[v3,2/2] spi: Add Socionext F_OSPI SPI flash controller driver

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index cb7e3a8ef3a5..c6fb8cd6d2ae 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -906,6 +906,15 @@  config SPI_SLAVE_MT27XX
 	  say Y or M here.If you are not sure, say N.
 	  SPI slave drivers for Mediatek MT27XX series ARM SoCs.
 
+config SPI_SN_F_OSPI
+	tristate "Socionext F_OSPI SPI flash controller"
+	depends on OF && HAS_IOMEM
+	depends on SPI_MEM
+	help
+	  This enables support for the Socionext F_OSPI controller
+	  for connecting an SPI Flash memory over up to 8-bit wide bus.
+	  It supports indirect access mode only.
+
 config SPI_SPRD
 	tristate "Spreadtrum SPI controller"
 	depends on ARCH_SPRD || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 60d0b2f611f1..971bd62e4481 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -121,6 +121,7 @@  obj-$(CONFIG_SPI_SH_MSIOF)		+= spi-sh-msiof.o
 obj-$(CONFIG_SPI_SH_SCI)		+= spi-sh-sci.o
 obj-$(CONFIG_SPI_SIFIVE)		+= spi-sifive.o
 obj-$(CONFIG_SPI_SLAVE_MT27XX)          += spi-slave-mt27xx.o
+obj-$(CONFIG_SPI_SN_F_OSPI)		+= spi-sn-f-ospi.o
 obj-$(CONFIG_SPI_SPRD)			+= spi-sprd.o
 obj-$(CONFIG_SPI_SPRD_ADI)		+= spi-sprd-adi.o
 obj-$(CONFIG_SPI_STM32) 		+= spi-stm32.o
diff --git a/drivers/spi/spi-sn-f-ospi.c b/drivers/spi/spi-sn-f-ospi.c
new file mode 100644
index 000000000000..348c6e1edd38
--- /dev/null
+++ b/drivers/spi/spi-sn-f-ospi.c
@@ -0,0 +1,703 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Socionext SPI flash controller F_OSPI driver
+ * Copyright (C) 2021 Socionext Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
+
+/* Registers */
+#define OSPI_PROT_CTL_INDIR			0x00
+#define   OSPI_PROT_MODE_DATA_MASK		GENMASK(31, 30)
+#define   OSPI_PROT_MODE_ALT_MASK		GENMASK(29, 28)
+#define   OSPI_PROT_MODE_ADDR_MASK		GENMASK(27, 26)
+#define   OSPI_PROT_MODE_CODE_MASK		GENMASK(25, 24)
+#define     OSPI_PROT_MODE_SINGLE		0
+#define     OSPI_PROT_MODE_DUAL			1
+#define     OSPI_PROT_MODE_QUAD			2
+#define     OSPI_PROT_MODE_OCTAL		3
+#define   OSPI_PROT_DATA_RATE_DATA		BIT(23)
+#define   OSPI_PROT_DATA_RATE_ALT		BIT(22)
+#define   OSPI_PROT_DATA_RATE_ADDR		BIT(21)
+#define   OSPI_PROT_DATA_RATE_CODE		BIT(20)
+#define     OSPI_PROT_SDR			0
+#define     OSPI_PROT_DDR			1
+#define   OSPI_PROT_BIT_POS_DATA		BIT(19)
+#define   OSPI_PROT_BIT_POS_ALT			BIT(18)
+#define   OSPI_PROT_BIT_POS_ADDR		BIT(17)
+#define   OSPI_PROT_BIT_POS_CODE		BIT(16)
+#define   OSPI_PROT_SAMP_EDGE			BIT(12)
+#define   OSPI_PROT_DATA_UNIT_MASK		GENMASK(11, 10)
+#define     OSPI_PROT_DATA_UNIT_1B		0
+#define     OSPI_PROT_DATA_UNIT_2B		1
+#define     OSPI_PROT_DATA_UNIT_4B		3
+#define   OSPI_PROT_TRANS_DIR_WRITE		BIT(9)
+#define   OSPI_PROT_DATA_EN			BIT(8)
+#define   OSPI_PROT_ALT_SIZE_MASK		GENMASK(7, 5)
+#define   OSPI_PROT_ADDR_SIZE_MASK		GENMASK(4, 2)
+#define   OSPI_PROT_CODE_SIZE_MASK		GENMASK(1, 0)
+
+#define OSPI_CLK_CTL				0x10
+#define   OSPI_CLK_CTL_BOOT_INT_CLK_EN		BIT(16)
+#define   OSPI_CLK_CTL_PHA			BIT(12)
+#define     OSPI_CLK_CTL_PHA_180		0
+#define     OSPI_CLK_CTL_PHA_90			1
+#define   OSPI_CLK_CTL_DIV			GENMASK(9, 8)
+#define     OSPI_CLK_CTL_DIV_1			0
+#define     OSPI_CLK_CTL_DIV_2			1
+#define     OSPI_CLK_CTL_DIV_4			2
+#define     OSPI_CLK_CTL_DIV_8			3
+#define   OSPI_CLK_CTL_INT_CLK_EN		BIT(0)
+
+#define OSPI_CS_CTL1				0x14
+#define OSPI_CS_CTL2				0x18
+#define OSPI_SSEL				0x20
+#define OSPI_CMD_IDX_INDIR			0x40
+#define OSPI_ADDR				0x50
+#define OSPI_ALT_INDIR				0x60
+#define OSPI_DMY_INDIR				0x70
+#define OSPI_DAT				0x80
+#define OSPI_DAT_SWP_INDIR			0x90
+
+#define OSPI_DAT_SIZE_INDIR			0xA0
+#define   OSPI_DAT_SIZE_EN			BIT(15)
+#define   OSPI_DAT_SIZE_MASK			GENMASK(10, 0)
+#define   OSPI_DAT_SIZE_MAX			(OSPI_DAT_SIZE_MASK + 1)
+
+#define OSPI_TRANS_CTL				0xC0
+#define   OSPI_TRANS_CTL_STOP_REQ		BIT(1)	/* RW1AC */
+#define   OSPI_TRANS_CTL_START_REQ		BIT(0)	/* RW1AC */
+
+#define OSPI_ACC_MODE				0xC4
+#define   OSPI_ACC_MODE_BOOT_DISABLE		BIT(0)
+
+#define OSPI_SWRST				0xD0
+#define   OSPI_SWRST_INDIR_WRITE_FIFO		BIT(9)	/* RW1AC */
+#define   OSPI_SWRST_INDIR_READ_FIFO		BIT(8)	/* RW1AC */
+
+#define OSPI_STAT				0xE0
+#define   OSPI_STAT_IS_AXI_WRITING		BIT(10)
+#define   OSPI_STAT_IS_AXI_READING		BIT(9)
+#define   OSPI_STAT_IS_SPI_INT_CLK_STOP		BIT(4)
+#define   OSPI_STAT_IS_SPI_IDLE			BIT(3)
+
+#define OSPI_IRQ				0xF0
+#define   OSPI_IRQ_CS_DEASSERT			BIT(8)
+#define   OSPI_IRQ_WRITE_BUF_READY		BIT(2)
+#define   OSPI_IRQ_READ_BUF_READY		BIT(1)
+#define   OSPI_IRQ_CS_TRANS_COMP		BIT(0)
+#define   OSPI_IRQ_ALL				\
+		(OSPI_IRQ_CS_DEASSERT | OSPI_IRQ_WRITE_BUF_READY \
+		 | OSPI_IRQ_READ_BUF_READY | OSPI_IRQ_CS_TRANS_COMP)
+
+#define OSPI_IRQ_STAT_EN			0xF4
+#define OSPI_IRQ_SIG_EN				0xF8
+
+/* Parameters */
+#define OSPI_NUM_CS				4
+#define OSPI_DUMMY_CYCLE_MAX			255
+#define OSPI_WAIT_MAX_MSEC			100
+
+struct f_ospi {
+	void __iomem *base;
+	struct device *dev;
+	struct clk *clk;
+	struct mutex mlock;
+};
+
+static u32 f_ospi_get_dummy_cycle(const struct spi_mem_op *op)
+{
+	return (op->dummy.nbytes * 8) / op->dummy.buswidth;
+}
+
+static void f_ospi_clear_irq(struct f_ospi *ospi)
+{
+	writel(OSPI_IRQ_CS_DEASSERT | OSPI_IRQ_CS_TRANS_COMP,
+	       ospi->base + OSPI_IRQ);
+}
+
+static void f_ospi_enable_irq_status(struct f_ospi *ospi, u32 irq_bits)
+{
+	u32 val;
+
+	val = readl(ospi->base + OSPI_IRQ_STAT_EN);
+	val |= irq_bits;
+	writel(val, ospi->base + OSPI_IRQ_STAT_EN);
+}
+
+static void f_ospi_disable_irq_status(struct f_ospi *ospi, u32 irq_bits)
+{
+	u32 val;
+
+	val = readl(ospi->base + OSPI_IRQ_STAT_EN);
+	val &= ~irq_bits;
+	writel(val, ospi->base + OSPI_IRQ_STAT_EN);
+}
+
+static void f_ospi_disable_irq_output(struct f_ospi *ospi, u32 irq_bits)
+{
+	u32 val;
+
+	val = readl(ospi->base + OSPI_IRQ_SIG_EN);
+	val &= ~irq_bits;
+	writel(val, ospi->base + OSPI_IRQ_SIG_EN);
+}
+
+static int f_ospi_prepare_config(struct f_ospi *ospi)
+{
+	u32 val, stat0, stat1;
+
+	/* G4: Disable internal clock */
+	val = readl(ospi->base + OSPI_CLK_CTL);
+	val &= ~(OSPI_CLK_CTL_BOOT_INT_CLK_EN | OSPI_CLK_CTL_INT_CLK_EN);
+	writel(val, ospi->base + OSPI_CLK_CTL);
+
+	/* G5: Wait for stop */
+	stat0 = OSPI_STAT_IS_AXI_WRITING | OSPI_STAT_IS_AXI_READING;
+	stat1 = OSPI_STAT_IS_SPI_IDLE | OSPI_STAT_IS_SPI_INT_CLK_STOP;
+
+	return readl_poll_timeout(ospi->base + OSPI_STAT,
+				  val, (val & (stat0 | stat1)) == stat1,
+				  0, OSPI_WAIT_MAX_MSEC);
+}
+
+static int f_ospi_unprepare_config(struct f_ospi *ospi)
+{
+	u32 val;
+
+	/* G11: Enable internal clock */
+	val = readl(ospi->base + OSPI_CLK_CTL);
+	val |= OSPI_CLK_CTL_BOOT_INT_CLK_EN | OSPI_CLK_CTL_INT_CLK_EN;
+	writel(val, ospi->base + OSPI_CLK_CTL);
+
+	/* G12: Wait for clock to start */
+	return readl_poll_timeout(ospi->base + OSPI_STAT,
+				  val, !(val & OSPI_STAT_IS_SPI_INT_CLK_STOP),
+				  0, OSPI_WAIT_MAX_MSEC);
+}
+
+static void f_ospi_config_clk(struct f_ospi *ospi, u32 device_hz)
+{
+	long rate_hz = clk_get_rate(ospi->clk);
+	u32 div = DIV_ROUND_UP(rate_hz, device_hz);
+	u32 div_reg;
+	u32 val;
+
+	if (rate_hz < device_hz) {
+		dev_warn(ospi->dev, "Device frequency too large: %d\n",
+			 device_hz);
+		div_reg = OSPI_CLK_CTL_DIV_1;
+	} else {
+		if (div == 1) {
+			div_reg = OSPI_CLK_CTL_DIV_1;
+		} else if (div == 2) {
+			div_reg = OSPI_CLK_CTL_DIV_2;
+		} else if (div <= 4) {
+			div_reg = OSPI_CLK_CTL_DIV_4;
+		} else if (div <= 8) {
+			div_reg = OSPI_CLK_CTL_DIV_8;
+		} else {
+			dev_warn(ospi->dev, "Device frequency too small: %d\n",
+				 device_hz);
+			div_reg = OSPI_CLK_CTL_DIV_8;
+		}
+	}
+
+	/*
+	 * G7: Set clock mode
+	 * clock phase is fixed at 180 degrees and configure edge direction
+	 * instead.
+	 */
+	val = readl(ospi->base + OSPI_CLK_CTL);
+
+	val &= ~(OSPI_CLK_CTL_PHA | OSPI_CLK_CTL_DIV);
+	val |= FIELD_PREP(OSPI_CLK_CTL_PHA, OSPI_CLK_CTL_PHA_180)
+	     | FIELD_PREP(OSPI_CLK_CTL_DIV, div_reg);
+
+	writel(val, ospi->base + OSPI_CLK_CTL);
+}
+
+static void f_ospi_config_dll(struct f_ospi *ospi)
+{
+	/* G8: Configure DLL, nothing */
+}
+
+static u8 f_ospi_get_mode(struct f_ospi *ospi, int width, int data_size)
+{
+	u8 mode = OSPI_PROT_MODE_SINGLE;
+
+	switch (width) {
+	case 1:
+		mode = OSPI_PROT_MODE_SINGLE;
+		break;
+	case 2:
+		mode = OSPI_PROT_MODE_DUAL;
+		break;
+	case 4:
+		mode = OSPI_PROT_MODE_QUAD;
+		break;
+	case 8:
+		mode = OSPI_PROT_MODE_OCTAL;
+		break;
+	default:
+		if (data_size)
+			dev_err(ospi->dev, "Invalid buswidth: %d\n", width);
+		break;
+	}
+
+	return mode;
+}
+
+static void f_ospi_config_indir_protocol(struct f_ospi *ospi,
+					 struct spi_mem *mem,
+					 const struct spi_mem_op *op)
+{
+	struct spi_device *spi = mem->spi;
+	u8 mode;
+	u32 prot = 0, val;
+	int unit;
+
+	/* Set one chip select */
+	writel(BIT(spi->chip_select), ospi->base + OSPI_SSEL);
+
+	mode = f_ospi_get_mode(ospi, op->cmd.buswidth, 1);
+	prot |= FIELD_PREP(OSPI_PROT_MODE_CODE_MASK, mode);
+
+	mode = f_ospi_get_mode(ospi, op->addr.buswidth, op->addr.nbytes);
+	prot |= FIELD_PREP(OSPI_PROT_MODE_ADDR_MASK, mode);
+
+	mode = f_ospi_get_mode(ospi, op->data.buswidth, op->data.nbytes);
+	prot |= FIELD_PREP(OSPI_PROT_MODE_DATA_MASK, mode);
+
+	prot |= FIELD_PREP(OSPI_PROT_DATA_RATE_DATA, OSPI_PROT_SDR);
+	prot |= FIELD_PREP(OSPI_PROT_DATA_RATE_ALT,  OSPI_PROT_SDR);
+	prot |= FIELD_PREP(OSPI_PROT_DATA_RATE_ADDR, OSPI_PROT_SDR);
+	prot |= FIELD_PREP(OSPI_PROT_DATA_RATE_CODE, OSPI_PROT_SDR);
+
+	if (spi->mode & SPI_LSB_FIRST)
+		prot |= OSPI_PROT_BIT_POS_DATA | OSPI_PROT_BIT_POS_ALT
+		      | OSPI_PROT_BIT_POS_ADDR | OSPI_PROT_BIT_POS_CODE;
+
+	if (spi->mode & SPI_CPHA)
+		prot |= OSPI_PROT_SAMP_EDGE;
+
+	/* Examine nbytes % 4 */
+	switch (op->data.nbytes & 0x3) {
+	case 0:
+		unit = OSPI_PROT_DATA_UNIT_4B;
+		val = 0;
+		break;
+	case 2:
+		unit = OSPI_PROT_DATA_UNIT_2B;
+		val = OSPI_DAT_SIZE_EN | (op->data.nbytes - 1);
+		break;
+	default:
+		unit = OSPI_PROT_DATA_UNIT_1B;
+		val = OSPI_DAT_SIZE_EN | (op->data.nbytes - 1);
+		break;
+	}
+	prot |= FIELD_PREP(OSPI_PROT_DATA_UNIT_MASK, unit);
+
+	switch (op->data.dir) {
+	case SPI_MEM_DATA_IN:
+		prot |= OSPI_PROT_DATA_EN;
+		break;
+
+	case SPI_MEM_DATA_OUT:
+		prot |= OSPI_PROT_TRANS_DIR_WRITE | OSPI_PROT_DATA_EN;
+		break;
+
+	case SPI_MEM_NO_DATA:
+		prot |= OSPI_PROT_TRANS_DIR_WRITE;
+		break;
+
+	default:
+		dev_warn(ospi->dev, "Unsupported direction");
+		break;
+	}
+
+	prot |= FIELD_PREP(OSPI_PROT_ADDR_SIZE_MASK, op->addr.nbytes);
+	prot |= FIELD_PREP(OSPI_PROT_CODE_SIZE_MASK, 1);	/* 1byte */
+
+	writel(prot, ospi->base + OSPI_PROT_CTL_INDIR);
+	writel(val, ospi->base + OSPI_DAT_SIZE_INDIR);
+}
+
+static int f_ospi_indir_prepare_op(struct f_ospi *ospi, struct spi_mem *mem,
+				   const struct spi_mem_op *op)
+{
+	struct spi_device *spi = mem->spi;
+	u32 irq_stat_en;
+	int ret;
+
+	ret = f_ospi_prepare_config(ospi);
+	if (ret)
+		return ret;
+
+	f_ospi_config_clk(ospi, spi->max_speed_hz);
+
+	f_ospi_config_indir_protocol(ospi, mem, op);
+
+	writel(f_ospi_get_dummy_cycle(op), ospi->base + OSPI_DMY_INDIR);
+	writel(op->addr.val, ospi->base + OSPI_ADDR);
+	writel(op->cmd.opcode, ospi->base + OSPI_CMD_IDX_INDIR);
+
+	f_ospi_clear_irq(ospi);
+
+	switch (op->data.dir) {
+	case SPI_MEM_DATA_IN:
+		irq_stat_en = OSPI_IRQ_READ_BUF_READY | OSPI_IRQ_CS_TRANS_COMP;
+		break;
+
+	case SPI_MEM_DATA_OUT:
+		irq_stat_en = OSPI_IRQ_WRITE_BUF_READY | OSPI_IRQ_CS_TRANS_COMP;
+		break;
+
+	case SPI_MEM_NO_DATA:
+		irq_stat_en = OSPI_IRQ_CS_TRANS_COMP;
+		break;
+
+	default:
+		dev_warn(ospi->dev, "Unsupported direction");
+		irq_stat_en = 0;
+	}
+
+	f_ospi_disable_irq_status(ospi, ~irq_stat_en);
+	f_ospi_enable_irq_status(ospi, irq_stat_en);
+
+	return f_ospi_unprepare_config(ospi);
+}
+
+static void f_ospi_indir_start_xfer(struct f_ospi *ospi)
+{
+	/* Write only 1, auto cleared */
+	writel(OSPI_TRANS_CTL_START_REQ, ospi->base + OSPI_TRANS_CTL);
+}
+
+static void f_ospi_indir_stop_xfer(struct f_ospi *ospi)
+{
+	/* Write only 1, auto cleared */
+	writel(OSPI_TRANS_CTL_STOP_REQ, ospi->base + OSPI_TRANS_CTL);
+}
+
+static int f_ospi_indir_wait_xfer_complete(struct f_ospi *ospi)
+{
+	u32 val;
+
+	return readl_poll_timeout(ospi->base + OSPI_IRQ, val,
+				  val & OSPI_IRQ_CS_TRANS_COMP,
+				  0, OSPI_WAIT_MAX_MSEC);
+}
+
+static int f_ospi_indir_read(struct f_ospi *ospi, struct spi_mem *mem,
+			     const struct spi_mem_op *op)
+{
+	u8 *buf = op->data.buf.in;
+	u32 val;
+	int i, ret;
+
+	mutex_lock(&ospi->mlock);
+
+	/* E1-2: Prepare transfer operation */
+	ret = f_ospi_indir_prepare_op(ospi, mem, op);
+	if (ret)
+		goto out;
+
+	f_ospi_indir_start_xfer(ospi);
+
+	/* E3-4: Wait for ready and read data */
+	for (i = 0; i < op->data.nbytes; i++) {
+		ret = readl_poll_timeout(ospi->base + OSPI_IRQ, val,
+					 val & OSPI_IRQ_READ_BUF_READY,
+					 0, OSPI_WAIT_MAX_MSEC);
+		if (ret)
+			goto out;
+
+		buf[i] = readl(ospi->base + OSPI_DAT) & 0xFF;
+	}
+
+	/* E5-6: Stop transfer if data size is nothing */
+	if (!(readl(ospi->base + OSPI_DAT_SIZE_INDIR) & OSPI_DAT_SIZE_EN))
+		f_ospi_indir_stop_xfer(ospi);
+
+	/* E7-8: Wait for completion and clear */
+	ret = f_ospi_indir_wait_xfer_complete(ospi);
+	if (ret)
+		goto out;
+
+	writel(OSPI_IRQ_CS_TRANS_COMP, ospi->base + OSPI_IRQ);
+
+	/* E9: Do nothing if data size is valid */
+	if (readl(ospi->base + OSPI_DAT_SIZE_INDIR) & OSPI_DAT_SIZE_EN)
+		goto out;
+
+	/* E10-11: Reset and check read fifo */
+	writel(OSPI_SWRST_INDIR_READ_FIFO, ospi->base + OSPI_SWRST);
+
+	ret = readl_poll_timeout(ospi->base + OSPI_SWRST, val,
+				 !(val & OSPI_SWRST_INDIR_READ_FIFO),
+				 0, OSPI_WAIT_MAX_MSEC);
+out:
+	mutex_unlock(&ospi->mlock);
+
+	return ret;
+}
+
+static int f_ospi_indir_write(struct f_ospi *ospi, struct spi_mem *mem,
+			      const struct spi_mem_op *op)
+{
+	u8 *buf = (u8 *)op->data.buf.out;
+	u32 val;
+	int i, ret;
+
+	mutex_lock(&ospi->mlock);
+
+	/* F1-3: Prepare transfer operation */
+	ret = f_ospi_indir_prepare_op(ospi, mem, op);
+	if (ret)
+		goto out;
+
+	f_ospi_indir_start_xfer(ospi);
+
+	if (!(readl(ospi->base + OSPI_PROT_CTL_INDIR) & OSPI_PROT_DATA_EN))
+		goto nodata;
+
+	/* F4-5: Wait for buffer ready and write data */
+	for (i = 0; i < op->data.nbytes; i++) {
+		ret = readl_poll_timeout(ospi->base + OSPI_IRQ, val,
+					 val & OSPI_IRQ_WRITE_BUF_READY,
+					 0, OSPI_WAIT_MAX_MSEC);
+		if (ret)
+			goto out;
+
+		writel(buf[i], ospi->base + OSPI_DAT);
+	}
+
+	/* F6-7: Stop transfer if data size is nothing */
+	if (!(readl(ospi->base + OSPI_DAT_SIZE_INDIR) & OSPI_DAT_SIZE_EN))
+		f_ospi_indir_stop_xfer(ospi);
+
+nodata:
+	/* F8-9: Wait for completion and clear */
+	ret = f_ospi_indir_wait_xfer_complete(ospi);
+	if (ret)
+		goto out;
+
+	writel(OSPI_IRQ_CS_TRANS_COMP, ospi->base + OSPI_IRQ);
+out:
+	mutex_unlock(&ospi->mlock);
+
+	return ret;
+}
+
+static int f_ospi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct f_ospi *ospi = spi_controller_get_devdata(mem->spi->master);
+	int err = 0;
+
+	switch (op->data.dir) {
+	case SPI_MEM_DATA_IN:
+		err = f_ospi_indir_read(ospi, mem, op);
+		break;
+
+	case SPI_MEM_DATA_OUT:
+		fallthrough;
+	case SPI_MEM_NO_DATA:
+		err = f_ospi_indir_write(ospi, mem, op);
+		break;
+
+	default:
+		dev_warn(ospi->dev, "Unsupported direction");
+		err = -EOPNOTSUPP;
+	}
+
+	return err;
+}
+
+static bool f_ospi_supports_op_width(struct spi_mem *mem,
+				     const struct spi_mem_op *op)
+{
+	u8 width_available[] = { 0, 1, 2, 4, 8 };
+	u8 width_op[] = { op->cmd.buswidth, op->addr.buswidth,
+			  op->dummy.buswidth, op->data.buswidth };
+	bool is_match_found;
+	int i, j;
+
+	for (i = 0; i < ARRAY_SIZE(width_op); i++) {
+		is_match_found = false;
+
+		for (j = 0; j < ARRAY_SIZE(width_available); j++) {
+			if (width_op[i] == width_available[j]) {
+				is_match_found = true;
+				break;
+			}
+		}
+
+		if (!is_match_found)
+			return false;
+	}
+
+	return true;
+}
+
+static bool f_ospi_supports_op(struct spi_mem *mem,
+			       const struct spi_mem_op *op)
+{
+	if (f_ospi_get_dummy_cycle(op) > OSPI_DUMMY_CYCLE_MAX)
+		return false;
+
+	if (op->addr.nbytes > 4)
+		return false;
+
+	if (!f_ospi_supports_op_width(mem, op))
+		return false;
+
+	return true;
+}
+
+static int f_ospi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
+{
+	op->data.nbytes = min((int)op->data.nbytes, (int)(OSPI_DAT_SIZE_MAX));
+
+	return 0;
+}
+
+static const struct spi_controller_mem_ops f_ospi_mem_ops = {
+	.adjust_op_size = f_ospi_adjust_op_size,
+	.supports_op = f_ospi_supports_op,
+	.exec_op = f_ospi_exec_op,
+};
+
+static int f_ospi_init(struct f_ospi *ospi)
+{
+	int ret;
+
+	ret = f_ospi_prepare_config(ospi);
+	if (ret)
+		return ret;
+
+	/* Disable boot signal */
+	writel(OSPI_ACC_MODE_BOOT_DISABLE, ospi->base + OSPI_ACC_MODE);
+
+	f_ospi_config_dll(ospi);
+
+	/* Disable IRQ */
+	f_ospi_clear_irq(ospi);
+	f_ospi_disable_irq_status(ospi, OSPI_IRQ_ALL);
+	f_ospi_disable_irq_output(ospi, OSPI_IRQ_ALL);
+
+	return f_ospi_unprepare_config(ospi);
+}
+
+static int f_ospi_probe(struct platform_device *pdev)
+{
+	struct spi_controller *ctlr;
+	struct device *dev = &pdev->dev;
+	struct f_ospi *ospi;
+	u32 num_cs = OSPI_NUM_CS;
+	int ret;
+
+	ctlr = spi_alloc_master(dev, sizeof(*ospi));
+	if (!ctlr)
+		return -ENOMEM;
+
+	ctlr->mode_bits = SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL
+		| SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_OCTAL
+		| SPI_MODE_0 | SPI_MODE_1 | SPI_LSB_FIRST;
+	ctlr->mem_ops = &f_ospi_mem_ops;
+	ctlr->bus_num = -1;
+	of_property_read_u32(dev->of_node, "num-cs", &num_cs);
+	if (num_cs > OSPI_NUM_CS) {
+		dev_err(dev, "num-cs too large: %d\n", num_cs);
+		return -ENOMEM;
+	}
+	ctlr->num_chipselect = num_cs;
+	ctlr->dev.of_node = dev->of_node;
+
+	ospi = spi_controller_get_devdata(ctlr);
+	ospi->dev = dev;
+
+	platform_set_drvdata(pdev, ospi);
+
+	ospi->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ospi->base)) {
+		ret = PTR_ERR(ospi->base);
+		goto err_put_ctlr;
+	}
+
+	ospi->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(ospi->clk)) {
+		ret = PTR_ERR(ospi->clk);
+		goto err_put_ctlr;
+	}
+
+	ret = clk_prepare_enable(ospi->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable the clock\n");
+		goto err_disable_clk;
+	}
+
+	mutex_init(&ospi->mlock);
+
+	ret = f_ospi_init(ospi);
+	if (ret)
+		goto err_destroy_mutex;
+
+	ret = devm_spi_register_controller(dev, ctlr);
+	if (ret)
+		goto err_destroy_mutex;
+
+	return 0;
+
+err_destroy_mutex:
+	mutex_destroy(&ospi->mlock);
+
+err_disable_clk:
+	clk_disable_unprepare(ospi->clk);
+
+err_put_ctlr:
+	spi_controller_put(ctlr);
+
+	return ret;
+}
+
+static int f_ospi_remove(struct platform_device *pdev)
+{
+	struct f_ospi *ospi = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(ospi->clk);
+
+	mutex_destroy(&ospi->mlock);
+
+	return 0;
+}
+
+static const struct of_device_id f_ospi_dt_ids[] = {
+	{ .compatible = "socionext,f-ospi" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, f_ospi_dt_ids);
+
+static struct platform_driver f_ospi_driver = {
+	.driver = {
+		.name = "socionext,f-ospi",
+		.of_match_table = f_ospi_dt_ids,
+	},
+	.probe = f_ospi_probe,
+	.remove = f_ospi_remove,
+};
+module_platform_driver(f_ospi_driver);
+
+MODULE_DESCRIPTION("Socionext F_OSPI controller driver");
+MODULE_AUTHOR("Socionext Inc.");
+MODULE_AUTHOR("Kunihiko Hayashi <hayashi.kunihiko@socionext.com>");
+MODULE_LICENSE("GPL");