// SPDX-License-Identifier: GPL-2.0+
//
// Copyright (c) 2009 Samsung Electronics Co., Ltd.
//      Jaswinder Singh <jassi.brar@samsung.com>

#include <linux/bitops.h>
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_data/spi-s3c64xx.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/types.h>

#define MAX_SPI_PORTS           12
#define S3C64XX_SPI_QUIRK_CS_AUTO       (1 << 1)
#define AUTOSUSPEND_TIMEOUT     2000

/* 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_CS_REG              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_RX_RDY_LVL             GENMASK(16, 11)
#define S3C64XX_SPI_MODE_RX_RDY_LVL_SHIFT       11
#define S3C64XX_SPI_MODE_SELF_LOOPBACK          (1<<3)
#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_CS_NSC_CNT_2                (2<<4)
#define S3C64XX_SPI_CS_AUTO                     (1<<1)
#define S3C64XX_SPI_CS_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_FIFO_RDY_V2           GENMASK(23, 15)
#define S3C64XX_SPI_ST_TX_FIFO_RDY_V2           GENMASK(14, 6)
#define S3C64XX_SPI_ST_TX_FIFO_LVL_SHIFT        6
#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_PACKET_CNT_MASK             GENMASK(15, 0)

#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, sdd)     (((v) & (sdd)->tx_fifomask) >>          \
                                 __ffs((sdd)->tx_fifomask))
#define RX_FIFO_LVL(v, sdd)     (((v) & (sdd)->rx_fifomask) >>          \
                                 __ffs((sdd)->rx_fifomask))
#define FIFO_DEPTH(i) ((FIFO_LVL_MASK(i) >> 1) + 1)

#define S3C64XX_SPI_MAX_TRAILCNT        0x3ff
#define S3C64XX_SPI_TRAILCNT_OFF        19

#define S3C64XX_SPI_POLLING_SIZE        32

#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
#define is_polling(x)   (x->cntrlr_info->polling)

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

struct s3c64xx_spi_dma_data {
        struct dma_chan *ch;
        dma_cookie_t cookie;
        enum dma_transfer_direction direction;
};

/**
 * struct s3c64xx_spi_port_config - SPI Controller hardware info
 * @fifo_lvl_mask: [DEPRECATED] use @{rx, tx}_fifomask instead.
 * @rx_lvl_offset: [DEPRECATED] use @{rx,tx}_fifomask instead.
 * @fifo_depth: depth of the FIFOs. Used by compatibles where all the instances
 *              of the IP define the same FIFO depth. It has higher precedence
 *              than the FIFO depth specified via DT.
 * @rx_fifomask: SPI_STATUS.RX_FIFO_LVL mask. Shifted mask defining the field's
 *               length and position.
 * @tx_fifomask: SPI_STATUS.TX_FIFO_LVL mask. Shifted mask defining the field's
 *               length and position.
 * @tx_st_done: Bit offset of TX_DONE bit in SPI_STATUS regiter.
 * @clk_div: Internal clock divider
 * @quirks: Bitmask of known quirks
 * @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.
 * @clk_ioclk: True if clock is present on this device
 * @has_loopback: True if loopback mode can be supported
 * @use_32bit_io: True if the SoC allows only 32-bit register accesses.
 *
 * 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;
        unsigned int fifo_depth;
        u32     rx_fifomask;
        u32     tx_fifomask;
        int     tx_st_done;
        int     quirks;
        int     clk_div;
        bool    high_speed;
        bool    clk_from_cmu;
        bool    clk_ioclk;
        bool    has_loopback;
        bool    use_32bit_io;
};

/**
 * 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.
 * @ioclk: Pointer to the i/o clock between host and target
 * @pdev: Pointer to device's platform device data
 * @host: Pointer to the SPI Protocol host.
 * @cntrlr_info: Platform specific data for the controller this driver manages.
 * @lock: Controller specific lock.
 * @state: Set of FLAGS to indicate status.
 * @sfr_start: BUS address of SPI controller regs.
 * @regs: Pointer to ioremap'ed controller registers.
 * @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: Current clock speed
 * @rx_dma: Local receive DMA data (e.g. chan and direction)
 * @tx_dma: Local transmit DMA data (e.g. chan and direction)
 * @port_conf: Local SPI port configuration data
 * @port_id: [DEPRECATED] use @{rx,tx}_fifomask instead.
 * @fifo_depth: depth of the FIFO.
 * @rx_fifomask: SPI_STATUS.RX_FIFO_LVL mask. Shifted mask defining the field's
 *               length and position.
 * @tx_fifomask: SPI_STATUS.TX_FIFO_LVL mask. Shifted mask defining the field's
 *               length and position.
 */
struct s3c64xx_spi_driver_data {
        void __iomem                    *regs;
        struct clk                      *clk;
        struct clk                      *src_clk;
        struct clk                      *ioclk;
        struct platform_device          *pdev;
        struct spi_controller           *host;
        struct s3c64xx_spi_info         *cntrlr_info;
        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;
        const struct s3c64xx_spi_port_config    *port_conf;
        unsigned int                    port_id;
        unsigned int                    fifo_depth;
        u32                             rx_fifomask;
        u32                             tx_fifomask;
};

static void s3c64xx_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 int s3c64xx_prepare_dma(struct s3c64xx_spi_dma_data *dma,
                               struct sg_table *sgt)
{
        struct s3c64xx_spi_driver_data *sdd;
        struct dma_slave_config config;
        struct dma_async_tx_descriptor *desc;
        int ret;

        memset(&config, 0, sizeof(config));

        if (dma->direction == DMA_DEV_TO_MEM) {
                sdd = container_of((void *)dma,
                        struct s3c64xx_spi_driver_data, rx_dma);
                config.src_addr = sdd->sfr_start + S3C64XX_SPI_RX_DATA;
                config.src_addr_width = sdd->cur_bpw / 8;
                config.src_maxburst = 1;
        } else {
                sdd = container_of((void *)dma,
                        struct s3c64xx_spi_driver_data, tx_dma);
                config.dst_addr = sdd->sfr_start + S3C64XX_SPI_TX_DATA;
                config.dst_addr_width = sdd->cur_bpw / 8;
                config.dst_maxburst = 1;
        }
        config.direction = dma->direction;
        ret = dmaengine_slave_config(dma->ch, &config);
        if (ret)
                return ret;

        desc = dmaengine_prep_slave_sg(dma->ch, sgt->sgl, sgt->nents,
                                       dma->direction, DMA_PREP_INTERRUPT);
        if (!desc) {
                dev_err(&sdd->pdev->dev, "unable to prepare %s scatterlist",
                        dma->direction == DMA_DEV_TO_MEM ? "rx" : "tx");
                return -ENOMEM;
        }

        desc->callback = s3c64xx_spi_dmacb;
        desc->callback_param = dma;

        dma->cookie = dmaengine_submit(desc);
        ret = dma_submit_error(dma->cookie);
        if (ret) {
                dev_err(&sdd->pdev->dev, "DMA submission failed");
                return ret;
        }

        dma_async_issue_pending(dma->ch);
        return 0;
}

static void s3c64xx_spi_set_cs(struct spi_device *spi, bool enable)
{
        struct s3c64xx_spi_driver_data *sdd =
                                        spi_controller_get_devdata(spi->controller);

        if (sdd->cntrlr_info->no_cs)
                return;

        if (enable) {
                if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO)) {
                        writel(0, sdd->regs + S3C64XX_SPI_CS_REG);
                } else {
                        u32 ssel = readl(sdd->regs + S3C64XX_SPI_CS_REG);

                        ssel |= (S3C64XX_SPI_CS_AUTO |
                                                S3C64XX_SPI_CS_NSC_CNT_2);
                        writel(ssel, sdd->regs + S3C64XX_SPI_CS_REG);
                }
        } else {
                if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO))
                        writel(S3C64XX_SPI_CS_SIG_INACT,
                               sdd->regs + S3C64XX_SPI_CS_REG);
        }
}

static int s3c64xx_spi_prepare_transfer(struct spi_controller *spi)
{
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(spi);

        if (is_polling(sdd))
                return 0;

        /* Requests DMA channels */
        sdd->rx_dma.ch = dma_request_chan(&sdd->pdev->dev, "rx");
        if (IS_ERR(sdd->rx_dma.ch)) {
                dev_err(&sdd->pdev->dev, "Failed to get RX DMA channel\n");
                sdd->rx_dma.ch = NULL;
                return 0;
        }

        sdd->tx_dma.ch = dma_request_chan(&sdd->pdev->dev, "tx");
        if (IS_ERR(sdd->tx_dma.ch)) {
                dev_err(&sdd->pdev->dev, "Failed to get TX DMA channel\n");
                dma_release_channel(sdd->rx_dma.ch);
                sdd->tx_dma.ch = NULL;
                sdd->rx_dma.ch = NULL;
                return 0;
        }

        spi->dma_rx = sdd->rx_dma.ch;
        spi->dma_tx = sdd->tx_dma.ch;

        return 0;
}

static int s3c64xx_spi_unprepare_transfer(struct spi_controller *spi)
{
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(spi);

        if (is_polling(sdd))
                return 0;

        /* Releases DMA channels if they are allocated */
        if (sdd->rx_dma.ch && sdd->tx_dma.ch) {
                dma_release_channel(sdd->rx_dma.ch);
                dma_release_channel(sdd->tx_dma.ch);
                sdd->rx_dma.ch = NULL;
                sdd->tx_dma.ch = NULL;
        }

        return 0;
}

static bool s3c64xx_spi_can_dma(struct spi_controller *host,
                                struct spi_device *spi,
                                struct spi_transfer *xfer)
{
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);

        if (sdd->rx_dma.ch && sdd->tx_dma.ch)
                return xfer->len >= sdd->fifo_depth;

        return false;
}

static void s3c64xx_iowrite8_32_rep(volatile void __iomem *addr,
                                    const void *buffer, unsigned int count)
{
        if (count) {
                const u8 *buf = buffer;

                do {
                        __raw_writel(*buf++, addr);
                } while (--count);
        }
}

static void s3c64xx_iowrite16_32_rep(volatile void __iomem *addr,
                                     const void *buffer, unsigned int count)
{
        if (count) {
                const u16 *buf = buffer;

                do {
                        __raw_writel(*buf++, addr);
                } while (--count);
        }
}

static void s3c64xx_iowrite_rep(const struct s3c64xx_spi_driver_data *sdd,
                                struct spi_transfer *xfer)
{
        void __iomem *addr = sdd->regs + S3C64XX_SPI_TX_DATA;
        const void *buf = xfer->tx_buf;
        unsigned int len = xfer->len;

        switch (sdd->cur_bpw) {
        case 32:
                iowrite32_rep(addr, buf, len / 4);
                break;
        case 16:
                if (sdd->port_conf->use_32bit_io)
                        s3c64xx_iowrite16_32_rep(addr, buf, len / 2);
                else
                        iowrite16_rep(addr, buf, len / 2);
                break;
        default:
                if (sdd->port_conf->use_32bit_io)
                        s3c64xx_iowrite8_32_rep(addr, buf, len);
                else
                        iowrite8_rep(addr, buf, len);
                break;
        }
}

static int s3c64xx_enable_datapath(struct s3c64xx_spi_driver_data *sdd,
                                    struct spi_transfer *xfer, int dma_mode)
{
        void __iomem *regs = sdd->regs;
        u32 modecfg, chcfg;
        int ret = 0;

        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;
                        ret = s3c64xx_prepare_dma(&sdd->tx_dma, &xfer->tx_sg);
                } else {
                        s3c64xx_iowrite_rep(sdd, xfer);
                }
        }

        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);
                        ret = s3c64xx_prepare_dma(&sdd->rx_dma, &xfer->rx_sg);
                }
        }

        if (ret)
                return ret;

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

        return 0;
}

static u32 s3c64xx_spi_wait_for_timeout(struct s3c64xx_spi_driver_data *sdd,
                                        int timeout_ms)
{
        void __iomem *regs = sdd->regs;
        unsigned long val = 1;
        u32 status;
        u32 max_fifo = sdd->fifo_depth;

        if (timeout_ms)
                val = msecs_to_loops(timeout_ms);

        do {
                status = readl(regs + S3C64XX_SPI_STATUS);
        } while (RX_FIFO_LVL(status, sdd) < max_fifo && --val);

        /* return the actual received data length */
        return RX_FIFO_LVL(status, sdd);
}

static int s3c64xx_wait_for_dma(struct s3c64xx_spi_driver_data *sdd,
                                struct spi_transfer *xfer)
{
        void __iomem *regs = sdd->regs;
        unsigned long val;
        u32 status;
        int ms;

        /* millisecs to xfer 'len' bytes @ 'cur_speed' */
        ms = xfer->len * 8 * 1000 / sdd->cur_speed;
        ms += 30;               /* some tolerance */
        ms = max(ms, 100);      /* minimum timeout */

        val = msecs_to_jiffies(ms) + 10;
        val = wait_for_completion_timeout(&sdd->xfer_completion, val);

        /*
         * If the previous xfer was completed within timeout, then
         * proceed further else return -ETIMEDOUT.
         * 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 (val && !xfer->rx_buf) {
                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 timed out while checking rx/tx status return error */
        if (!val)
                return -ETIMEDOUT;

        return 0;
}

static int s3c64xx_wait_for_pio(struct s3c64xx_spi_driver_data *sdd,
                                struct spi_transfer *xfer, bool use_irq)
{
        void __iomem *regs = sdd->regs;
        unsigned long val;
        u32 status;
        int loops;
        u32 cpy_len;
        u8 *buf;
        int ms;
        unsigned long time_us;

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

        /* sleep during signal transfer time */
        status = readl(regs + S3C64XX_SPI_STATUS);
        if (RX_FIFO_LVL(status, sdd) < xfer->len)
                usleep_range(time_us / 2, time_us);

        if (use_irq) {
                val = msecs_to_jiffies(ms);
                if (!wait_for_completion_timeout(&sdd->xfer_completion, val))
                        return -ETIMEDOUT;
        }

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

        /*
         * If the receive length is bigger than the controller fifo
         * size, calculate the loops and read the fifo as many times.
         * loops = length / max fifo size (calculated by using the
         * fifo mask).
         * For any size less than the fifo size the below code is
         * executed atleast once.
         */
        loops = xfer->len / sdd->fifo_depth;
        buf = xfer->rx_buf;
        do {
                /* wait for data to be received in the fifo */
                cpy_len = s3c64xx_spi_wait_for_timeout(sdd,
                                                       (loops ? ms : 0));

                switch (sdd->cur_bpw) {
                case 32:
                        ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
                                     buf, cpy_len / 4);
                        break;
                case 16:
                        ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
                                     buf, cpy_len / 2);
                        break;
                default:
                        ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
                                    buf, cpy_len);
                        break;
                }

                buf = buf + cpy_len;
        } while (loops--);
        sdd->state &= ~RXBUSY;

        return 0;
}

static int s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
{
        void __iomem *regs = sdd->regs;
        int ret;
        u32 val;
        int div = sdd->port_conf->clk_div;

        /* Disable Clock */
        if (!sdd->port_conf->clk_from_cmu) {
                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;
        }

        if ((sdd->cur_mode & SPI_LOOP) && sdd->port_conf->has_loopback)
                val |= S3C64XX_SPI_MODE_SELF_LOOPBACK;
        else
                val &= ~S3C64XX_SPI_MODE_SELF_LOOPBACK;

        writel(val, regs + S3C64XX_SPI_MODE_CFG);

        if (sdd->port_conf->clk_from_cmu) {
                ret = clk_set_rate(sdd->src_clk, sdd->cur_speed * div);
                if (ret)
                        return ret;
                sdd->cur_speed = clk_get_rate(sdd->src_clk) / div;
        } 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 / div - 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);
        }

        return 0;
}

#define XFER_DMAADDR_INVALID DMA_BIT_MASK(32)

static int s3c64xx_spi_prepare_message(struct spi_controller *host,
                                       struct spi_message *msg)
{
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
        struct spi_device *spi = msg->spi;
        struct s3c64xx_spi_csinfo *cs = spi->controller_data;

        /* Configure feedback delay */
        if (!cs)
                /* No delay if not defined */
                writel(0, sdd->regs + S3C64XX_SPI_FB_CLK);
        else
                writel(cs->fb_delay & 0x3, sdd->regs + S3C64XX_SPI_FB_CLK);

        return 0;
}

static size_t s3c64xx_spi_max_transfer_size(struct spi_device *spi)
{
        struct spi_controller *ctlr = spi->controller;

        return ctlr->can_dma ? S3C64XX_SPI_PACKET_CNT_MASK : SIZE_MAX;
}

static int s3c64xx_spi_transfer_one(struct spi_controller *host,
                                    struct spi_device *spi,
                                    struct spi_transfer *xfer)
{
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
        const unsigned int fifo_len = sdd->fifo_depth;
        const void *tx_buf = NULL;
        void *rx_buf = NULL;
        int target_len = 0, origin_len = 0;
        int use_dma = 0;
        bool use_irq = false;
        int status;
        u32 speed;
        u8 bpw;
        unsigned long flags;
        u32 rdy_lv;
        u32 val;

        reinit_completion(&sdd->xfer_completion);

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

        if (bpw != sdd->cur_bpw || speed != sdd->cur_speed) {
                sdd->cur_bpw = bpw;
                sdd->cur_speed = speed;
                sdd->cur_mode = spi->mode;
                status = s3c64xx_spi_config(sdd);
                if (status)
                        return status;
        }

        if (!is_polling(sdd) && xfer->len >= fifo_len &&
            sdd->rx_dma.ch && sdd->tx_dma.ch) {
                use_dma = 1;
        } else if (xfer->len >= fifo_len) {
                tx_buf = xfer->tx_buf;
                rx_buf = xfer->rx_buf;
                origin_len = xfer->len;
                target_len = xfer->len;
                xfer->len = fifo_len - 1;
        }

        do {
                /* transfer size is greater than 32, change to IRQ mode */
                if (!use_dma && xfer->len > S3C64XX_SPI_POLLING_SIZE)
                        use_irq = true;

                if (use_irq) {
                        reinit_completion(&sdd->xfer_completion);

                        rdy_lv = xfer->len;
                        /* Setup RDY_FIFO trigger Level
                         * RDY_LVL =
                         * fifo_lvl up to 64 byte -> N bytes
                         *               128 byte -> RDY_LVL * 2 bytes
                         *               256 byte -> RDY_LVL * 4 bytes
                         */
                        if (fifo_len == 128)
                                rdy_lv /= 2;
                        else if (fifo_len == 256)
                                rdy_lv /= 4;

                        val = readl(sdd->regs + S3C64XX_SPI_MODE_CFG);
                        val &= ~S3C64XX_SPI_MODE_RX_RDY_LVL;
                        val |= (rdy_lv << S3C64XX_SPI_MODE_RX_RDY_LVL_SHIFT);
                        writel(val, sdd->regs + S3C64XX_SPI_MODE_CFG);

                        /* Enable FIFO_RDY_EN IRQ */
                        val = readl(sdd->regs + S3C64XX_SPI_INT_EN);
                        writel((val | S3C64XX_SPI_INT_RX_FIFORDY_EN),
                                        sdd->regs + S3C64XX_SPI_INT_EN);

                }

                spin_lock_irqsave(&sdd->lock, flags);

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

                /* Start the signals */
                s3c64xx_spi_set_cs(spi, true);

                status = s3c64xx_enable_datapath(sdd, xfer, use_dma);

                spin_unlock_irqrestore(&sdd->lock, flags);

                if (status) {
                        dev_err(&spi->dev, "failed to enable data path for transfer: %d\n", status);
                        break;
                }

                if (use_dma)
                        status = s3c64xx_wait_for_dma(sdd, xfer);
                else
                        status = s3c64xx_wait_for_pio(sdd, xfer, use_irq);

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

                        if (use_dma) {
                                struct dma_tx_state s;

                                if (xfer->tx_buf && (sdd->state & TXBUSY)) {
                                        dmaengine_pause(sdd->tx_dma.ch);
                                        dmaengine_tx_status(sdd->tx_dma.ch, sdd->tx_dma.cookie, &s);
                                        dmaengine_terminate_all(sdd->tx_dma.ch);
                                        dev_err(&spi->dev, "TX residue: %d\n", s.residue);

                                }
                                if (xfer->rx_buf && (sdd->state & RXBUSY)) {
                                        dmaengine_pause(sdd->rx_dma.ch);
                                        dmaengine_tx_status(sdd->rx_dma.ch, sdd->rx_dma.cookie, &s);
                                        dmaengine_terminate_all(sdd->rx_dma.ch);
                                        dev_err(&spi->dev, "RX residue: %d\n", s.residue);
                                }
                        }
                } else {
                        s3c64xx_flush_fifo(sdd);
                }
                if (target_len > 0) {
                        target_len -= xfer->len;

                        if (xfer->tx_buf)
                                xfer->tx_buf += xfer->len;

                        if (xfer->rx_buf)
                                xfer->rx_buf += xfer->len;

                        if (target_len >= fifo_len)
                                xfer->len = fifo_len - 1;
                        else
                                xfer->len = target_len;
                }
        } while (target_len > 0);

        if (origin_len) {
                /* Restore original xfer buffers and length */
                xfer->tx_buf = tx_buf;
                xfer->rx_buf = rx_buf;
                xfer->len = origin_len;
        }

        return status;
}

static struct s3c64xx_spi_csinfo *s3c64xx_get_target_ctrldata(
                                struct spi_device *spi)
{
        struct s3c64xx_spi_csinfo *cs;
        struct device_node *target_np;
        u32 fb_delay = 0;

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

        cs = kzalloc_obj(*cs);
        if (!cs)
                return ERR_PTR(-ENOMEM);

        struct device_node *data_np __free(device_node) =
                        of_get_child_by_name(target_np, "controller-data");
        if (!data_np) {
                dev_info(&spi->dev, "feedback delay set to default (0)\n");
                return cs;
        }

        of_property_read_u32(data_np, "samsung,spi-feedback-delay", &fb_delay);
        cs->fb_delay = fb_delay;
        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;
        int err;
        int div;

        sdd = spi_controller_get_devdata(spi->controller);
        if (spi->dev.of_node) {
                cs = s3c64xx_get_target_ctrldata(spi);
                spi->controller_data = cs;
        }

        /* NULL is fine, we just avoid using the FB delay (=0) */
        if (IS_ERR(cs)) {
                dev_err(&spi->dev, "No CS for SPI(%d)\n", spi_get_chipselect(spi, 0));
                return -ENODEV;
        }

        if (!spi_get_ctldata(spi))
                spi_set_ctldata(spi, cs);

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

        div = sdd->port_conf->clk_div;

        /* 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) / div / (0 + 1);

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

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

                speed = clk_get_rate(sdd->src_clk) / div / (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) / div / (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_autosuspend(&sdd->pdev->dev);
        s3c64xx_spi_set_cs(spi, false);

        return 0;

setup_exit:
        pm_runtime_put_autosuspend(&sdd->pdev->dev);
        /* setup() returns with device de-selected */
        s3c64xx_spi_set_cs(spi, false);

        spi_set_ctldata(spi, NULL);

        /* This was dynamically allocated on the DT path */
        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);

        /* This was dynamically allocated on the DT path */
        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_controller *spi = sdd->host;
        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");
        }

        if (val & S3C64XX_SPI_ST_RX_FIFORDY) {
                complete(&sdd->xfer_completion);
                /* No pending clear irq, turn-off INT_EN_RX_FIFO_RDY */
                val = readl(sdd->regs + S3C64XX_SPI_INT_EN);
                writel((val & ~S3C64XX_SPI_INT_RX_FIFORDY_EN),
                                sdd->regs + S3C64XX_SPI_INT_EN);
        }

        /* 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)
{
        struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
        void __iomem *regs = sdd->regs;
        unsigned int val;

        sdd->cur_speed = 0;

        if (sci->no_cs)
                writel(0, sdd->regs + S3C64XX_SPI_CS_REG);
        else if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO))
                writel(S3C64XX_SPI_CS_SIG_INACT, sdd->regs + S3C64XX_SPI_CS_REG);

        /* 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);
        writel(val, regs + S3C64XX_SPI_MODE_CFG);

        s3c64xx_flush_fifo(sdd);
}

#ifdef CONFIG_OF
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)
                return ERR_PTR(-ENOMEM);

        if (of_property_read_u32(dev->of_node, "samsung,spi-src-clk", &temp)) {
                dev_dbg(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_dbg(dev, "number of chip select lines not specified, assuming 1 chip select line\n");
                sci->num_cs = 1;
        } else {
                sci->num_cs = temp;
        }

        sci->no_cs = of_property_read_bool(dev->of_node, "no-cs-readback");
        sci->polling = !of_property_present(dev->of_node, "dmas");

        return sci;
}
#else
static struct s3c64xx_spi_info *s3c64xx_spi_parse_dt(struct device *dev)
{
        return dev_get_platdata(dev);
}
#endif

static inline const struct s3c64xx_spi_port_config *s3c64xx_spi_get_port_config(
                                                struct platform_device *pdev)
{
#ifdef CONFIG_OF
        if (pdev->dev.of_node)
                return of_device_get_match_data(&pdev->dev);
#endif
        return (const struct s3c64xx_spi_port_config *)platform_get_device_id(pdev)->driver_data;
}

static int s3c64xx_spi_set_port_id(struct platform_device *pdev,
                                   struct s3c64xx_spi_driver_data *sdd)
{
        const struct s3c64xx_spi_port_config *port_conf = sdd->port_conf;
        int ret;

        if (port_conf->rx_fifomask && port_conf->tx_fifomask)
                return 0;

        if (pdev->dev.of_node) {
                ret = of_alias_get_id(pdev->dev.of_node, "spi");
                if (ret < 0)
                        return dev_err_probe(&pdev->dev, ret,
                                             "Failed to get alias id\n");
                sdd->port_id = ret;
        } else {
                if (pdev->id < 0)
                        return dev_err_probe(&pdev->dev, -EINVAL,
                                             "Negative platform ID is not allowed\n");
                sdd->port_id = pdev->id;
        }

        return 0;
}

static void s3c64xx_spi_set_fifomask(struct s3c64xx_spi_driver_data *sdd)
{
        const struct s3c64xx_spi_port_config *port_conf = sdd->port_conf;

        if (port_conf->rx_fifomask)
                sdd->rx_fifomask = port_conf->rx_fifomask;
        else
                sdd->rx_fifomask = FIFO_LVL_MASK(sdd) <<
                        port_conf->rx_lvl_offset;

        if (port_conf->tx_fifomask)
                sdd->tx_fifomask = port_conf->tx_fifomask;
        else
                sdd->tx_fifomask = FIFO_LVL_MASK(sdd) <<
                        S3C64XX_SPI_ST_TX_FIFO_LVL_SHIFT;
}

static int s3c64xx_spi_probe(struct platform_device *pdev)
{
        struct resource *mem_res;
        struct s3c64xx_spi_driver_data *sdd;
        struct s3c64xx_spi_info *sci = dev_get_platdata(&pdev->dev);
        struct spi_controller *host;
        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)
                return dev_err_probe(&pdev->dev, -ENODEV,
                                     "Platform_data missing!\n");

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        host = devm_spi_alloc_host(&pdev->dev, sizeof(*sdd));
        if (!host)
                return -ENOMEM;

        platform_set_drvdata(pdev, host);

        sdd = spi_controller_get_devdata(host);
        sdd->port_conf = s3c64xx_spi_get_port_config(pdev);
        sdd->host = host;
        sdd->cntrlr_info = sci;
        sdd->pdev = pdev;

        ret = s3c64xx_spi_set_port_id(pdev, sdd);
        if (ret)
                return ret;

        if (sdd->port_conf->fifo_depth)
                sdd->fifo_depth = sdd->port_conf->fifo_depth;
        else if (of_property_read_u32(pdev->dev.of_node, "fifo-depth",
                                      &sdd->fifo_depth))
                sdd->fifo_depth = FIFO_DEPTH(sdd);

        s3c64xx_spi_set_fifomask(sdd);

        sdd->cur_bpw = 8;

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

        host->bus_num = -1;
        host->setup = s3c64xx_spi_setup;
        host->cleanup = s3c64xx_spi_cleanup;
        host->prepare_transfer_hardware = s3c64xx_spi_prepare_transfer;
        host->unprepare_transfer_hardware = s3c64xx_spi_unprepare_transfer;
        host->prepare_message = s3c64xx_spi_prepare_message;
        host->transfer_one = s3c64xx_spi_transfer_one;
        host->max_transfer_size = s3c64xx_spi_max_transfer_size;
        host->num_chipselect = sci->num_cs;
        host->use_gpio_descriptors = true;
        host->dma_alignment = 8;
        host->bits_per_word_mask = SPI_BPW_MASK(32) | SPI_BPW_MASK(16) |
                                   SPI_BPW_MASK(8);
        /* the spi->mode bits understood by this driver: */
        host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
        if (sdd->port_conf->has_loopback)
                host->mode_bits |= SPI_LOOP;
        host->auto_runtime_pm = true;
        if (!is_polling(sdd))
                host->can_dma = s3c64xx_spi_can_dma;

        sdd->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &mem_res);
        if (IS_ERR(sdd->regs))
                return PTR_ERR(sdd->regs);
        sdd->sfr_start = mem_res->start;

        if (sci->cfg_gpio && sci->cfg_gpio())
                return dev_err_probe(&pdev->dev, -EBUSY,
                                     "Unable to config gpio\n");

        /* Setup clocks */
        sdd->clk = devm_clk_get_enabled(&pdev->dev, "spi");
        if (IS_ERR(sdd->clk))
                return dev_err_probe(&pdev->dev, PTR_ERR(sdd->clk),
                                     "Unable to acquire clock 'spi'\n");

        sprintf(clk_name, "spi_busclk%d", sci->src_clk_nr);
        sdd->src_clk = devm_clk_get_enabled(&pdev->dev, clk_name);
        if (IS_ERR(sdd->src_clk))
                return dev_err_probe(&pdev->dev, PTR_ERR(sdd->src_clk),
                                     "Unable to acquire clock '%s'\n",
                                     clk_name);

        if (sdd->port_conf->clk_ioclk) {
                sdd->ioclk = devm_clk_get_enabled(&pdev->dev, "spi_ioclk");
                if (IS_ERR(sdd->ioclk))
                        return dev_err_probe(&pdev->dev, PTR_ERR(sdd->ioclk),
                                             "Unable to acquire 'ioclk'\n");
        }

        pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
        pm_runtime_use_autosuspend(&pdev->dev);
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);
        pm_runtime_get_sync(&pdev->dev);

        /* Setup Default Mode */
        s3c64xx_spi_hwinit(sdd);

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

        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 err_pm_put;
        }

        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);

        ret = spi_register_controller(host);
        if (ret != 0) {
                dev_err(&pdev->dev, "cannot register SPI host: %d\n", ret);
                goto err_pm_put;
        }

        dev_dbg(&pdev->dev, "Samsung SoC SPI Driver loaded for Bus SPI-%d with %d Targets attached\n",
                host->bus_num, host->num_chipselect);
        dev_dbg(&pdev->dev, "\tIOmem=[%pR]\tFIFO %dbytes\n",
                mem_res, sdd->fifo_depth);

        pm_runtime_put_autosuspend(&pdev->dev);

        return 0;

err_pm_put:
        pm_runtime_put_noidle(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        pm_runtime_set_suspended(&pdev->dev);

        return ret;
}

static void s3c64xx_spi_remove(struct platform_device *pdev)
{
        struct spi_controller *host = platform_get_drvdata(pdev);
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);

        pm_runtime_get_sync(&pdev->dev);

        spi_unregister_controller(host);

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

        pm_runtime_put_noidle(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        pm_runtime_set_suspended(&pdev->dev);
}

#ifdef CONFIG_PM_SLEEP
static int s3c64xx_spi_suspend(struct device *dev)
{
        struct spi_controller *host = dev_get_drvdata(dev);
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
        int ret;

        ret = spi_controller_suspend(host);
        if (ret)
                return ret;

        ret = pm_runtime_force_suspend(dev);
        if (ret < 0)
                return ret;

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

        return 0;
}

static int s3c64xx_spi_resume(struct device *dev)
{
        struct spi_controller *host = dev_get_drvdata(dev);
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
        struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
        int ret;

        if (sci->cfg_gpio)
                sci->cfg_gpio();

        ret = pm_runtime_force_resume(dev);
        if (ret < 0)
                return ret;

        return spi_controller_resume(host);
}
#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_PM
static int s3c64xx_spi_runtime_suspend(struct device *dev)
{
        struct spi_controller *host = dev_get_drvdata(dev);
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);

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

        return 0;
}

static int s3c64xx_spi_runtime_resume(struct device *dev)
{
        struct spi_controller *host = dev_get_drvdata(dev);
        struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
        int ret;

        if (sdd->port_conf->clk_ioclk) {
                ret = clk_prepare_enable(sdd->ioclk);
                if (ret != 0)
                        return ret;
        }

        ret = clk_prepare_enable(sdd->src_clk);
        if (ret != 0)
                goto err_disable_ioclk;

        ret = clk_prepare_enable(sdd->clk);
        if (ret != 0)
                goto err_disable_src_clk;

        s3c64xx_spi_hwinit(sdd);

        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);

        return 0;

err_disable_src_clk:
        clk_disable_unprepare(sdd->src_clk);
err_disable_ioclk:
        clk_disable_unprepare(sdd->ioclk);

        return ret;
}
#endif /* CONFIG_PM */

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 const struct s3c64xx_spi_port_config s3c6410_spi_port_config = {
        /* fifo_lvl_mask is deprecated. Use {rx, tx}_fifomask instead. */
        .fifo_lvl_mask  = { 0x7f, 0x7F },
        /* rx_lvl_offset is deprecated. Use {rx, tx}_fifomask instead. */
        .rx_lvl_offset  = 13,
        .tx_st_done     = 21,
        .clk_div        = 2,
};

static const struct s3c64xx_spi_port_config s5pv210_spi_port_config = {
        /* fifo_lvl_mask is deprecated. Use {rx, tx}_fifomask instead. */
        .fifo_lvl_mask  = { 0x1ff, 0x7F },
        /* rx_lvl_offset is deprecated. Use {rx, tx}_fifomask instead. */
        .rx_lvl_offset  = 15,
        .tx_st_done     = 25,
        .clk_div        = 2,
        .high_speed     = true,
};

static const struct s3c64xx_spi_port_config exynos4_spi_port_config = {
        /* fifo_lvl_mask is deprecated. Use {rx, tx}_fifomask instead. */
        .fifo_lvl_mask  = { 0x1ff, 0x7F, 0x7F },
        /* rx_lvl_offset is deprecated. Use {rx, tx}_fifomask instead. */
        .rx_lvl_offset  = 15,
        .tx_st_done     = 25,
        .clk_div        = 2,
        .high_speed     = true,
        .clk_from_cmu   = true,
        .quirks         = S3C64XX_SPI_QUIRK_CS_AUTO,
};

static const struct s3c64xx_spi_port_config exynos7_spi_port_config = {
        /* fifo_lvl_mask is deprecated. Use {rx, tx}_fifomask instead. */
        .fifo_lvl_mask  = { 0x1ff, 0x7F, 0x7F, 0x7F, 0x7F, 0x1ff},
        /* rx_lvl_offset is deprecated. Use {rx, tx}_fifomask instead. */
        .rx_lvl_offset  = 15,
        .tx_st_done     = 25,
        .clk_div        = 2,
        .high_speed     = true,
        .clk_from_cmu   = true,
        .quirks         = S3C64XX_SPI_QUIRK_CS_AUTO,
};

static const struct s3c64xx_spi_port_config exynos5433_spi_port_config = {
        /* fifo_lvl_mask is deprecated. Use {rx, tx}_fifomask instead. */
        .fifo_lvl_mask  = { 0x1ff, 0x7f, 0x7f, 0x7f, 0x7f, 0x1ff},
        /* rx_lvl_offset is deprecated. Use {rx, tx}_fifomask instead. */
        .rx_lvl_offset  = 15,
        .tx_st_done     = 25,
        .clk_div        = 2,
        .high_speed     = true,
        .clk_from_cmu   = true,
        .clk_ioclk      = true,
        .quirks         = S3C64XX_SPI_QUIRK_CS_AUTO,
};

static const struct s3c64xx_spi_port_config exynos850_spi_port_config = {
        .fifo_depth     = 64,
        .rx_fifomask    = S3C64XX_SPI_ST_RX_FIFO_RDY_V2,
        .tx_fifomask    = S3C64XX_SPI_ST_TX_FIFO_RDY_V2,
        .tx_st_done     = 25,
        .clk_div        = 4,
        .high_speed     = true,
        .clk_from_cmu   = true,
        .has_loopback   = true,
        .quirks         = S3C64XX_SPI_QUIRK_CS_AUTO,
};

static const struct s3c64xx_spi_port_config exynosautov9_spi_port_config = {
        /* fifo_lvl_mask is deprecated. Use {rx, tx}_fifomask instead. */
        .fifo_lvl_mask  = { 0x1ff, 0x1ff, 0x7f, 0x7f, 0x7f, 0x7f, 0x1ff, 0x7f,
                            0x7f, 0x7f, 0x7f, 0x7f},
        /* rx_lvl_offset is deprecated. Use {rx, tx}_fifomask instead. */
        .rx_lvl_offset  = 15,
        .tx_st_done     = 25,
        .clk_div        = 4,
        .high_speed     = true,
        .clk_from_cmu   = true,
        .clk_ioclk      = true,
        .has_loopback   = true,
        .quirks         = S3C64XX_SPI_QUIRK_CS_AUTO,
};

static const struct s3c64xx_spi_port_config fsd_spi_port_config = {
        /* fifo_lvl_mask is deprecated. Use {rx, tx}_fifomask instead. */
        .fifo_lvl_mask  = { 0x7f, 0x7f, 0x7f, 0x7f, 0x7f},
        /* rx_lvl_offset is deprecated. Use {rx, tx}_fifomask instead. */
        .rx_lvl_offset  = 15,
        .tx_st_done     = 25,
        .clk_div        = 2,
        .high_speed     = true,
        .clk_from_cmu   = true,
        .clk_ioclk      = false,
        .quirks         = S3C64XX_SPI_QUIRK_CS_AUTO,
};

static const struct s3c64xx_spi_port_config gs101_spi_port_config = {
        .fifo_depth     = 64,
        .rx_fifomask    = S3C64XX_SPI_ST_RX_FIFO_RDY_V2,
        .tx_fifomask    = S3C64XX_SPI_ST_TX_FIFO_RDY_V2,
        .tx_st_done     = 25,
        .clk_div        = 4,
        .high_speed     = true,
        .clk_from_cmu   = true,
        .has_loopback   = true,
        .use_32bit_io   = true,
        .quirks         = S3C64XX_SPI_QUIRK_CS_AUTO,
};

static const struct platform_device_id s3c64xx_spi_driver_ids[] = {
        {
                .name = "s3c6410-spi",
                .driver_data = (kernel_ulong_t)&s3c6410_spi_port_config,
        },
        { }
};
MODULE_DEVICE_TABLE(platform, s3c64xx_spi_driver_ids);

static const struct of_device_id s3c64xx_spi_dt_match[] = {
        { .compatible = "google,gs101-spi",
                        .data = &gs101_spi_port_config,
        },
        { .compatible = "samsung,s3c6410-spi",
                        .data = &s3c6410_spi_port_config,
        },
        { .compatible = "samsung,s5pv210-spi",
                        .data = &s5pv210_spi_port_config,
        },
        { .compatible = "samsung,exynos4210-spi",
                        .data = &exynos4_spi_port_config,
        },
        { .compatible = "samsung,exynos7-spi",
                        .data = &exynos7_spi_port_config,
        },
        { .compatible = "samsung,exynos5433-spi",
                        .data = &exynos5433_spi_port_config,
        },
        { .compatible = "samsung,exynos850-spi",
                        .data = &exynos850_spi_port_config,
        },
        { .compatible = "samsung,exynosautov9-spi",
                        .data = &exynosautov9_spi_port_config,
        },
        { .compatible = "tesla,fsd-spi",
                        .data = &fsd_spi_port_config,
        },
        { },
};
MODULE_DEVICE_TABLE(of, s3c64xx_spi_dt_match);

static struct platform_driver s3c64xx_spi_driver = {
        .driver = {
                .name   = "s3c64xx-spi",
                .pm = &s3c64xx_spi_pm,
                .of_match_table = of_match_ptr(s3c64xx_spi_dt_match),
        },
        .probe = s3c64xx_spi_probe,
        .remove = s3c64xx_spi_remove,
        .id_table = s3c64xx_spi_driver_ids,
};
MODULE_ALIAS("platform:s3c64xx-spi");

module_platform_driver(s3c64xx_spi_driver);

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