/*
 * Copyright (C) 2009 Samsung Electronics Ltd.
 *      Jaswinder Singh <jassi.brar@samsung.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/init.h>
#include <linux/module.h>
#include <linux/workqueue.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/gpio.h>
#include <linux/of.h>
#include <linux/of_gpio.h>

#include <mach/dma.h>
#include <linux/platform_data/spi-s3c64xx.h>

#define MAX_SPI_PORTS           3

/* Registers and bit-fields */

#define S3C64XX_SPI_CH_CFG              0x00
#define S3C64XX_SPI_CLK_CFG             0x04
#define S3C64XX_SPI_MODE_CFG    0x08
#define S3C64XX_SPI_SLAVE_SEL   0x0C
#define S3C64XX_SPI_INT_EN              0x10
#define S3C64XX_SPI_STATUS              0x14
#define S3C64XX_SPI_TX_DATA             0x18
#define S3C64XX_SPI_RX_DATA             0x1C
#define S3C64XX_SPI_PACKET_CNT  0x20
#define S3C64XX_SPI_PENDING_CLR 0x24
#define S3C64XX_SPI_SWAP_CFG    0x28
#define S3C64XX_SPI_FB_CLK              0x2C

#define S3C64XX_SPI_CH_HS_EN            (1<<6)  /* High Speed Enable */
#define S3C64XX_SPI_CH_SW_RST           (1<<5)
#define S3C64XX_SPI_CH_SLAVE            (1<<4)
#define S3C64XX_SPI_CPOL_L              (1<<3)
#define S3C64XX_SPI_CPHA_B              (1<<2)
#define S3C64XX_SPI_CH_RXCH_ON          (1<<1)
#define S3C64XX_SPI_CH_TXCH_ON          (1<<0)

#define S3C64XX_SPI_CLKSEL_SRCMSK       (3<<9)
#define S3C64XX_SPI_CLKSEL_SRCSHFT      9
#define S3C64XX_SPI_ENCLK_ENABLE        (1<<8)
#define S3C64XX_SPI_PSR_MASK            0xff

#define S3C64XX_SPI_MODE_CH_TSZ_BYTE            (0<<29)
#define S3C64XX_SPI_MODE_CH_TSZ_HALFWORD        (1<<29)
#define S3C64XX_SPI_MODE_CH_TSZ_WORD            (2<<29)
#define S3C64XX_SPI_MODE_CH_TSZ_MASK            (3<<29)
#define S3C64XX_SPI_MODE_BUS_TSZ_BYTE           (0<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_HALFWORD       (1<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_WORD           (2<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_MASK           (3<<17)
#define S3C64XX_SPI_MODE_RXDMA_ON               (1<<2)
#define S3C64XX_SPI_MODE_TXDMA_ON               (1<<1)
#define S3C64XX_SPI_MODE_4BURST                 (1<<0)

#define S3C64XX_SPI_SLAVE_AUTO                  (1<<1)
#define S3C64XX_SPI_SLAVE_SIG_INACT             (1<<0)

#define S3C64XX_SPI_INT_TRAILING_EN             (1<<6)
#define S3C64XX_SPI_INT_RX_OVERRUN_EN           (1<<5)
#define S3C64XX_SPI_INT_RX_UNDERRUN_EN          (1<<4)
#define S3C64XX_SPI_INT_TX_OVERRUN_EN           (1<<3)
#define S3C64XX_SPI_INT_TX_UNDERRUN_EN          (1<<2)
#define S3C64XX_SPI_INT_RX_FIFORDY_EN           (1<<1)
#define S3C64XX_SPI_INT_TX_FIFORDY_EN           (1<<0)

#define S3C64XX_SPI_ST_RX_OVERRUN_ERR           (1<<5)
#define S3C64XX_SPI_ST_RX_UNDERRUN_ERR  (1<<4)
#define S3C64XX_SPI_ST_TX_OVERRUN_ERR           (1<<3)
#define S3C64XX_SPI_ST_TX_UNDERRUN_ERR  (1<<2)
#define S3C64XX_SPI_ST_RX_FIFORDY               (1<<1)
#define S3C64XX_SPI_ST_TX_FIFORDY               (1<<0)

#define S3C64XX_SPI_PACKET_CNT_EN               (1<<16)

#define S3C64XX_SPI_PND_TX_UNDERRUN_CLR         (1<<4)
#define S3C64XX_SPI_PND_TX_OVERRUN_CLR          (1<<3)
#define S3C64XX_SPI_PND_RX_UNDERRUN_CLR         (1<<2)
#define S3C64XX_SPI_PND_RX_OVERRUN_CLR          (1<<1)
#define S3C64XX_SPI_PND_TRAILING_CLR            (1<<0)

#define S3C64XX_SPI_SWAP_RX_HALF_WORD           (1<<7)
#define S3C64XX_SPI_SWAP_RX_BYTE                (1<<6)
#define S3C64XX_SPI_SWAP_RX_BIT                 (1<<5)
#define S3C64XX_SPI_SWAP_RX_EN                  (1<<4)
#define S3C64XX_SPI_SWAP_TX_HALF_WORD           (1<<3)
#define S3C64XX_SPI_SWAP_TX_BYTE                (1<<2)
#define S3C64XX_SPI_SWAP_TX_BIT                 (1<<1)
#define S3C64XX_SPI_SWAP_TX_EN                  (1<<0)

#define S3C64XX_SPI_FBCLK_MSK           (3<<0)

#define FIFO_LVL_MASK(i) ((i)->port_conf->fifo_lvl_mask[i->port_id])
#define S3C64XX_SPI_ST_TX_DONE(v, i) (((v) & \
                                (1 << (i)->port_conf->tx_st_done)) ? 1 : 0)
#define TX_FIFO_LVL(v, i) (((v) >> 6) & FIFO_LVL_MASK(i))
#define RX_FIFO_LVL(v, i) (((v) >> (i)->port_conf->rx_lvl_offset) & \
                                        FIFO_LVL_MASK(i))

#define S3C64XX_SPI_MAX_TRAILCNT        0x3ff
#define S3C64XX_SPI_TRAILCNT_OFF        19

#define S3C64XX_SPI_TRAILCNT            S3C64XX_SPI_MAX_TRAILCNT

#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)

#define RXBUSY    (1<<2)
#define TXBUSY    (1<<3)

struct s3c64xx_spi_dma_data {
        unsigned                ch;
        enum dma_transfer_direction direction;
        enum dma_ch     dmach;
};

/**
 * struct s3c64xx_spi_info - SPI Controller hardware info
 * @fifo_lvl_mask: Bit-mask for {TX|RX}_FIFO_LVL bits in SPI_STATUS register.
 * @rx_lvl_offset: Bit offset of RX_FIFO_LVL bits in SPI_STATUS regiter.
 * @tx_st_done: Bit offset of TX_DONE bit in SPI_STATUS regiter.
 * @high_speed: True, if the controller supports HIGH_SPEED_EN bit.
 * @clk_from_cmu: True, if the controller does not include a clock mux and
 *      prescaler unit.
 *
 * The Samsung s3c64xx SPI controller are used on various Samsung SoC's but
 * differ in some aspects such as the size of the fifo and spi bus clock
 * setup. Such differences are specified to the driver using this structure
 * which is provided as driver data to the driver.
 */
struct s3c64xx_spi_port_config {
        int     fifo_lvl_mask[MAX_SPI_PORTS];
        int     rx_lvl_offset;
        int     tx_st_done;
        bool    high_speed;
        bool    clk_from_cmu;
};

/**
 * struct s3c64xx_spi_driver_data - Runtime info holder for SPI driver.
 * @clk: Pointer to the spi clock.
 * @src_clk: Pointer to the clock used to generate SPI signals.
 * @master: Pointer to the SPI Protocol master.
 * @cntrlr_info: Platform specific data for the controller this driver manages.
 * @tgl_spi: Pointer to the last CS left untoggled by the cs_change hint.
 * @queue: To log SPI xfer requests.
 * @lock: Controller specific lock.
 * @state: Set of FLAGS to indicate status.
 * @rx_dmach: Controller's DMA channel for Rx.
 * @tx_dmach: Controller's DMA channel for Tx.
 * @sfr_start: BUS address of SPI controller regs.
 * @regs: Pointer to ioremap'ed controller registers.
 * @irq: interrupt
 * @xfer_completion: To indicate completion of xfer task.
 * @cur_mode: Stores the active configuration of the controller.
 * @cur_bpw: Stores the active bits per word settings.
 * @cur_speed: Stores the active xfer clock speed.
 */
struct s3c64xx_spi_driver_data {
        void __iomem                    *regs;
        struct clk                      *clk;
        struct clk                      *src_clk;
        struct platform_device          *pdev;
        struct spi_master               *master;
        struct s3c64xx_spi_info  *cntrlr_info;
        struct spi_device               *tgl_spi;
        struct list_head                queue;
        spinlock_t                      lock;
        unsigned long                   sfr_start;
        struct completion               xfer_completion;
        unsigned                        state;
        unsigned                        cur_mode, cur_bpw;
        unsigned                        cur_speed;
        struct s3c64xx_spi_dma_data     rx_dma;
        struct s3c64xx_spi_dma_data     tx_dma;
        struct samsung_dma_ops          *ops;
        struct s3c64xx_spi_port_config  *port_conf;
        unsigned int                    port_id;
        unsigned long                   gpios[4];
};

static struct s3c2410_dma_client s3c64xx_spi_dma_client = {
        .name = "samsung-spi-dma",
};

static void flush_fifo(struct s3c64xx_spi_driver_data *sdd)
{
        void __iomem *regs = sdd->regs;
        unsigned long loops;
        u32 val;

        writel(0, regs + S3C64XX_SPI_PACKET_CNT);

        val = readl(regs + S3C64XX_SPI_CH_CFG);
        val &= ~(S3C64XX_SPI_CH_RXCH_ON | S3C64XX_SPI_CH_TXCH_ON);
        writel(val, regs + S3C64XX_SPI_CH_CFG);

        val = readl(regs + S3C64XX_SPI_CH_CFG);
        val |= S3C64XX_SPI_CH_SW_RST;
        val &= ~S3C64XX_SPI_CH_HS_EN;
        writel(val, regs + S3C64XX_SPI_CH_CFG);

        /* Flush TxFIFO*/
        loops = msecs_to_loops(1);
        do {
                val = readl(regs + S3C64XX_SPI_STATUS);
        } while (TX_FIFO_LVL(val, sdd) && loops--);

        if (loops == 0)
                dev_warn(&sdd->pdev->dev, "Timed out flushing TX FIFO\n");

        /* Flush RxFIFO*/
        loops = msecs_to_loops(1);
        do {
                val = readl(regs + S3C64XX_SPI_STATUS);
                if (RX_FIFO_LVL(val, sdd))
                        readl(regs + S3C64XX_SPI_RX_DATA);
                else
                        break;
        } while (loops--);

        if (loops == 0)
                dev_warn(&sdd->pdev->dev, "Timed out flushing RX FIFO\n");

        val = readl(regs + S3C64XX_SPI_CH_CFG);
        val &= ~S3C64XX_SPI_CH_SW_RST;
        writel(val, regs + S3C64XX_SPI_CH_CFG);

        val = readl(regs + S3C64XX_SPI_MODE_CFG);
        val &= ~(S3C64XX_SPI_MODE_TXDMA_ON | S3C64XX_SPI_MODE_RXDMA_ON);
        writel(val, regs + S3C64XX_SPI_MODE_CFG);
}

static void s3c64xx_spi_dmacb(void *data)
{
        struct s3c64xx_spi_driver_data *sdd;
        struct s3c64xx_spi_dma_data *dma = data;
        unsigned long flags;

        if (dma->direction == DMA_DEV_TO_MEM)
                sdd = container_of(data,
                        struct s3c64xx_spi_driver_data, rx_dma);
        else
                sdd = container_of(data,
                        struct s3c64xx_spi_driver_data, tx_dma);

        spin_lock_irqsave(&sdd->lock, flags);

        if (dma->direction == DMA_DEV_TO_MEM) {
                sdd->state &= ~RXBUSY;
                if (!(sdd->state & TXBUSY))
                        complete(&sdd->xfer_completion);
        } else {
                sdd->state &= ~TXBUSY;
                if (!(sdd->state & RXBUSY))
                        complete(&sdd->xfer_completion);
        }

        spin_unlock_irqrestore(&sdd->lock, flags);
}

static void prepare_dma(struct s3c64xx_spi_dma_data *dma,
                                        unsigned len, dma_addr_t buf)
{
        struct s3c64xx_spi_driver_data *sdd;
        struct samsung_dma_prep info;
        struct samsung_dma_config config;

        if (dma->direction == DMA_DEV_TO_MEM) {
                sdd = container_of((void *)dma,
                        struct s3c64xx_spi_driver_data, rx_dma);
                config.direction = sdd->rx_dma.direction;
                config.fifo = sdd->sfr_start + S3C64XX_SPI_RX_DATA;
                config.width = sdd->cur_bpw / 8;
                sdd->ops->config(sdd->rx_dma.ch, &config);
        } else {
                sdd = container_of((void *)dma,
                        struct s3c64xx_spi_driver_data, tx_dma);
                config.direction =  sdd->tx_dma.direction;
                config.fifo = sdd->sfr_start + S3C64XX_SPI_TX_DATA;
                config.width = sdd->cur_bpw / 8;
                sdd->ops->config(sdd->tx_dma.ch, &config);
        }

        info.cap = DMA_SLAVE;
        info.len = len;
        info.fp = s3c64xx_spi_dmacb;
        info.fp_param = dma;
        info.direction = dma->direction;
        info.buf = buf;

        sdd->ops->prepare(dma->ch, &info);
        sdd->ops->trigger(dma->ch);
}

static int acquire_dma(struct s3c64xx_spi_driver_data *sdd)
{
        struct samsung_dma_req req;
        struct device *dev = &sdd->pdev->dev;

        sdd->ops = samsung_dma_get_ops();

        req.cap = DMA_SLAVE;
        req.client = &s3c64xx_spi_dma_client;

        sdd->rx_dma.ch = sdd->ops->request(sdd->rx_dma.dmach, &req, dev, "rx");
        sdd->tx_dma.ch = sdd->ops->request(sdd->tx_dma.dmach, &req, dev, "tx");

        return 1;
}

static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
                                struct spi_device *spi,
                                struct spi_transfer *xfer, int dma_mode)
{
        void __iomem *regs = sdd->regs;
        u32 modecfg, chcfg;

        modecfg = readl(regs + S3C64XX_SPI_MODE_CFG);
        modecfg &= ~(S3C64XX_SPI_MODE_TXDMA_ON | S3C64XX_SPI_MODE_RXDMA_ON);

        chcfg = readl(regs + S3C64XX_SPI_CH_CFG);
        chcfg &= ~S3C64XX_SPI_CH_TXCH_ON;

        if (dma_mode) {
                chcfg &= ~S3C64XX_SPI_CH_RXCH_ON;
        } else {
                /* Always shift in data in FIFO, even if xfer is Tx only,
                 * this helps setting PCKT_CNT value for generating clocks
                 * as exactly needed.
                 */
                chcfg |= S3C64XX_SPI_CH_RXCH_ON;
                writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
                                        | S3C64XX_SPI_PACKET_CNT_EN,
                                        regs + S3C64XX_SPI_PACKET_CNT);
        }

        if (xfer->tx_buf != NULL) {
                sdd->state |= TXBUSY;
                chcfg |= S3C64XX_SPI_CH_TXCH_ON;
                if (dma_mode) {
                        modecfg |= S3C64XX_SPI_MODE_TXDMA_ON;
                        prepare_dma(&sdd->tx_dma, xfer->len, xfer->tx_dma);
                } else {
                        switch (sdd->cur_bpw) {
                        case 32:
                                iowrite32_rep(regs + S3C64XX_SPI_TX_DATA,
                                        xfer->tx_buf, xfer->len / 4);
                                break;
                        case 16:
                                iowrite16_rep(regs + S3C64XX_SPI_TX_DATA,
                                        xfer->tx_buf, xfer->len / 2);
                                break;
                        default:
                                iowrite8_rep(regs + S3C64XX_SPI_TX_DATA,
                                        xfer->tx_buf, xfer->len);
                                break;
                        }
                }
        }

        if (xfer->rx_buf != NULL) {
                sdd->state |= RXBUSY;

                if (sdd->port_conf->high_speed && sdd->cur_speed >= 30000000UL
                                        && !(sdd->cur_mode & SPI_CPHA))
                        chcfg |= S3C64XX_SPI_CH_HS_EN;

                if (dma_mode) {
                        modecfg |= S3C64XX_SPI_MODE_RXDMA_ON;
                        chcfg |= S3C64XX_SPI_CH_RXCH_ON;
                        writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
                                        | S3C64XX_SPI_PACKET_CNT_EN,
                                        regs + S3C64XX_SPI_PACKET_CNT);
                        prepare_dma(&sdd->rx_dma, xfer->len, xfer->rx_dma);
                }
        }

        writel(modecfg, regs + S3C64XX_SPI_MODE_CFG);
        writel(chcfg, regs + S3C64XX_SPI_CH_CFG);
}

static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd,
                                                struct spi_device *spi)
{
        struct s3c64xx_spi_csinfo *cs;

        if (sdd->tgl_spi != NULL) { /* If last device toggled after mssg */
                if (sdd->tgl_spi != spi) { /* if last mssg on diff device */
                        /* Deselect the last toggled device */
                        cs = sdd->tgl_spi->controller_data;
                        gpio_set_value(cs->line,
                                spi->mode & SPI_CS_HIGH ? 0 : 1);
                }
                sdd->tgl_spi = NULL;
        }

        cs = spi->controller_data;
        gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0);
}

static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
                                struct spi_transfer *xfer, int dma_mode)
{
        void __iomem *regs = sdd->regs;
        unsigned long val;
        int ms;

        /* millisecs to xfer 'len' bytes @ 'cur_speed' */
        ms = xfer->len * 8 * 1000 / sdd->cur_speed;
        ms += 10; /* some tolerance */

        if (dma_mode) {
                val = msecs_to_jiffies(ms) + 10;
                val = wait_for_completion_timeout(&sdd->xfer_completion, val);
        } else {
                u32 status;
                val = msecs_to_loops(ms);
                do {
                        status = readl(regs + S3C64XX_SPI_STATUS);
                } while (RX_FIFO_LVL(status, sdd) < xfer->len && --val);
        }

        if (!val)
                return -EIO;

        if (dma_mode) {
                u32 status;

                /*
                 * DmaTx returns after simply writing data in the FIFO,
                 * w/o waiting for real transmission on the bus to finish.
                 * DmaRx returns only after Dma read data from FIFO which
                 * needs bus transmission to finish, so we don't worry if
                 * Xfer involved Rx(with or without Tx).
                 */
                if (xfer->rx_buf == NULL) {
                        val = msecs_to_loops(10);
                        status = readl(regs + S3C64XX_SPI_STATUS);
                        while ((TX_FIFO_LVL(status, sdd)
                                || !S3C64XX_SPI_ST_TX_DONE(status, sdd))
                                        && --val) {
                                cpu_relax();
                                status = readl(regs + S3C64XX_SPI_STATUS);
                        }

                        if (!val)
                                return -EIO;
                }
        } else {
                /* If it was only Tx */
                if (xfer->rx_buf == NULL) {
                        sdd->state &= ~TXBUSY;
                        return 0;
                }

                switch (sdd->cur_bpw) {
                case 32:
                        ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
                                xfer->rx_buf, xfer->len / 4);
                        break;
                case 16:
                        ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
                                xfer->rx_buf, xfer->len / 2);
                        break;
                default:
                        ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
                                xfer->rx_buf, xfer->len);
                        break;
                }
                sdd->state &= ~RXBUSY;
        }

        return 0;
}

static inline void disable_cs(struct s3c64xx_spi_driver_data *sdd,
                                                struct spi_device *spi)
{
        struct s3c64xx_spi_csinfo *cs = spi->controller_data;

        if (sdd->tgl_spi == spi)
                sdd->tgl_spi = NULL;

        gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1);
}

static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
{
        void __iomem *regs = sdd->regs;
        u32 val;

        /* Disable Clock */
        if (sdd->port_conf->clk_from_cmu) {
                clk_disable_unprepare(sdd->src_clk);
        } else {
                val = readl(regs + S3C64XX_SPI_CLK_CFG);
                val &= ~S3C64XX_SPI_ENCLK_ENABLE;
                writel(val, regs + S3C64XX_SPI_CLK_CFG);
        }

        /* Set Polarity and Phase */
        val = readl(regs + S3C64XX_SPI_CH_CFG);
        val &= ~(S3C64XX_SPI_CH_SLAVE |
                        S3C64XX_SPI_CPOL_L |
                        S3C64XX_SPI_CPHA_B);

        if (sdd->cur_mode & SPI_CPOL)
                val |= S3C64XX_SPI_CPOL_L;

        if (sdd->cur_mode & SPI_CPHA)
                val |= S3C64XX_SPI_CPHA_B;

        writel(val, regs + S3C64XX_SPI_CH_CFG);

        /* Set Channel & DMA Mode */
        val = readl(regs + S3C64XX_SPI_MODE_CFG);
        val &= ~(S3C64XX_SPI_MODE_BUS_TSZ_MASK
                        | S3C64XX_SPI_MODE_CH_TSZ_MASK);

        switch (sdd->cur_bpw) {
        case 32:
                val |= S3C64XX_SPI_MODE_BUS_TSZ_WORD;
                val |= S3C64XX_SPI_MODE_CH_TSZ_WORD;
                break;
        case 16:
                val |= S3C64XX_SPI_MODE_BUS_TSZ_HALFWORD;
                val |= S3C64XX_SPI_MODE_CH_TSZ_HALFWORD;
                break;
        default:
                val |= S3C64XX_SPI_MODE_BUS_TSZ_BYTE;
                val |= S3C64XX_SPI_MODE_CH_TSZ_BYTE;
                break;
        }

        writel(val, regs + S3C64XX_SPI_MODE_CFG);

        if (sdd->port_conf->clk_from_cmu) {
                /* Configure Clock */
                /* There is half-multiplier before the SPI */
                clk_set_rate(sdd->src_clk, sdd->cur_speed * 2);
                /* Enable Clock */
                clk_prepare_enable(sdd->src_clk);
        } else {
                /* Configure Clock */
                val = readl(regs + S3C64XX_SPI_CLK_CFG);
                val &= ~S3C64XX_SPI_PSR_MASK;
                val |= ((clk_get_rate(sdd->src_clk) / sdd->cur_speed / 2 - 1)
                                & S3C64XX_SPI_PSR_MASK);
                writel(val, regs + S3C64XX_SPI_CLK_CFG);

                /* Enable Clock */
                val = readl(regs + S3C64XX_SPI_CLK_CFG);
                val |= S3C64XX_SPI_ENCLK_ENABLE;
                writel(val, regs + S3C64XX_SPI_CLK_CFG);
        }
}

#define XFER_DMAADDR_INVALID DMA_BIT_MASK(32)

static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd,
                                                struct spi_message *msg)
{
        struct device *dev = &sdd->pdev->dev;
        struct spi_transfer *xfer;

        if (msg->is_dma_mapped)
                return 0;

        /* First mark all xfer unmapped */
        list_for_each_entry(xfer, &msg->transfers, transfer_list) {
                xfer->rx_dma = XFER_DMAADDR_INVALID;
                xfer->tx_dma = XFER_DMAADDR_INVALID;
        }

        /* Map until end or first fail */
        list_for_each_entry(xfer, &msg->transfers, transfer_list) {

                if (xfer->len <= ((FIFO_LVL_MASK(sdd) >> 1) + 1))
                        continue;

                if (xfer->tx_buf != NULL) {
                        xfer->tx_dma = dma_map_single(dev,
                                        (void *)xfer->tx_buf, xfer->len,
                                        DMA_TO_DEVICE);
                        if (dma_mapping_error(dev, xfer->tx_dma)) {
                                dev_err(dev, "dma_map_single Tx failed\n");
                                xfer->tx_dma = XFER_DMAADDR_INVALID;
                                return -ENOMEM;
                        }
                }

                if (xfer->rx_buf != NULL) {
                        xfer->rx_dma = dma_map_single(dev, xfer->rx_buf,
                                                xfer->len, DMA_FROM_DEVICE);
                        if (dma_mapping_error(dev, xfer->rx_dma)) {
                                dev_err(dev, "dma_map_single Rx failed\n");
                                dma_unmap_single(dev, xfer->tx_dma,
                                                xfer->len, DMA_TO_DEVICE);
                                xfer->tx_dma = XFER_DMAADDR_INVALID;
                                xfer->rx_dma = XFER_DMAADDR_INVALID;
                                return -ENOMEM;
                        }
                }
        }

        return 0;
}

static void s3c64xx_spi_unmap_mssg(struct s3c64xx_spi_driver_data *sdd,
                                                struct spi_message *msg)
{
        struct device *dev = &sdd->pdev->dev;
        struct spi_transfer *xfer;

        if (msg->is_dma_mapped)
                return;

        list_for_each_entry(xfer, &msg->transfers, transfer_list) {

                if (xfer->len <= ((FIFO_LVL_MASK(sdd) >> 1) + 1))
                        continue;

                if (xfer->rx_buf != NULL
                                && xfer->rx_dma != XFER_DMAADDR_INVALID)
                        dma_unmap_single(dev, xfer->rx_dma,
                                                xfer->len, DMA_FROM_DEVICE);

                if (xfer->tx_buf != NULL
                                && xfer->tx_dma != XFER_DMAADDR_INVALID)
                        dma_unmap_single(dev, xfer->tx_dma,
                                                xfer->len, DMA_TO_DEVICE);
        }
}

static int s3c64xx_spi_transfer_one_message(struct spi_master *master,
                                            struct spi_message *msg)
{
        struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);
        struct spi_device *spi = msg->spi;
        struct s3c64xx_spi_csinfo *cs = spi->controller_data;
        struct spi_transfer *xfer;
        int status = 0, cs_toggle = 0;
        u32 speed;
        u8 bpw;

        /* If Master's(controller) state differs from that needed by Slave */
        if (sdd->cur_speed != spi->max_speed_hz
                        || sdd->cur_mode != spi->mode
                        || sdd->cur_bpw != spi->bits_per_word) {
                sdd->cur_bpw = spi->bits_per_word;
                sdd->cur_speed = spi->max_speed_hz;
                sdd->cur_mode = spi->mode;
                s3c64xx_spi_config(sdd);
        }

        /* Map all the transfers if needed */
        if (s3c64xx_spi_map_mssg(sdd, msg)) {
                dev_err(&spi->dev,
                        "Xfer: Unable to map message buffers!\n");
                status = -ENOMEM;
                goto out;
        }

        /* Configure feedback delay */
        writel(cs->fb_delay & 0x3, sdd->regs + S3C64XX_SPI_FB_CLK);

        list_for_each_entry(xfer, &msg->transfers, transfer_list) {

                unsigned long flags;
                int use_dma;

                INIT_COMPLETION(sdd->xfer_completion);

                /* Only BPW and Speed may change across transfers */
                bpw = xfer->bits_per_word;
                speed = xfer->speed_hz ? : spi->max_speed_hz;

                if (xfer->len % (bpw / 8)) {
                        dev_err(&spi->dev,
                                "Xfer length(%u) not a multiple of word size(%u)\n",
                                xfer->len, bpw / 8);
                        status = -EIO;
                        goto out;
                }

                if (bpw != sdd->cur_bpw || speed != sdd->cur_speed) {
                        sdd->cur_bpw = bpw;
                        sdd->cur_speed = speed;
                        s3c64xx_spi_config(sdd);
                }

                /* Polling method for xfers not bigger than FIFO capacity */
                if (xfer->len <= ((FIFO_LVL_MASK(sdd) >> 1) + 1))
                        use_dma = 0;
                else
                        use_dma = 1;

                spin_lock_irqsave(&sdd->lock, flags);

                /* Pending only which is to be done */
                sdd->state &= ~RXBUSY;
                sdd->state &= ~TXBUSY;

                enable_datapath(sdd, spi, xfer, use_dma);

                /* Slave Select */
                enable_cs(sdd, spi);

                /* Start the signals */
                writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);

                spin_unlock_irqrestore(&sdd->lock, flags);

                status = wait_for_xfer(sdd, xfer, use_dma);

                /* Quiese the signals */
                writel(S3C64XX_SPI_SLAVE_SIG_INACT,
                       sdd->regs + S3C64XX_SPI_SLAVE_SEL);

                if (status) {
                        dev_err(&spi->dev, "I/O Error: rx-%d tx-%d res:rx-%c tx-%c len-%d\n",
                                xfer->rx_buf ? 1 : 0, xfer->tx_buf ? 1 : 0,
                                (sdd->state & RXBUSY) ? 'f' : 'p',
                                (sdd->state & TXBUSY) ? 'f' : 'p',
                                xfer->len);

                        if (use_dma) {
                                if (xfer->tx_buf != NULL
                                                && (sdd->state & TXBUSY))
                                        sdd->ops->stop(sdd->tx_dma.ch);
                                if (xfer->rx_buf != NULL
                                                && (sdd->state & RXBUSY))
                                        sdd->ops->stop(sdd->rx_dma.ch);
                        }

                        goto out;
                }

                if (xfer->delay_usecs)
                        udelay(xfer->delay_usecs);

                if (xfer->cs_change) {
                        /* Hint that the next mssg is gonna be
                           for the same device */
                        if (list_is_last(&xfer->transfer_list,
                                                &msg->transfers))
                                cs_toggle = 1;
                }

                msg->actual_length += xfer->len;

                flush_fifo(sdd);
        }

out:
        if (!cs_toggle || status)
                disable_cs(sdd, spi);
        else
                sdd->tgl_spi = spi;

        s3c64xx_spi_unmap_mssg(sdd, msg);

        msg->status = status;

        spi_finalize_current_message(master);

        return 0;
}

static int s3c64xx_spi_prepare_transfer(struct spi_master *spi)
{
        struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi);

        /* Acquire DMA channels */
        while (!acquire_dma(sdd))
                usleep_range(10000, 11000);

        pm_runtime_get_sync(&sdd->pdev->dev);

        return 0;
}

static int s3c64xx_spi_unprepare_transfer(struct spi_master *spi)
{
        struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi);

        /* Free DMA channels */
        sdd->ops->release(sdd->rx_dma.ch, &s3c64xx_spi_dma_client);
        sdd->ops->release(sdd->tx_dma.ch, &s3c64xx_spi_dma_client);

        pm_runtime_put(&sdd->pdev->dev);

        return 0;
}

static struct s3c64xx_spi_csinfo *s3c64xx_get_slave_ctrldata(
                                struct s3c64xx_spi_driver_data *sdd,
                                struct spi_device *spi)
{
        struct s3c64xx_spi_csinfo *cs;
        struct device_node *slave_np, *data_np = NULL;
        u32 fb_delay = 0;

        slave_np = spi->dev.of_node;
        if (!slave_np) {
                dev_err(&spi->dev, "device node not found\n");
                return ERR_PTR(-EINVAL);
        }

        data_np = of_get_child_by_name(slave_np, "controller-data");
        if (!data_np) {
                dev_err(&spi->dev, "child node 'controller-data' not found\n");
                return ERR_PTR(-EINVAL);
        }

        cs = kzalloc(sizeof(*cs), GFP_KERNEL);
        if (!cs) {
                dev_err(&spi->dev, "could not allocate memory for controller data\n");
                of_node_put(data_np);
                return ERR_PTR(-ENOMEM);
        }

        cs->line = of_get_named_gpio(data_np, "cs-gpio", 0);
        if (!gpio_is_valid(cs->line)) {
                dev_err(&spi->dev, "chip select gpio is not specified or invalid\n");
                kfree(cs);
                of_node_put(data_np);
                return ERR_PTR(-EINVAL);
        }

        of_property_read_u32(data_np, "samsung,spi-feedback-delay", &fb_delay);
        cs->fb_delay = fb_delay;
        of_node_put(data_np);
        return cs;
}

/*
 * Here we only check the validity of requested configuration
 * and save the configuration in a local data-structure.
 * The controller is actually configured only just before we
 * get a message to transfer.
 */
static int s3c64xx_spi_setup(struct spi_device *spi)
{
        struct s3c64xx_spi_csinfo *cs = spi->controller_data;
        struct s3c64xx_spi_driver_data *sdd;
        struct s3c64xx_spi_info *sci;
        struct spi_message *msg;
        unsigned long flags;
        int err;

        sdd = spi_master_get_devdata(spi->master);
        if (!cs && spi->dev.of_node) {
                cs = s3c64xx_get_slave_ctrldata(sdd, spi);
                spi->controller_data = cs;
        }

        if (IS_ERR_OR_NULL(cs)) {
                dev_err(&spi->dev, "No CS for SPI(%d)\n", spi->chip_select);
                return -ENODEV;
        }

        if (!spi_get_ctldata(spi)) {
                err = gpio_request_one(cs->line, GPIOF_OUT_INIT_HIGH,
                                       dev_name(&spi->dev));
                if (err) {
                        dev_err(&spi->dev,
                                "Failed to get /CS gpio [%d]: %d\n",
                                cs->line, err);
                        goto err_gpio_req;
                }
                spi_set_ctldata(spi, cs);
        }

        sci = sdd->cntrlr_info;

        spin_lock_irqsave(&sdd->lock, flags);

        list_for_each_entry(msg, &sdd->queue, queue) {
                /* Is some mssg is already queued for this device */
                if (msg->spi == spi) {
                        dev_err(&spi->dev,
                                "setup: attempt while mssg in queue!\n");
                        spin_unlock_irqrestore(&sdd->lock, flags);
                        err = -EBUSY;
                        goto err_msgq;
                }
        }

        spin_unlock_irqrestore(&sdd->lock, flags);

        if (spi->bits_per_word != 8
                        && spi->bits_per_word != 16
                        && spi->bits_per_word != 32) {
                dev_err(&spi->dev, "setup: %dbits/wrd not supported!\n",
                                                        spi->bits_per_word);
                err = -EINVAL;
                goto setup_exit;
        }

        pm_runtime_get_sync(&sdd->pdev->dev);

        /* Check if we can provide the requested rate */
        if (!sdd->port_conf->clk_from_cmu) {
                u32 psr, speed;

                /* Max possible */
                speed = clk_get_rate(sdd->src_clk) / 2 / (0 + 1);

                if (spi->max_speed_hz > speed)
                        spi->max_speed_hz = speed;

                psr = clk_get_rate(sdd->src_clk) / 2 / spi->max_speed_hz - 1;
                psr &= S3C64XX_SPI_PSR_MASK;
                if (psr == S3C64XX_SPI_PSR_MASK)
                        psr--;

                speed = clk_get_rate(sdd->src_clk) / 2 / (psr + 1);
                if (spi->max_speed_hz < speed) {
                        if (psr+1 < S3C64XX_SPI_PSR_MASK) {
                                psr++;
                        } else {
                                err = -EINVAL;
                                goto setup_exit;
                        }
                }

                speed = clk_get_rate(sdd->src_clk) / 2 / (psr + 1);
                if (spi->max_speed_hz >= speed) {
                        spi->max_speed_hz = speed;
                } else {
                        dev_err(&spi->dev, "Can't set %dHz transfer speed\n",
                                spi->max_speed_hz);
                        err = -EINVAL;
                        goto setup_exit;
                }
        }

        pm_runtime_put(&sdd->pdev->dev);
        disable_cs(sdd, spi);
        return 0;

setup_exit:
        /* setup() returns with device de-selected */
        disable_cs(sdd, spi);

err_msgq:
        gpio_free(cs->line);
        spi_set_ctldata(spi, NULL);

err_gpio_req:
        if (spi->dev.of_node)
                kfree(cs);

        return err;
}

static void s3c64xx_spi_cleanup(struct spi_device *spi)
{
        struct s3c64xx_spi_csinfo *cs = spi_get_ctldata(spi);

        if (cs) {
                gpio_free(cs->line);
                if (spi->dev.of_node)
                        kfree(cs);
        }
        spi_set_ctldata(spi, NULL);
}

static irqreturn_t s3c64xx_spi_irq(int irq, void *data)
{
        struct s3c64xx_spi_driver_data *sdd = data;
        struct spi_master *spi = sdd->master;
        unsigned int val, clr = 0;

        val = readl(sdd->regs + S3C64XX_SPI_STATUS);

        if (val & S3C64XX_SPI_ST_RX_OVERRUN_ERR) {
                clr = S3C64XX_SPI_PND_RX_OVERRUN_CLR;
                dev_err(&spi->dev, "RX overrun\n");
        }
        if (val & S3C64XX_SPI_ST_RX_UNDERRUN_ERR) {
                clr |= S3C64XX_SPI_PND_RX_UNDERRUN_CLR;
                dev_err(&spi->dev, "RX underrun\n");
        }
        if (val & S3C64XX_SPI_ST_TX_OVERRUN_ERR) {
                clr |= S3C64XX_SPI_PND_TX_OVERRUN_CLR;
                dev_err(&spi->dev, "TX overrun\n");
        }
        if (val & S3C64XX_SPI_ST_TX_UNDERRUN_ERR) {
                clr |= S3C64XX_SPI_PND_TX_UNDERRUN_CLR;
                dev_err(&spi->dev, "TX underrun\n");
        }

        /* Clear the pending irq by setting and then clearing it */
        writel(clr, sdd->regs + S3C64XX_SPI_PENDING_CLR);
        writel(0, sdd->regs + S3C64XX_SPI_PENDING_CLR);

        return IRQ_HANDLED;
}

static void s3c64xx_spi_hwinit(struct s3c64xx_spi_driver_data *sdd, int channel)
{
        struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
        void __iomem *regs = sdd->regs;
        unsigned int val;

        sdd->cur_speed = 0;

        writel(S3C64XX_SPI_SLAVE_SIG_INACT, sdd->regs + S3C64XX_SPI_SLAVE_SEL);

        /* Disable Interrupts - we use Polling if not DMA mode */
        writel(0, regs + S3C64XX_SPI_INT_EN);

        if (!sdd->port_conf->clk_from_cmu)
                writel(sci->src_clk_nr << S3C64XX_SPI_CLKSEL_SRCSHFT,
                                regs + S3C64XX_SPI_CLK_CFG);
        writel(0, regs + S3C64XX_SPI_MODE_CFG);
        writel(0, regs + S3C64XX_SPI_PACKET_CNT);

        /* Clear any irq pending bits, should set and clear the bits */
        val = S3C64XX_SPI_PND_RX_OVERRUN_CLR |
                S3C64XX_SPI_PND_RX_UNDERRUN_CLR |
                S3C64XX_SPI_PND_TX_OVERRUN_CLR |
                S3C64XX_SPI_PND_TX_UNDERRUN_CLR;
        writel(val, regs + S3C64XX_SPI_PENDING_CLR);
        writel(0, regs + S3C64XX_SPI_PENDING_CLR);

        writel(0, regs + S3C64XX_SPI_SWAP_CFG);

        val = readl(regs + S3C64XX_SPI_MODE_CFG);
        val &= ~S3C64XX_SPI_MODE_4BURST;
        val &= ~(S3C64XX_SPI_MAX_TRAILCNT << S3C64XX_SPI_TRAILCNT_OFF);
        val |= (S3C64XX_SPI_TRAILCNT << S3C64XX_SPI_TRAILCNT_OFF);
        writel(val, regs + S3C64XX_SPI_MODE_CFG);

        flush_fifo(sdd);
}

#ifdef CONFIG_OF
static int s3c64xx_spi_parse_dt_gpio(struct s3c64xx_spi_driver_data *sdd)
{
        struct device *dev = &sdd->pdev->dev;
        int idx, gpio, ret;

        /* find gpios for mosi, miso and clock lines */
        for (idx = 0; idx < 3; idx++) {
                gpio = of_get_gpio(dev->of_node, idx);
                if (!gpio_is_valid(gpio)) {
                        dev_err(dev, "invalid gpio[%d]: %d\n", idx, gpio);
                        goto free_gpio;
                }
                sdd->gpios[idx] = gpio;
                ret = gpio_request(gpio, "spi-bus");
                if (ret) {
                        dev_err(dev, "gpio [%d] request failed: %d\n",
                                gpio, ret);
                        goto free_gpio;
                }
        }
        return 0;

free_gpio:
        while (--idx >= 0)
                gpio_free(sdd->gpios[idx]);
        return -EINVAL;
}

static void s3c64xx_spi_dt_gpio_free(struct s3c64xx_spi_driver_data *sdd)
{
        unsigned int idx;
        for (idx = 0; idx < 3; idx++)
                gpio_free(sdd->gpios[idx]);
}

static struct s3c64xx_spi_info *s3c64xx_spi_parse_dt(struct device *dev)
{
        struct s3c64xx_spi_info *sci;
        u32 temp;

        sci = devm_kzalloc(dev, sizeof(*sci), GFP_KERNEL);
        if (!sci) {
                dev_err(dev, "memory allocation for spi_info failed\n");
                return ERR_PTR(-ENOMEM);
        }

        if (of_property_read_u32(dev->of_node, "samsung,spi-src-clk", &temp)) {
                dev_warn(dev, "spi bus clock parent not specified, using clock at index 0 as parent\n");
                sci->src_clk_nr = 0;
        } else {
                sci->src_clk_nr = temp;
        }

        if (of_property_read_u32(dev->of_node, "num-cs", &temp)) {
                dev_warn(dev, "number of chip select lines not specified, assuming 1 chip select line\n");
                sci->num_cs = 1;
        } else {
                sci->num_cs = temp;
        }

        return sci;
}
#else
static struct s3c64xx_spi_info *s3c64xx_spi_parse_dt(struct device *dev)
{
        return dev->platform_data;
}

static int s3c64xx_spi_parse_dt_gpio(struct s3c64xx_spi_driver_data *sdd)
{
        return -EINVAL;
}

static void s3c64xx_spi_dt_gpio_free(struct s3c64xx_spi_driver_data *sdd)
{
}
#endif

static const struct of_device_id s3c64xx_spi_dt_match[];

static inline struct s3c64xx_spi_port_config *s3c64xx_spi_get_port_config(
                                                struct platform_device *pdev)
{
#ifdef CONFIG_OF
        if (pdev->dev.of_node) {
                const struct of_device_id *match;
                match = of_match_node(s3c64xx_spi_dt_match, pdev->dev.of_node);
                return (struct s3c64xx_spi_port_config *)match->data;
        }
#endif
        return (struct s3c64xx_spi_port_config *)
                         platform_get_device_id(pdev)->driver_data;
}

static int s3c64xx_spi_probe(struct platform_device *pdev)
{
        struct resource *mem_res;
        struct resource *res;
        struct s3c64xx_spi_driver_data *sdd;
        struct s3c64xx_spi_info *sci = pdev->dev.platform_data;
        struct spi_master *master;
        int ret, irq;
        char clk_name[16];

        if (!sci && pdev->dev.of_node) {
                sci = s3c64xx_spi_parse_dt(&pdev->dev);
                if (IS_ERR(sci))
                        return PTR_ERR(sci);
        }

        if (!sci) {
                dev_err(&pdev->dev, "platform_data missing!\n");
                return -ENODEV;
        }

        mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (mem_res == NULL) {
                dev_err(&pdev->dev, "Unable to get SPI MEM resource\n");
                return -ENXIO;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                dev_warn(&pdev->dev, "Failed to get IRQ: %d\n", irq);
                return irq;
        }

        master = spi_alloc_master(&pdev->dev,
                                sizeof(struct s3c64xx_spi_driver_data));
        if (master == NULL) {
                dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
                return -ENOMEM;
        }

        platform_set_drvdata(pdev, master);

        sdd = spi_master_get_devdata(master);
        sdd->port_conf = s3c64xx_spi_get_port_config(pdev);
        sdd->master = master;
        sdd->cntrlr_info = sci;
        sdd->pdev = pdev;
        sdd->sfr_start = mem_res->start;
        if (pdev->dev.of_node) {
                ret = of_alias_get_id(pdev->dev.of_node, "spi");
                if (ret < 0) {
                        dev_err(&pdev->dev, "failed to get alias id, errno %d\n",
                                ret);
                        goto err0;
                }
                sdd->port_id = ret;
        } else {
                sdd->port_id = pdev->id;
        }

        sdd->cur_bpw = 8;

        if (!sdd->pdev->dev.of_node) {
                res = platform_get_resource(pdev, IORESOURCE_DMA,  0);
                if (!res) {
                        dev_err(&pdev->dev, "Unable to get SPI tx dma "
                                        "resource\n");
                        return -ENXIO;
                }
                sdd->tx_dma.dmach = res->start;

                res = platform_get_resource(pdev, IORESOURCE_DMA,  1);
                if (!res) {
                        dev_err(&pdev->dev, "Unable to get SPI rx dma "
                                        "resource\n");
                        return -ENXIO;
                }
                sdd->rx_dma.dmach = res->start;
        }

        sdd->tx_dma.direction = DMA_MEM_TO_DEV;
        sdd->rx_dma.direction = DMA_DEV_TO_MEM;

        master->dev.of_node = pdev->dev.of_node;
        master->bus_num = sdd->port_id;
        master->setup = s3c64xx_spi_setup;
        master->cleanup = s3c64xx_spi_cleanup;
        master->prepare_transfer_hardware = s3c64xx_spi_prepare_transfer;
        master->transfer_one_message = s3c64xx_spi_transfer_one_message;
        master->unprepare_transfer_hardware = s3c64xx_spi_unprepare_transfer;
        master->num_chipselect = sci->num_cs;
        master->dma_alignment = 8;
        /* the spi->mode bits understood by this driver: */
        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;

        sdd->regs = devm_ioremap_resource(&pdev->dev, mem_res);
        if (IS_ERR(sdd->regs)) {
                ret = PTR_ERR(sdd->regs);
                goto err0;
        }

        if (!sci->cfg_gpio && pdev->dev.of_node) {
                if (s3c64xx_spi_parse_dt_gpio(sdd))
                        return -EBUSY;
        } else if (sci->cfg_gpio == NULL || sci->cfg_gpio()) {
                dev_err(&pdev->dev, "Unable to config gpio\n");
                ret = -EBUSY;
                goto err0;
        }

        /* Setup clocks */
        sdd->clk = devm_clk_get(&pdev->dev, "spi");
        if (IS_ERR(sdd->clk)) {
                dev_err(&pdev->dev, "Unable to acquire clock 'spi'\n");
                ret = PTR_ERR(sdd->clk);
                goto err1;
        }

        if (clk_prepare_enable(sdd->clk)) {
                dev_err(&pdev->dev, "Couldn't enable clock 'spi'\n");
                ret = -EBUSY;
                goto err1;
        }

        sprintf(clk_name, "spi_busclk%d", sci->src_clk_nr);
        sdd->src_clk = devm_clk_get(&pdev->dev, clk_name);
        if (IS_ERR(sdd->src_clk)) {
                dev_err(&pdev->dev,
                        "Unable to acquire clock '%s'\n", clk_name);
                ret = PTR_ERR(sdd->src_clk);
                goto err2;
        }

        if (clk_prepare_enable(sdd->src_clk)) {
                dev_err(&pdev->dev, "Couldn't enable clock '%s'\n", clk_name);
                ret = -EBUSY;
                goto err2;
        }

        /* Setup Deufult Mode */
        s3c64xx_spi_hwinit(sdd, sdd->port_id);

        spin_lock_init(&sdd->lock);
        init_completion(&sdd->xfer_completion);
        INIT_LIST_HEAD(&sdd->queue);

        ret = devm_request_irq(&pdev->dev, irq, s3c64xx_spi_irq, 0,
                                "spi-s3c64xx", sdd);
        if (ret != 0) {
                dev_err(&pdev->dev, "Failed to request IRQ %d: %d\n",
                        irq, ret);
                goto err3;
        }

        writel(S3C64XX_SPI_INT_RX_OVERRUN_EN | S3C64XX_SPI_INT_RX_UNDERRUN_EN |
               S3C64XX_SPI_INT_TX_OVERRUN_EN | S3C64XX_SPI_INT_TX_UNDERRUN_EN,
               sdd->regs + S3C64XX_SPI_INT_EN);

        if (spi_register_master(master)) {
                dev_err(&pdev->dev, "cannot register SPI master\n");
                ret = -EBUSY;
                goto err3;
        }

        dev_dbg(&pdev->dev, "Samsung SoC SPI Driver loaded for Bus SPI-%d with %d Slaves attached\n",
                                        sdd->port_id, master->num_chipselect);
        dev_dbg(&pdev->dev, "\tIOmem=[0x%x-0x%x]\tDMA=[Rx-%d, Tx-%d]\n",
                                        mem_res->end, mem_res->start,
                                        sdd->rx_dma.dmach, sdd->tx_dma.dmach);

        pm_runtime_enable(&pdev->dev);

        return 0;

err3:
        clk_disable_unprepare(sdd->src_clk);
err2:
        clk_disable_unprepare(sdd->clk);
err1:
        if (!sdd->cntrlr_info->cfg_gpio && pdev->dev.of_node)
                s3c64xx_spi_dt_gpio_free(sdd);
err0:
        platform_set_drvdata(pdev, NULL);
        spi_master_put(master);

        return ret;
}

static int s3c64xx_spi_remove(struct platform_device *pdev)
{
        struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
        struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);

        pm_runtime_disable(&pdev->dev);

        spi_unregister_master(master);

        writel(0, sdd->regs + S3C64XX_SPI_INT_EN);

        clk_disable_unprepare(sdd->src_clk);

        clk_disable_unprepare(sdd->clk);

        if (!sdd->cntrlr_info->cfg_gpio && pdev->dev.of_node)
                s3c64xx_spi_dt_gpio_free(sdd);

        platform_set_drvdata(pdev, NULL);
        spi_master_put(master);

        return 0;
}

#ifdef CONFIG_PM
static int s3c64xx_spi_suspend(struct device *dev)
{
        struct spi_master *master = dev_get_drvdata(dev);
        struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);

        spi_master_suspend(master);

        /* Disable the clock */
        clk_disable_unprepare(sdd->src_clk);
        clk_disable_unprepare(sdd->clk);

        if (!sdd->cntrlr_info->cfg_gpio && dev->of_node)
                s3c64xx_spi_dt_gpio_free(sdd);

        sdd->cur_speed = 0; /* Output Clock is stopped */

        return 0;
}

static int s3c64xx_spi_resume(struct device *dev)
{
        struct spi_master *master = dev_get_drvdata(dev);
        struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);
        struct s3c64xx_spi_info *sci = sdd->cntrlr_info;

        if (!sci->cfg_gpio && dev->of_node)
                s3c64xx_spi_parse_dt_gpio(sdd);
        else
                sci->cfg_gpio();

        /* Enable the clock */
        clk_prepare_enable(sdd->src_clk);
        clk_prepare_enable(sdd->clk);

        s3c64xx_spi_hwinit(sdd, sdd->port_id);

        spi_master_resume(master);

        return 0;
}
#endif /* CONFIG_PM */

#ifdef CONFIG_PM_RUNTIME
static int s3c64xx_spi_runtime_suspend(struct device *dev)
{
        struct spi_master *master = dev_get_drvdata(dev);
        struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);

        clk_disable_unprepare(sdd->clk);
        clk_disable_unprepare(sdd->src_clk);

        return 0;
}

static int s3c64xx_spi_runtime_resume(struct device *dev)
{
        struct spi_master *master = dev_get_drvdata(dev);
        struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);

        clk_prepare_enable(sdd->src_clk);
        clk_prepare_enable(sdd->clk);

        return 0;
}
#endif /* CONFIG_PM_RUNTIME */

static const struct dev_pm_ops s3c64xx_spi_pm = {
        SET_SYSTEM_SLEEP_PM_OPS(s3c64xx_spi_suspend, s3c64xx_spi_resume)
        SET_RUNTIME_PM_OPS(s3c64xx_spi_runtime_suspend,
                           s3c64xx_spi_runtime_resume, NULL)
};

static struct s3c64xx_spi_port_config s3c2443_spi_port_config = {
        .fifo_lvl_mask  = { 0x7f },
        .rx_lvl_offset  = 13,
        .tx_st_done     = 21,
        .high_speed     = true,
};

static struct s3c64xx_spi_port_config s3c6410_spi_port_config = {
        .fifo_lvl_mask  = { 0x7f, 0x7F },
        .rx_lvl_offset  = 13,
        .tx_st_done     = 21,
};

static struct s3c64xx_spi_port_config s5p64x0_spi_port_config = {
        .fifo_lvl_mask  = { 0x1ff, 0x7F },
        .rx_lvl_offset  = 15,
        .tx_st_done     = 25,
};

static struct s3c64xx_spi_port_config s5pc100_spi_port_config = {
        .fifo_lvl_mask  = { 0x7f, 0x7F },
        .rx_lvl_offset  = 13,
        .tx_st_done     = 21,
        .high_speed     = true,
};

static struct s3c64xx_spi_port_config s5pv210_spi_port_config = {
        .fifo_lvl_mask  = { 0x1ff, 0x7F },
        .rx_lvl_offset  = 15,
        .tx_st_done     = 25,
        .high_speed     = true,
};

static struct s3c64xx_spi_port_config exynos4_spi_port_config = {
        .fifo_lvl_mask  = { 0x1ff, 0x7F, 0x7F },
        .rx_lvl_offset  = 15,
        .tx_st_done     = 25,
        .high_speed     = true,
        .clk_from_cmu   = true,
};

static struct platform_device_id s3c64xx_spi_driver_ids[] = {
        {
                .name           = "s3c2443-spi",
                .driver_data    = (kernel_ulong_t)&s3c2443_spi_port_config,
        }, {
                .name           = "s3c6410-spi",
                .driver_data    = (kernel_ulong_t)&s3c6410_spi_port_config,
        }, {
                .name           = "s5p64x0-spi",
                .driver_data    = (kernel_ulong_t)&s5p64x0_spi_port_config,
        }, {
                .name           = "s5pc100-spi",
                .driver_data    = (kernel_ulong_t)&s5pc100_spi_port_config,
        }, {
                .name           = "s5pv210-spi",
                .driver_data    = (kernel_ulong_t)&s5pv210_spi_port_config,
        }, {
                .name           = "exynos4210-spi",
                .driver_data    = (kernel_ulong_t)&exynos4_spi_port_config,
        },
        { },
};

#ifdef CONFIG_OF
static const struct of_device_id s3c64xx_spi_dt_match[] = {
        { .compatible = "samsung,exynos4210-spi",
                        .data = (void *)&exynos4_spi_port_config,
        },
        { },
};
MODULE_DEVICE_TABLE(of, s3c64xx_spi_dt_match);
#endif /* CONFIG_OF */

static struct platform_driver s3c64xx_spi_driver = {
        .driver = {
                .name   = "s3c64xx-spi",
                .owner = THIS_MODULE,
                .pm = &s3c64xx_spi_pm,
                .of_match_table = of_match_ptr(s3c64xx_spi_dt_match),
        },
        .remove = s3c64xx_spi_remove,
        .id_table = s3c64xx_spi_driver_ids,
};
MODULE_ALIAS("platform:s3c64xx-spi");

static int __init s3c64xx_spi_init(void)
{
        return platform_driver_probe(&s3c64xx_spi_driver, s3c64xx_spi_probe);
}
subsys_initcall(s3c64xx_spi_init);

static void __exit s3c64xx_spi_exit(void)
{
        platform_driver_unregister(&s3c64xx_spi_driver);
}
module_exit(s3c64xx_spi_exit);

MODULE_AUTHOR("Jaswinder Singh <jassi.brar@samsung.com>");
MODULE_DESCRIPTION("S3C64XX SPI Controller Driver");
MODULE_LICENSE("GPL");