drivers/spi/spi-synquacer.c

// SPDX-License-Identifier: GPL-2.0
//
// Synquacer HSSPI controller driver
//
// Copyright (c) 2015-2018 Socionext Inc.
// Copyright (c) 2018-2019 Linaro Ltd.
//

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spinlock.h>
#include <linux/clk.h>

/* HSSPI register address definitions */
#define SYNQUACER_HSSPI_REG_MCTRL	0x00
#define SYNQUACER_HSSPI_REG_PCC0	0x04
#define SYNQUACER_HSSPI_REG_PCC(n)	(SYNQUACER_HSSPI_REG_PCC0 + (n) * 4)
#define SYNQUACER_HSSPI_REG_TXF		0x14
#define SYNQUACER_HSSPI_REG_TXE		0x18
#define SYNQUACER_HSSPI_REG_TXC		0x1C
#define SYNQUACER_HSSPI_REG_RXF		0x20
#define SYNQUACER_HSSPI_REG_RXE		0x24
#define SYNQUACER_HSSPI_REG_RXC		0x28
#define SYNQUACER_HSSPI_REG_FAULTF	0x2C
#define SYNQUACER_HSSPI_REG_FAULTC	0x30
#define SYNQUACER_HSSPI_REG_DMCFG	0x34
#define SYNQUACER_HSSPI_REG_DMSTART	0x38
#define SYNQUACER_HSSPI_REG_DMBCC	0x3C
#define SYNQUACER_HSSPI_REG_DMSTATUS	0x40
#define SYNQUACER_HSSPI_REG_FIFOCFG	0x4C
#define SYNQUACER_HSSPI_REG_TX_FIFO	0x50
#define SYNQUACER_HSSPI_REG_RX_FIFO	0x90
#define SYNQUACER_HSSPI_REG_MID		0xFC

/* HSSPI register bit definitions */
#define SYNQUACER_HSSPI_MCTRL_MEN			BIT(0)
#define SYNQUACER_HSSPI_MCTRL_COMMAND_SEQUENCE_EN	BIT(1)
#define SYNQUACER_HSSPI_MCTRL_CDSS			BIT(3)
#define SYNQUACER_HSSPI_MCTRL_MES			BIT(4)
#define SYNQUACER_HSSPI_MCTRL_SYNCON			BIT(5)

#define SYNQUACER_HSSPI_PCC_CPHA		BIT(0)
#define SYNQUACER_HSSPI_PCC_CPOL		BIT(1)
#define SYNQUACER_HSSPI_PCC_ACES		BIT(2)
#define SYNQUACER_HSSPI_PCC_RTM			BIT(3)
#define SYNQUACER_HSSPI_PCC_SSPOL		BIT(4)
#define SYNQUACER_HSSPI_PCC_SDIR		BIT(7)
#define SYNQUACER_HSSPI_PCC_SENDIAN		BIT(8)
#define SYNQUACER_HSSPI_PCC_SAFESYNC		BIT(16)
#define SYNQUACER_HSSPI_PCC_SS2CD_SHIFT		5U
#define SYNQUACER_HSSPI_PCC_CDRS_MASK		0x7f
#define SYNQUACER_HSSPI_PCC_CDRS_SHIFT		9U

#define SYNQUACER_HSSPI_TXF_FIFO_FULL		BIT(0)
#define SYNQUACER_HSSPI_TXF_FIFO_EMPTY		BIT(1)
#define SYNQUACER_HSSPI_TXF_SLAVE_RELEASED	BIT(6)

#define SYNQUACER_HSSPI_TXE_FIFO_FULL		BIT(0)
#define SYNQUACER_HSSPI_TXE_FIFO_EMPTY		BIT(1)
#define SYNQUACER_HSSPI_TXE_SLAVE_RELEASED	BIT(6)

#define SYNQUACER_HSSPI_RXF_FIFO_MORE_THAN_THRESHOLD		BIT(5)
#define SYNQUACER_HSSPI_RXF_SLAVE_RELEASED			BIT(6)

#define SYNQUACER_HSSPI_RXE_FIFO_MORE_THAN_THRESHOLD		BIT(5)
#define SYNQUACER_HSSPI_RXE_SLAVE_RELEASED			BIT(6)

#define SYNQUACER_HSSPI_DMCFG_SSDC		BIT(1)
#define SYNQUACER_HSSPI_DMCFG_MSTARTEN		BIT(2)

#define SYNQUACER_HSSPI_DMSTART_START		BIT(0)
#define SYNQUACER_HSSPI_DMSTOP_STOP		BIT(8)
#define SYNQUACER_HSSPI_DMPSEL_CS_MASK		0x3
#define SYNQUACER_HSSPI_DMPSEL_CS_SHIFT		16U
#define SYNQUACER_HSSPI_DMTRP_BUS_WIDTH_SHIFT	24U
#define SYNQUACER_HSSPI_DMTRP_DATA_MASK		0x3
#define SYNQUACER_HSSPI_DMTRP_DATA_SHIFT	26U
#define SYNQUACER_HSSPI_DMTRP_DATA_TXRX		0
#define SYNQUACER_HSSPI_DMTRP_DATA_RX		1
#define SYNQUACER_HSSPI_DMTRP_DATA_TX		2

#define SYNQUACER_HSSPI_DMSTATUS_RX_DATA_MASK	0x1f
#define SYNQUACER_HSSPI_DMSTATUS_RX_DATA_SHIFT	8U
#define SYNQUACER_HSSPI_DMSTATUS_TX_DATA_MASK	0x1f
#define SYNQUACER_HSSPI_DMSTATUS_TX_DATA_SHIFT	16U

#define SYNQUACER_HSSPI_FIFOCFG_RX_THRESHOLD_MASK	0xf
#define SYNQUACER_HSSPI_FIFOCFG_RX_THRESHOLD_SHIFT	0U
#define SYNQUACER_HSSPI_FIFOCFG_TX_THRESHOLD_MASK	0xf
#define SYNQUACER_HSSPI_FIFOCFG_TX_THRESHOLD_SHIFT	4U
#define SYNQUACER_HSSPI_FIFOCFG_FIFO_WIDTH_MASK		0x3
#define SYNQUACER_HSSPI_FIFOCFG_FIFO_WIDTH_SHIFT	8U
#define SYNQUACER_HSSPI_FIFOCFG_RX_FLUSH		BIT(11)
#define SYNQUACER_HSSPI_FIFOCFG_TX_FLUSH		BIT(12)

#define SYNQUACER_HSSPI_FIFO_DEPTH		16U
#define SYNQUACER_HSSPI_FIFO_TX_THRESHOLD	4U
#define SYNQUACER_HSSPI_FIFO_RX_THRESHOLD \
	(SYNQUACER_HSSPI_FIFO_DEPTH - SYNQUACER_HSSPI_FIFO_TX_THRESHOLD)

#define SYNQUACER_HSSPI_TRANSFER_MODE_TX	BIT(1)
#define SYNQUACER_HSSPI_TRANSFER_MODE_RX	BIT(2)
#define SYNQUACER_HSSPI_TRANSFER_TMOUT_MSEC	2000U
#define SYNQUACER_HSSPI_ENABLE_TMOUT_MSEC	1000U

#define SYNQUACER_HSSPI_CLOCK_SRC_IHCLK		0
#define SYNQUACER_HSSPI_CLOCK_SRC_IPCLK		1

#define SYNQUACER_HSSPI_NUM_CHIP_SELECT		4U
#define SYNQUACER_HSSPI_IRQ_NAME_MAX		32U

struct synquacer_spi {
	struct device *dev;
	struct completion transfer_done;
	unsigned int cs;
	unsigned int bpw;
	unsigned int mode;
	unsigned int speed;
	bool aces, rtm;
	void *rx_buf;
	const void *tx_buf;
	struct clk *clk;
	int clk_src_type;
	void __iomem *regs;
	u32 tx_words, rx_words;
	unsigned int bus_width;
	unsigned int transfer_mode;
	char rx_irq_name[SYNQUACER_HSSPI_IRQ_NAME_MAX];
	char tx_irq_name[SYNQUACER_HSSPI_IRQ_NAME_MAX];
};

static int read_fifo(struct synquacer_spi *sspi)
{
	u32 len = readl(sspi->regs + SYNQUACER_HSSPI_REG_DMSTATUS);

	len = (len >> SYNQUACER_HSSPI_DMSTATUS_RX_DATA_SHIFT) &
	       SYNQUACER_HSSPI_DMSTATUS_RX_DATA_MASK;
	len = min(len, sspi->rx_words);

	switch (sspi->bpw) {
	case 8: {
		u8 *buf = sspi->rx_buf;

		ioread8_rep(sspi->regs + SYNQUACER_HSSPI_REG_RX_FIFO,
			    buf, len);
		sspi->rx_buf = buf + len;
		break;
	}
	case 16: {
		u16 *buf = sspi->rx_buf;

		ioread16_rep(sspi->regs + SYNQUACER_HSSPI_REG_RX_FIFO,
			     buf, len);
		sspi->rx_buf = buf + len;
		break;
	}
	case 24:
		/* fallthrough, should use 32-bits access */
	case 32: {
		u32 *buf = sspi->rx_buf;

		ioread32_rep(sspi->regs + SYNQUACER_HSSPI_REG_RX_FIFO,
			     buf, len);
		sspi->rx_buf = buf + len;
		break;
	}
	default:
		return -EINVAL;
	}

	sspi->rx_words -= len;
	return 0;
}

static int write_fifo(struct synquacer_spi *sspi)
{
	u32 len = readl(sspi->regs + SYNQUACER_HSSPI_REG_DMSTATUS);

	len = (len >> SYNQUACER_HSSPI_DMSTATUS_TX_DATA_SHIFT) &
	       SYNQUACER_HSSPI_DMSTATUS_TX_DATA_MASK;
	len = min(SYNQUACER_HSSPI_FIFO_DEPTH - len,
		    sspi->tx_words);

	switch (sspi->bpw) {
	case 8: {
		const u8 *buf = sspi->tx_buf;

		iowrite8_rep(sspi->regs + SYNQUACER_HSSPI_REG_TX_FIFO,
			     buf, len);
		sspi->tx_buf = buf + len;
		break;
	}
	case 16: {
		const u16 *buf = sspi->tx_buf;

		iowrite16_rep(sspi->regs + SYNQUACER_HSSPI_REG_TX_FIFO,
			      buf, len);
		sspi->tx_buf = buf + len;
		break;
	}
	case 24:
		/* fallthrough, should use 32-bits access */
	case 32: {
		const u32 *buf = sspi->tx_buf;

		iowrite32_rep(sspi->regs + SYNQUACER_HSSPI_REG_TX_FIFO,
			      buf, len);
		sspi->tx_buf = buf + len;
		break;
	}
	default:
		return -EINVAL;
	}

	sspi->tx_words -= len;
	return 0;
}

static int synquacer_spi_config(struct spi_master *master,
				struct spi_device *spi,
				struct spi_transfer *xfer)
{
	struct synquacer_spi *sspi = spi_master_get_devdata(master);
	unsigned int speed, mode, bpw, cs, bus_width, transfer_mode;
	u32 rate, val, div;

	/* Full Duplex only on 1-bit wide bus */
	if (xfer->rx_buf && xfer->tx_buf &&
	    (xfer->rx_nbits != 1 || xfer->tx_nbits != 1)) {
		dev_err(sspi->dev,
			"RX and TX bus widths must be 1-bit for Full-Duplex!\n");
		return -EINVAL;
	}

	if (xfer->tx_buf) {
		bus_width = xfer->tx_nbits;
		transfer_mode = SYNQUACER_HSSPI_TRANSFER_MODE_TX;
	} else {
		bus_width = xfer->rx_nbits;
		transfer_mode = SYNQUACER_HSSPI_TRANSFER_MODE_RX;
	}

	mode = spi->mode;
	cs = spi->chip_select;
	speed = xfer->speed_hz;
	bpw = xfer->bits_per_word;

	/* return if nothing to change */
	if (speed == sspi->speed &&
		bus_width == sspi->bus_width && bpw == sspi->bpw &&
		mode == sspi->mode && cs == sspi->cs &&
		transfer_mode == sspi->transfer_mode) {
		return 0;
	}

	sspi->transfer_mode = transfer_mode;
	rate = master->max_speed_hz;

	div = DIV_ROUND_UP(rate, speed);
	if (div > 254) {
		dev_err(sspi->dev, "Requested rate too low (%u)\n",
			sspi->speed);
		return -EINVAL;
	}

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_PCC(cs));
	val &= ~SYNQUACER_HSSPI_PCC_SAFESYNC;
	if (bpw == 8 &&	(mode & (SPI_TX_DUAL | SPI_RX_DUAL)) && div < 3)
		val |= SYNQUACER_HSSPI_PCC_SAFESYNC;
	if (bpw == 8 &&	(mode & (SPI_TX_QUAD | SPI_RX_QUAD)) && div < 6)
		val |= SYNQUACER_HSSPI_PCC_SAFESYNC;
	if (bpw == 16 && (mode & (SPI_TX_QUAD | SPI_RX_QUAD)) && div < 3)
		val |= SYNQUACER_HSSPI_PCC_SAFESYNC;

	if (mode & SPI_CPHA)
		val |= SYNQUACER_HSSPI_PCC_CPHA;
	else
		val &= ~SYNQUACER_HSSPI_PCC_CPHA;

	if (mode & SPI_CPOL)
		val |= SYNQUACER_HSSPI_PCC_CPOL;
	else
		val &= ~SYNQUACER_HSSPI_PCC_CPOL;

	if (mode & SPI_CS_HIGH)
		val |= SYNQUACER_HSSPI_PCC_SSPOL;
	else
		val &= ~SYNQUACER_HSSPI_PCC_SSPOL;

	if (mode & SPI_LSB_FIRST)
		val |= SYNQUACER_HSSPI_PCC_SDIR;
	else
		val &= ~SYNQUACER_HSSPI_PCC_SDIR;

	if (sspi->aces)
		val |= SYNQUACER_HSSPI_PCC_ACES;
	else
		val &= ~SYNQUACER_HSSPI_PCC_ACES;

	if (sspi->rtm)
		val |= SYNQUACER_HSSPI_PCC_RTM;
	else
		val &= ~SYNQUACER_HSSPI_PCC_RTM;

	val |= (3 << SYNQUACER_HSSPI_PCC_SS2CD_SHIFT);
	val |= SYNQUACER_HSSPI_PCC_SENDIAN;

	val &= ~(SYNQUACER_HSSPI_PCC_CDRS_MASK <<
		 SYNQUACER_HSSPI_PCC_CDRS_SHIFT);
	val |= ((div >> 1) << SYNQUACER_HSSPI_PCC_CDRS_SHIFT);

	writel(val, sspi->regs + SYNQUACER_HSSPI_REG_PCC(cs));

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_FIFOCFG);
	val &= ~(SYNQUACER_HSSPI_FIFOCFG_FIFO_WIDTH_MASK <<
		 SYNQUACER_HSSPI_FIFOCFG_FIFO_WIDTH_SHIFT);
	val |= ((bpw / 8 - 1) << SYNQUACER_HSSPI_FIFOCFG_FIFO_WIDTH_SHIFT);
	writel(val, sspi->regs + SYNQUACER_HSSPI_REG_FIFOCFG);

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);
	val &= ~(SYNQUACER_HSSPI_DMTRP_DATA_MASK <<
		 SYNQUACER_HSSPI_DMTRP_DATA_SHIFT);

	if (xfer->rx_buf)
		val |= (SYNQUACER_HSSPI_DMTRP_DATA_RX <<
			SYNQUACER_HSSPI_DMTRP_DATA_SHIFT);
	else
		val |= (SYNQUACER_HSSPI_DMTRP_DATA_TX <<
			SYNQUACER_HSSPI_DMTRP_DATA_SHIFT);

	val &= ~(3 << SYNQUACER_HSSPI_DMTRP_BUS_WIDTH_SHIFT);
	val |= ((bus_width >> 1) << SYNQUACER_HSSPI_DMTRP_BUS_WIDTH_SHIFT);
	writel(val, sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);

	sspi->bpw = bpw;
	sspi->mode = mode;
	sspi->speed = speed;
	sspi->cs = spi->chip_select;
	sspi->bus_width = bus_width;

	return 0;
}

static int synquacer_spi_transfer_one(struct spi_master *master,
				      struct spi_device *spi,
				      struct spi_transfer *xfer)
{
	struct synquacer_spi *sspi = spi_master_get_devdata(master);
	int ret;
	int status = 0;
	u32 words;
	u8 bpw;
	u32 val;

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);
	val &= ~SYNQUACER_HSSPI_DMSTOP_STOP;
	writel(val, sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_FIFOCFG);
	val |= SYNQUACER_HSSPI_FIFOCFG_RX_FLUSH;
	val |= SYNQUACER_HSSPI_FIFOCFG_TX_FLUSH;
	writel(val, sspi->regs + SYNQUACER_HSSPI_REG_FIFOCFG);

	/*
	 * See if we can transfer 4-bytes as 1 word
	 * to maximize the FIFO buffer efficiency.
	 */
	bpw = xfer->bits_per_word;
	if (bpw == 8 && !(xfer->len % 4) && !(spi->mode & SPI_LSB_FIRST))
		xfer->bits_per_word = 32;

	ret = synquacer_spi_config(master, spi, xfer);

	/* restore */
	xfer->bits_per_word = bpw;

	if (ret)
		return ret;

	reinit_completion(&sspi->transfer_done);

	sspi->tx_buf = xfer->tx_buf;
	sspi->rx_buf = xfer->rx_buf;

	switch (sspi->bpw) {
	case 8:
		words = xfer->len;
		break;
	case 16:
		words = xfer->len / 2;
		break;
	case 24:
		/* fallthrough, should use 32-bits access */
	case 32:
		words = xfer->len / 4;
		break;
	default:
		dev_err(sspi->dev, "unsupported bpw: %d\n", sspi->bpw);
		return -EINVAL;
	}

	if (xfer->tx_buf)
		sspi->tx_words = words;
	else
		sspi->tx_words = 0;

	if (xfer->rx_buf)
		sspi->rx_words = words;
	else
		sspi->rx_words = 0;

	if (xfer->tx_buf) {
		status = write_fifo(sspi);
		if (status < 0) {
			dev_err(sspi->dev, "failed write_fifo. status: 0x%x\n",
				status);
			return status;
		}
	}

	if (xfer->rx_buf) {
		val = readl(sspi->regs + SYNQUACER_HSSPI_REG_FIFOCFG);
		val &= ~(SYNQUACER_HSSPI_FIFOCFG_RX_THRESHOLD_MASK <<
			 SYNQUACER_HSSPI_FIFOCFG_RX_THRESHOLD_SHIFT);
		val |= ((sspi->rx_words > SYNQUACER_HSSPI_FIFO_DEPTH ?
			SYNQUACER_HSSPI_FIFO_RX_THRESHOLD : sspi->rx_words) <<
			SYNQUACER_HSSPI_FIFOCFG_RX_THRESHOLD_SHIFT);
		writel(val, sspi->regs + SYNQUACER_HSSPI_REG_FIFOCFG);
	}

	writel(~0, sspi->regs + SYNQUACER_HSSPI_REG_TXC);
	writel(~0, sspi->regs + SYNQUACER_HSSPI_REG_RXC);

	/* Trigger */
	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);
	val |= SYNQUACER_HSSPI_DMSTART_START;
	writel(val, sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);

	if (xfer->tx_buf) {
		val = SYNQUACER_HSSPI_TXE_FIFO_EMPTY;
		writel(val, sspi->regs + SYNQUACER_HSSPI_REG_TXE);
		status = wait_for_completion_timeout(&sspi->transfer_done,
			msecs_to_jiffies(SYNQUACER_HSSPI_TRANSFER_TMOUT_MSEC));
		writel(0, sspi->regs + SYNQUACER_HSSPI_REG_TXE);
	}

	if (xfer->rx_buf) {
		u32 buf[SYNQUACER_HSSPI_FIFO_DEPTH];

		val = SYNQUACER_HSSPI_RXE_FIFO_MORE_THAN_THRESHOLD |
		      SYNQUACER_HSSPI_RXE_SLAVE_RELEASED;
		writel(val, sspi->regs + SYNQUACER_HSSPI_REG_RXE);
		status = wait_for_completion_timeout(&sspi->transfer_done,
			msecs_to_jiffies(SYNQUACER_HSSPI_TRANSFER_TMOUT_MSEC));
		writel(0, sspi->regs + SYNQUACER_HSSPI_REG_RXE);

		/* stop RX and clean RXFIFO */
		val = readl(sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);
		val |= SYNQUACER_HSSPI_DMSTOP_STOP;
		writel(val, sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);
		sspi->rx_buf = buf;
		sspi->rx_words = SYNQUACER_HSSPI_FIFO_DEPTH;
		read_fifo(sspi);
	}

	if (status == 0) {
		dev_err(sspi->dev, "failed to transfer. Timeout.\n");
		return -ETIMEDOUT;
	}

	return 0;
}

static void synquacer_spi_set_cs(struct spi_device *spi, bool enable)
{
	struct synquacer_spi *sspi = spi_master_get_devdata(spi->master);
	u32 val;

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);
	val &= ~(SYNQUACER_HSSPI_DMPSEL_CS_MASK <<
		 SYNQUACER_HSSPI_DMPSEL_CS_SHIFT);
	val |= spi->chip_select << SYNQUACER_HSSPI_DMPSEL_CS_SHIFT;

	if (!enable)
		val |= SYNQUACER_HSSPI_DMSTOP_STOP;

	writel(val, sspi->regs + SYNQUACER_HSSPI_REG_DMSTART);
}

static int synquacer_spi_wait_status_update(struct synquacer_spi *sspi,
					    bool enable)
{
	u32 val;
	unsigned long timeout = jiffies +
		msecs_to_jiffies(SYNQUACER_HSSPI_ENABLE_TMOUT_MSEC);

	/* wait MES(Module Enable Status) is updated */
	do {
		val = readl(sspi->regs + SYNQUACER_HSSPI_REG_MCTRL) &
		      SYNQUACER_HSSPI_MCTRL_MES;
		if (enable && val)
			return 0;
		if (!enable && !val)
			return 0;
	} while (time_before(jiffies, timeout));

	dev_err(sspi->dev, "timeout occurs in updating Module Enable Status\n");
	return -EBUSY;
}

static int synquacer_spi_enable(struct spi_master *master)
{
	u32 val;
	int status;
	struct synquacer_spi *sspi = spi_master_get_devdata(master);

	/* Disable module */
	writel(0, sspi->regs + SYNQUACER_HSSPI_REG_MCTRL);
	status = synquacer_spi_wait_status_update(sspi, false);
	if (status < 0)
		return status;

	writel(0, sspi->regs + SYNQUACER_HSSPI_REG_TXE);
	writel(0, sspi->regs + SYNQUACER_HSSPI_REG_RXE);
	writel(~0, sspi->regs + SYNQUACER_HSSPI_REG_TXC);
	writel(~0, sspi->regs + SYNQUACER_HSSPI_REG_RXC);
	writel(~0, sspi->regs + SYNQUACER_HSSPI_REG_FAULTC);

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_DMCFG);
	val &= ~SYNQUACER_HSSPI_DMCFG_SSDC;
	val &= ~SYNQUACER_HSSPI_DMCFG_MSTARTEN;
	writel(val, sspi->regs + SYNQUACER_HSSPI_REG_DMCFG);

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_MCTRL);
	if (sspi->clk_src_type == SYNQUACER_HSSPI_CLOCK_SRC_IPCLK)
		val |= SYNQUACER_HSSPI_MCTRL_CDSS;
	else
		val &= ~SYNQUACER_HSSPI_MCTRL_CDSS;

	val &= ~SYNQUACER_HSSPI_MCTRL_COMMAND_SEQUENCE_EN;
	val |= SYNQUACER_HSSPI_MCTRL_MEN;
	val |= SYNQUACER_HSSPI_MCTRL_SYNCON;

	/* Enable module */
	writel(val, sspi->regs + SYNQUACER_HSSPI_REG_MCTRL);
	status = synquacer_spi_wait_status_update(sspi, true);
	if (status < 0)
		return status;

	return 0;
}

static irqreturn_t sq_spi_rx_handler(int irq, void *priv)
{
	uint32_t val;
	struct synquacer_spi *sspi = priv;

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_RXF);
	if ((val & SYNQUACER_HSSPI_RXF_SLAVE_RELEASED) ||
	    (val & SYNQUACER_HSSPI_RXF_FIFO_MORE_THAN_THRESHOLD)) {
		read_fifo(sspi);

		if (sspi->rx_words == 0) {
			writel(0, sspi->regs + SYNQUACER_HSSPI_REG_RXE);
			complete(&sspi->transfer_done);
		}
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static irqreturn_t sq_spi_tx_handler(int irq, void *priv)
{
	uint32_t val;
	struct synquacer_spi *sspi = priv;

	val = readl(sspi->regs + SYNQUACER_HSSPI_REG_TXF);
	if (val & SYNQUACER_HSSPI_TXF_FIFO_EMPTY) {
		if (sspi->tx_words == 0) {
			writel(0, sspi->regs + SYNQUACER_HSSPI_REG_TXE);
			complete(&sspi->transfer_done);
		} else {
			write_fifo(sspi);
		}
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int synquacer_spi_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct spi_master *master;
	struct synquacer_spi *sspi;
	int ret;
	int rx_irq, tx_irq;

	master = spi_alloc_master(&pdev->dev, sizeof(*sspi));
	if (!master)
		return -ENOMEM;

	platform_set_drvdata(pdev, master);

	sspi = spi_master_get_devdata(master);
	sspi->dev = &pdev->dev;

	init_completion(&sspi->transfer_done);

	sspi->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(sspi->regs)) {
		ret = PTR_ERR(sspi->regs);
		goto put_spi;
	}

	sspi->clk_src_type = SYNQUACER_HSSPI_CLOCK_SRC_IHCLK; /* Default */
	device_property_read_u32(&pdev->dev, "socionext,ihclk-rate",
				 &master->max_speed_hz); /* for ACPI */

	if (dev_of_node(&pdev->dev)) {
		if (device_property_match_string(&pdev->dev,
					 "clock-names", "iHCLK") >= 0) {
			sspi->clk_src_type = SYNQUACER_HSSPI_CLOCK_SRC_IHCLK;
			sspi->clk = devm_clk_get(sspi->dev, "iHCLK");
		} else if (device_property_match_string(&pdev->dev,
						"clock-names", "iPCLK") >= 0) {
			sspi->clk_src_type = SYNQUACER_HSSPI_CLOCK_SRC_IPCLK;
			sspi->clk = devm_clk_get(sspi->dev, "iPCLK");
		} else {
			dev_err(&pdev->dev, "specified wrong clock source\n");
			ret = -EINVAL;
			goto put_spi;
		}

		if (IS_ERR(sspi->clk)) {
			ret = dev_err_probe(&pdev->dev, PTR_ERR(sspi->clk),
					    "clock not found\n");
			goto put_spi;
		}

		ret = clk_prepare_enable(sspi->clk);
		if (ret) {
			dev_err(&pdev->dev, "failed to enable clock (%d)\n",
				ret);
			goto put_spi;
		}

		master->max_speed_hz = clk_get_rate(sspi->clk);
	}

	if (!master->max_speed_hz) {
		dev_err(&pdev->dev, "missing clock source\n");
		ret = -EINVAL;
		goto disable_clk;
	}
	master->min_speed_hz = master->max_speed_hz / 254;

	sspi->aces = device_property_read_bool(&pdev->dev,
					       "socionext,set-aces");
	sspi->rtm = device_property_read_bool(&pdev->dev, "socionext,use-rtm");

	master->num_chipselect = SYNQUACER_HSSPI_NUM_CHIP_SELECT;

	rx_irq = platform_get_irq(pdev, 0);
	if (rx_irq <= 0) {
		ret = rx_irq;
		goto disable_clk;
	}
	snprintf(sspi->rx_irq_name, SYNQUACER_HSSPI_IRQ_NAME_MAX, "%s-rx",
		 dev_name(&pdev->dev));
	ret = devm_request_irq(&pdev->dev, rx_irq, sq_spi_rx_handler,
				0, sspi->rx_irq_name, sspi);
	if (ret) {
		dev_err(&pdev->dev, "request rx_irq failed (%d)\n", ret);
		goto disable_clk;
	}

	tx_irq = platform_get_irq(pdev, 1);
	if (tx_irq <= 0) {
		ret = tx_irq;
		goto disable_clk;
	}
	snprintf(sspi->tx_irq_name, SYNQUACER_HSSPI_IRQ_NAME_MAX, "%s-tx",
		 dev_name(&pdev->dev));
	ret = devm_request_irq(&pdev->dev, tx_irq, sq_spi_tx_handler,
				0, sspi->tx_irq_name, sspi);
	if (ret) {
		dev_err(&pdev->dev, "request tx_irq failed (%d)\n", ret);
		goto disable_clk;
	}

	master->dev.of_node = np;
	master->dev.fwnode = pdev->dev.fwnode;
	master->auto_runtime_pm = true;
	master->bus_num = pdev->id;

	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_TX_DUAL | SPI_RX_DUAL |
			    SPI_TX_QUAD | SPI_RX_QUAD;
	master->bits_per_word_mask = SPI_BPW_MASK(32) | SPI_BPW_MASK(24) |
				     SPI_BPW_MASK(16) | SPI_BPW_MASK(8);

	master->set_cs = synquacer_spi_set_cs;
	master->transfer_one = synquacer_spi_transfer_one;

	ret = synquacer_spi_enable(master);
	if (ret)
		goto disable_clk;

	pm_runtime_set_active(sspi->dev);
	pm_runtime_enable(sspi->dev);

	ret = devm_spi_register_master(sspi->dev, master);
	if (ret)
		goto disable_pm;

	return 0;

disable_pm:
	pm_runtime_disable(sspi->dev);
disable_clk:
	clk_disable_unprepare(sspi->clk);
put_spi:
	spi_master_put(master);

	return ret;
}

static int synquacer_spi_remove(struct platform_device *pdev)
{
	struct spi_master *master = platform_get_drvdata(pdev);
	struct synquacer_spi *sspi = spi_master_get_devdata(master);

	pm_runtime_disable(sspi->dev);

	clk_disable_unprepare(sspi->clk);

	return 0;
}

static int __maybe_unused synquacer_spi_suspend(struct device *dev)
{
	struct spi_master *master = dev_get_drvdata(dev);
	struct synquacer_spi *sspi = spi_master_get_devdata(master);
	int ret;

	ret = spi_master_suspend(master);
	if (ret)
		return ret;

	if (!pm_runtime_suspended(dev))
		clk_disable_unprepare(sspi->clk);

	return ret;
}

static int __maybe_unused synquacer_spi_resume(struct device *dev)
{
	struct spi_master *master = dev_get_drvdata(dev);
	struct synquacer_spi *sspi = spi_master_get_devdata(master);
	int ret;

	if (!pm_runtime_suspended(dev)) {
		/* Ensure reconfigure during next xfer */
		sspi->speed = 0;

		ret = clk_prepare_enable(sspi->clk);
		if (ret < 0) {
			dev_err(dev, "failed to enable clk (%d)\n",
				ret);
			return ret;
		}

		ret = synquacer_spi_enable(master);
		if (ret) {
			clk_disable_unprepare(sspi->clk);
			dev_err(dev, "failed to enable spi (%d)\n", ret);
			return ret;
		}
	}

	ret = spi_master_resume(master);
	if (ret < 0)
		clk_disable_unprepare(sspi->clk);

	return ret;
}

static SIMPLE_DEV_PM_OPS(synquacer_spi_pm_ops, synquacer_spi_suspend,
			 synquacer_spi_resume);

static const struct of_device_id synquacer_spi_of_match[] = {
	{.compatible = "socionext,synquacer-spi"},
	{}
};
MODULE_DEVICE_TABLE(of, synquacer_spi_of_match);

#ifdef CONFIG_ACPI
static const struct acpi_device_id synquacer_hsspi_acpi_ids[] = {
	{ "SCX0004" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(acpi, synquacer_hsspi_acpi_ids);
#endif

static struct platform_driver synquacer_spi_driver = {
	.driver = {
		.name = "synquacer-spi",
		.pm = &synquacer_spi_pm_ops,
		.of_match_table = synquacer_spi_of_match,
		.acpi_match_table = ACPI_PTR(synquacer_hsspi_acpi_ids),
	},
	.probe = synquacer_spi_probe,
	.remove = synquacer_spi_remove,
};
module_platform_driver(synquacer_spi_driver);

MODULE_DESCRIPTION("Socionext Synquacer HS-SPI controller driver");
MODULE_AUTHOR("Masahisa Kojima <masahisa.kojima@linaro.org>");
MODULE_AUTHOR("Jassi Brar <jaswinder.singh@linaro.org>");
MODULE_LICENSE("GPL v2");