        goto err;

                ret = qup_i2c_wait_for_complete(qup, msg);
                if (ret)
                        goto err;

                ret = qup_i2c_read_fifo_v2(qup, msg);
                if (ret)
                        goto err;

                qup->blk.pos++;

                /* Handle SMBus block read length */
                if (qup_i2c_check_msg_len(msg) && (msg->len == 1)) {
                        if (msg->buf[0] > I2C_SMBUS_BLOCK_MAX) {
                                ret = -EPROTO;
                                goto err;
                        }
                        msg->len += msg->buf[0];
                        qup->pos = 0;
                        qup_i2c_set_blk_data(qup, msg);
                        /* set tag length for block read */
                        qup->blk.tx_tag_len = 2;
                        qup_i2c_set_read_mode_v2(qup, msg->buf[0]);
                }
        } while (qup->blk.pos < qup->blk.count);

err:
        disable_irq(qup->irq);
        qup->msg = NULL;

        return ret;
}

static int qup_i2c_read_one(struct qup_i2c_dev *qup, struct i2c_msg *msg)
{
        int ret;

        qup->msg = msg;
        qup->pos  = 0;

        enable_irq(qup->irq);
        qup_i2c_set_read_mode(qup, msg->len);

        ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
        if (ret)
                goto err;

        writel(qup->clk_ctl, qup->base + QUP_I2C_CLK_CTL);

        ret = qup_i2c_change_state(qup, QUP_PAUSE_STATE);
        if (ret)
                goto err;

        qup_i2c_issue_read(qup, msg);

        ret = qup_i2c_change_state(qup, QUP_RUN_STATE);
        if (ret)
                goto err;

        do {
                ret = qup_i2c_wait_for_complete(qup, msg);
                if (ret)
                        goto err;

                ret = qup_i2c_read_fifo(qup, msg);
                if (ret)
                        goto err;
        } while (qup->pos < msg->len);

err:
        disable_irq(qup->irq);
        qup->msg = NULL;

        return ret;
}

static int qup_i2c_xfer(struct i2c_adapter *adap,
                        struct i2c_msg msgs[],
                        int num)
{
        struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
        int ret, idx;

        ret = pm_runtime_get_sync(qup->dev);
        if (ret < 0)
                goto out;

        qup->bus_err = 0;
        qup->qup_err = 0;

        writel(1, qup->base + QUP_SW_RESET);
        ret = qup_i2c_poll_state(qup, QUP_RESET_STATE);
        if (ret)
                goto out;

        /* Configure QUP as I2C mini core */
        writel(I2C_MINI_CORE | I2C_N_VAL, qup->base + QUP_CONFIG);

        for (idx = 0; idx < num; idx++) {
                if (msgs[idx].len == 0) {
                        ret = -EINVAL;
                        goto out;
                }

                if (qup_i2c_poll_state_i2c_master(qup)) {
                        ret = -EIO;
                        goto out;
                }

                if (qup_i2c_check_msg_len(&msgs[idx])) {
                        ret = -EINVAL;
                        goto out;
                }

                if (msgs[idx].flags & I2C_M_RD)
                        ret = qup_i2c_read_one(qup, &msgs[idx]);
                else
                        ret = qup_i2c_write_one(qup, &msgs[idx]);

                if (ret)
                        break;

                ret = qup_i2c_change_state(qup, QUP_RESET_STATE);
                if (ret)
                        break;
        }

        if (ret == 0)
                ret = num;
out:

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

        return ret;
}

static int qup_i2c_xfer_v2(struct i2c_adapter *adap,
                           struct i2c_msg msgs[],
                           int num)
{
        struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
        int ret, len, idx = 0, use_dma = 0;

        qup->bus_err = 0;
        qup->qup_err = 0;

        ret = pm_runtime_get_sync(qup->dev);
        if (ret < 0)
                goto out;

        writel(1, qup->base + QUP_SW_RESET);
        ret = qup_i2c_poll_state(qup, QUP_RESET_STATE);
        if (ret)
                goto out;

        /* Configure QUP as I2C mini core */
        writel(I2C_MINI_CORE | I2C_N_VAL_V2, qup->base + QUP_CONFIG);
        writel(QUP_V2_TAGS_EN, qup->base + QUP_I2C_MASTER_GEN);

        if ((qup->is_dma)) {
                /* All i2c_msgs should be transferred using either dma or cpu */
                for (idx = 0; idx < num; idx++) {
                        if (msgs[idx].len == 0) {
                                ret = -EINVAL;
                                goto out;
                        }

                        len = (msgs[idx].len > qup->out_fifo_sz) ||
                              (msgs[idx].len > qup->in_fifo_sz);

                        if ((!is_vmalloc_addr(msgs[idx].buf)) && len) {
                                use_dma = 1;
                         } else {
                                use_dma = 0;
                                break;
                        }
                }
        }

        idx = 0;

        do {
                if (msgs[idx].len == 0) {
                        ret = -EINVAL;
                        goto out;
                }

                if (qup_i2c_poll_state_i2c_master(qup)) {
                        ret = -EIO;
                        goto out;
                }

                qup->is_last = (idx == (num - 1));
                if (idx)
                        qup->config_run = QUP_I2C_MX_CONFIG_DURING_RUN;
                else
                        qup->config_run = 0;

                reinit_completion(&qup->xfer);

                if (use_dma) {
                        ret = qup_i2c_bam_xfer(adap, &msgs[idx], num);
                } else {
                        if (msgs[idx].flags & I2C_M_RD)
                                ret = qup_i2c_read_one_v2(qup, &msgs[idx]);
                        else
                                ret = qup_i2c_write_one_v2(qup, &msgs[idx]);
                }
        } while ((idx++ < (num - 1)) && !use_dma && !ret);

        if (!ret)
                ret = qup_i2c_change_state(qup, QUP_RESET_STATE);

        if (ret == 0)
                ret = num;
out:
        pm_runtime_mark_last_busy(qup->dev);
        pm_runtime_put_autosuspend(qup->dev);

        return ret;
}

static u32 qup_i2c_func(struct i2c_adapter *adap)
{
        return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}

static const struct i2c_algorithm qup_i2c_algo = {
        .master_xfer    = qup_i2c_xfer,
        .functionality  = qup_i2c_func,
};

static const struct i2c_algorithm qup_i2c_algo_v2 = {
        .master_xfer    = qup_i2c_xfer_v2,
        .functionality  = qup_i2c_func,
};

/*
 * The QUP block will issue a NACK and STOP on the bus when reaching
 * the end of the read, the length of the read is specified as one byte
 * which limits the possible read to 256 (QUP_READ_LIMIT) bytes.
 */
static const struct i2c_adapter_quirks qup_i2c_quirks = {
        .max_read_len = QUP_READ_LIMIT,
};

static void qup_i2c_enable_clocks(struct qup_i2c_dev *qup)
{
        clk_prepare_enable(qup->clk);
        clk_prepare_enable(qup->pclk);
}

static void qup_i2c_disable_clocks(struct qup_i2c_dev *qup)
{
        u32 config;

        qup_i2c_change_state(qup, QUP_RESET_STATE);
        clk_disable_unprepare(qup->clk);
        config = readl(qup->base + QUP_CONFIG);
        config |= QUP_CLOCK_AUTO_GATE;
        writel(config, qup->base + QUP_CONFIG);
        clk_disable_unprepare(qup->pclk);
}

static int qup_i2c_probe(struct platform_device *pdev)
{
        static const int blk_sizes[] = {4, 16, 32};
        struct qup_i2c_dev *qup;
        unsigned long one_bit_t;
        struct resource *res;
        u32 io_mode, hw_ver, size;
        int ret, fs_div, hs_div;
        u32 src_clk_freq = DEFAULT_SRC_CLK;
        u32 clk_freq = DEFAULT_CLK_FREQ;
        int blocks;

        qup = devm_kzalloc(&pdev->dev, sizeof(*qup), GFP_KERNEL);
        if (!qup)
                return -ENOMEM;

        qup->dev = &pdev->dev;
        init_completion(&qup->xfer);
        platform_set_drvdata(pdev, qup);

        ret = device_property_read_u32(qup->dev, "clock-frequency", &clk_freq);
        if (ret) {
                dev_notice(qup->dev, "using default clock-frequency %d",
                        DEFAULT_CLK_FREQ);
        }

        if (of_device_is_compatible(pdev->dev.of_node, "qcom,i2c-qup-v1.1.1")) {
                qup->adap.algo = &qup_i2c_algo;
                qup->adap.quirks = &qup_i2c_quirks;
        } else {
                qup->adap.algo = &qup_i2c_algo_v2;
                ret = qup_i2c_req_dma(qup);

                if (ret == -EPROBE_DEFER)
                        goto fail_dma;
                else if (ret != 0)
                        goto nodma;

                blocks = (MX_BLOCKS << 1) + 1;
                qup->btx.sg = devm_kzalloc(&pdev->dev,
                                           sizeof(*qup->btx.sg) * blocks,
                                           GFP_KERNEL);
                if (!qup->btx.sg) {
                        ret = -ENOMEM;
                        goto fail_dma;
                }
                sg_init_table(qup->btx.sg, blocks);

                qup->brx.sg = devm_kzalloc(&pdev->dev,
                                           sizeof(*qup->brx.sg) * blocks,
                                           GFP_KERNEL);
                if (!qup->brx.sg) {
                        ret = -ENOMEM;
                        goto fail_dma;
                }
                sg_init_table(qup->brx.sg, blocks);

                /* 2 tag bytes for each block + 5 for start, stop tags */
                size = blocks * 2 + 5;

                qup->start_tag.start = devm_kzalloc(&pdev->dev,
                                                    size, GFP_KERNEL);
                if (!qup->start_tag.start) {
                        ret = -ENOMEM;
                        goto fail_dma;
                }

                qup->brx.tag.start = devm_kzalloc(&pdev->dev, 2, GFP_KERNEL);
                if (!qup->brx.tag.start) {
                        ret = -ENOMEM;
                        goto fail_dma;
                }

                qup->btx.tag.start = devm_kzalloc(&pdev->dev, 2, GFP_KERNEL);
                if (!qup->btx.tag.start) {
                        ret = -ENOMEM;
                        goto fail_dma;
                }
                qup->is_dma = true;
        }

nodma:
        /* We support frequencies up to FAST Mode (400KHz) */
        if (!clk_freq || clk_freq > 400000) {
                dev_err(qup->dev, "clock frequency not supported %d\n",
                        clk_freq);
                return -EINVAL;
        }

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        qup->base = devm_ioremap_resource(qup->dev, res);
        if (IS_ERR(qup->base))
                return PTR_ERR(qup->base);

        qup->irq = platform_get_irq(pdev, 0);
        if (qup->irq < 0) {
                dev_err(qup->dev, "No IRQ defined\n");
                return qup->irq;
        }

        if (has_acpi_companion(qup->dev)) {
                ret = device_property_read_u32(qup->dev,
                                "src-clock-hz", &src_clk_freq);
                if (ret) {
                        dev_notice(qup->dev, "using default src-clock-hz %d",
                                DEFAULT_SRC_CLK);
                }
                ACPI_COMPANION_SET(&qup->adap.dev, ACPI_COMPANION(qup->dev));
        } else {
                qup->clk = devm_clk_get(qup->dev, "core");
                if (IS_ERR(qup->clk)) {
                        dev_err(qup->dev, "Could not get core clock\n");
                        return PTR_ERR(qup->clk);
                }

                qup->pclk = devm_clk_get(qup->dev, "iface");
                if (IS_ERR(qup->pclk)) {
                        dev_err(qup->dev, "Could not get iface clock\n");
                        return PTR_ERR(qup->pclk);
                }
                qup_i2c_enable_clocks(qup);
                src_clk_freq = clk_get_rate(qup->clk);
        }

        /*
         * Bootloaders might leave a pending interrupt on certain QUP's,
         * so we reset the core before registering for interrupts.
         */
        writel(1, qup->base + QUP_SW_RESET);
        ret = qup_i2c_poll_state_valid(qup);
        if (ret)
                goto fail;

        ret = devm_request_irq(qup->dev, qup->irq, qup_i2c_interrupt,
                               IRQF_TRIGGER_HIGH, "i2c_qup", qup);
        if (ret) {
                dev_err(qup->dev, "Request %d IRQ failed\n", qup->irq);
                goto fail;
        }
        disable_irq(qup->irq);

        hw_ver = readl(qup->base + QUP_HW_VERSION);
        dev_dbg(qup->dev, "Revision %x\n", hw_ver);

        io_mode = readl(qup->base + QUP_IO_MODE);

        /*
         * The block/fifo size w.r.t. 'actual data' is 1/2 due to 'tag'
         * associated with each byte written/received
         */
        size = QUP_OUTPUT_BLOCK_SIZE(io_mode);
        if (size >= ARRAY_SIZE(blk_sizes)) {
                ret = -EIO;
                goto fail;
        }
        qup->out_blk_sz = blk_sizes[size] / 2;

        size = QUP_INPUT_BLOCK_SIZE(io_mode);
        if (size >= ARRAY_SIZE(blk_sizes)) {
                ret = -EIO;
                goto fail;
        }
        qup->in_blk_sz = blk_sizes[size] / 2;

        size = QUP_OUTPUT_FIFO_SIZE(io_mode);
        qup->out_fifo_sz = qup->out_blk_sz * (2 << size);

        size = QUP_INPUT_FIFO_SIZE(io_mode);
        qup->in_fifo_sz = qup->in_blk_sz * (2 << size);

        fs_div = ((src_clk_freq / clk_freq) / 2) - 3;
        hs_div = 3;
        qup->clk_ctl = (hs_div << 8) | (fs_div & 0xff);

        /*
         * Time it takes for a byte to be clocked out on the bus.
         * Each byte takes 9 clock cycles (8 bits + 1 ack).
         */
        one_bit_t = (USEC_PER_SEC / clk_freq) + 1;
        qup->one_byte_t = one_bit_t * 9;

        dev_dbg(qup->dev, "IN:block:%d, fifo:%d, OUT:block:%d, fifo:%d\n",
                qup->in_blk_sz, qup->in_fifo_sz,
                qup->out_blk_sz, qup->out_fifo_sz);

        i2c_set_adapdata(&qup->adap, qup);
        qup->adap.dev.parent = qup->dev;
        qup->adap.dev.of_node = pdev->dev.of_node;
        qup->is_last = true;

        strlcpy(qup->adap.name, "QUP I2C adapter", sizeof(qup->adap.name));

        pm_runtime_set_autosuspend_delay(qup->dev, MSEC_PER_SEC);
        pm_runtime_use_autosuspend(qup->dev);
        pm_runtime_set_active(qup->dev);
        pm_runtime_enable(qup->dev);

        ret = i2c_add_adapter(&qup->adap);
        if (ret)
                goto fail_runtime;

        return 0;

fail_runtime:
        pm_runtime_disable(qup->dev);
        pm_runtime_set_suspended(qup->dev);
fail:
        qup_i2c_disable_clocks(qup);
fail_dma:
        if (qup->btx.dma)
                dma_release_channel(qup->btx.dma);
        if (qup->brx.dma)
                dma_release_channel(qup->brx.dma);
        return ret;
}

static int qup_i2c_remove(struct platform_device *pdev)
{
        struct qup_i2c_dev *qup = platform_get_drvdata(pdev);

        if (qup->is_dma) {
                dma_release_channel(qup->btx.dma);
                dma_release_channel(qup->brx.dma);
        }

        disable_irq(qup->irq);
        qup_i2c_disable_clocks(qup);
        i2c_del_adapter(&qup->adap);
        pm_runtime_disable(qup->dev);
        pm_runtime_set_suspended(qup->dev);
        return 0;
}

#ifdef CONFIG_PM
static int qup_i2c_pm_suspend_runtime(struct device *device)
{
        struct qup_i2c_dev *qup = dev_get_drvdata(device);

        dev_dbg(device, "pm_runtime: suspending...\n");
        qup_i2c_disable_clocks(qup);
        return 0;
}

static int qup_i2c_pm_resume_runtime(struct device *device)
{
        struct qup_i2c_dev *qup = dev_get_drvdata(device);

        dev_dbg(device, "pm_runtime: resuming...\n");
        qup_i2c_enable_clocks(qup);
        return 0;
}
#endif

#ifdef CONFIG_PM_SLEEP
static int qup_i2c_suspend(struct device *device)
{
        if (!pm_runtime_suspended(device))
                return qup_i2c_pm_suspend_runtime(device);
        return 0;
}

static int qup_i2c_resume(struct device *device)
{
        qup_i2c_pm_resume_runtime(device);
        pm_runtime_mark_last_busy(device);
        pm_request_autosuspend(device);
        return 0;
}
#endif

static const struct dev_pm_ops qup_i2c_qup_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(
                qup_i2c_suspend,
                qup_i2c_resume)
        SET_RUNTIME_PM_OPS(
                qup_i2c_pm_suspend_runtime,
                qup_i2c_pm_resume_runtime,
                NULL)
};

static const struct of_device_id qup_i2c_dt_match[] = {
        { .compatible = "qcom,i2c-qup-v1.1.1" },
        { .compatible = "qcom,i2c-qup-v2.1.1" },
        { .compatible = "qcom,i2c-qup-v2.2.1" },
        {}
};
MODULE_DEVICE_TABLE(of, qup_i2c_dt_match);

#if IS_ENABLED(CONFIG_ACPI)
static const struct acpi_device_id qup_i2c_acpi_match[] = {
        { "QCOM8010"},
        { },
};
MODULE_DEVICE_TABLE(acpi, qup_i2c_acpi_match);
#endif

static struct platform_driver qup_i2c_driver = {
        .probe  = qup_i2c_probe,
        .remove = qup_i2c_remove,
        .driver = {
                .name = "i2c_qup",
                .pm = &qup_i2c_qup_pm_ops,
                .of_match_table = qup_i2c_dt_match,
                .acpi_match_table = ACPI_PTR(qup_i2c_acpi_match),
        },
};

module_platform_driver(qup_i2c_driver);

MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c_qup");