mtd: spi-nor: add driver for STM32 quad spi flash controller

The quadspi is a specialized communication interface targeting single,
dual or quad SPI Flash memories.

It can operate in any of the following modes:
-indirect mode: all the operations are performed using the quadspi
 registers
-read memory-mapped mode: the external Flash memory is mapped to the
 microcontroller address space and is seen by the system as if it was
 an internal memory

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>

3 files changed, 701 insertions, 0 deletions

diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
index 7252087ef407..bfdfb1e72b38 100644
--- a/drivers/mtd/spi-nor/Kconfig
+++ b/drivers/mtd/spi-nor/Kconfig
@@ -106,4 +106,11 @@ config SPI_INTEL_SPI_PLATFORM
 	  To compile this driver as a module, choose M here: the module
 	  will be called intel-spi-platform.
 
+config SPI_STM32_QUADSPI
+	tristate "STM32 Quad SPI controller"
+	depends on ARCH_STM32
+	help
+	  This enables support for the STM32 Quad SPI controller.
+	  We only connect the NOR to this controller.
+
 endif # MTD_SPI_NOR
diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
index 72238a793198..285aab86c7ca 100644
--- a/drivers/mtd/spi-nor/Makefile
+++ b/drivers/mtd/spi-nor/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_MTD_MT81xx_NOR)    += mtk-quadspi.o
 obj-$(CONFIG_SPI_NXP_SPIFI)	+= nxp-spifi.o
 obj-$(CONFIG_SPI_INTEL_SPI)	+= intel-spi.o
 obj-$(CONFIG_SPI_INTEL_SPI_PLATFORM)	+= intel-spi-platform.o
+obj-$(CONFIG_SPI_STM32_QUADSPI)	+= stm32-quadspi.o
\ No newline at end of file
diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
new file mode 100644
index 000000000000..ae45f81b8cd3
--- /dev/null
+++ b/drivers/mtd/spi-nor/stm32-quadspi.c
@@ -0,0 +1,693 @@
+/*
+ * stm32_quadspi.c
+ *
+ * Copyright (C) 2017, Ludovic Barre
+ *
+ * License terms: GNU General Public License (GPL), version 2
+ */
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/spi-nor.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#define QUADSPI_CR		0x00
+#define CR_EN			BIT(0)
+#define CR_ABORT		BIT(1)
+#define CR_DMAEN		BIT(2)
+#define CR_TCEN			BIT(3)
+#define CR_SSHIFT		BIT(4)
+#define CR_DFM			BIT(6)
+#define CR_FSEL			BIT(7)
+#define CR_FTHRES_SHIFT		8
+#define CR_FTHRES_MASK		GENMASK(12, 8)
+#define CR_FTHRES(n)		(((n) << CR_FTHRES_SHIFT) & CR_FTHRES_MASK)
+#define CR_TEIE			BIT(16)
+#define CR_TCIE			BIT(17)
+#define CR_FTIE			BIT(18)
+#define CR_SMIE			BIT(19)
+#define CR_TOIE			BIT(20)
+#define CR_PRESC_SHIFT		24
+#define CR_PRESC_MASK		GENMASK(31, 24)
+#define CR_PRESC(n)		(((n) << CR_PRESC_SHIFT) & CR_PRESC_MASK)
+
+#define QUADSPI_DCR		0x04
+#define DCR_CSHT_SHIFT		8
+#define DCR_CSHT_MASK		GENMASK(10, 8)
+#define DCR_CSHT(n)		(((n) << DCR_CSHT_SHIFT) & DCR_CSHT_MASK)
+#define DCR_FSIZE_SHIFT		16
+#define DCR_FSIZE_MASK		GENMASK(20, 16)
+#define DCR_FSIZE(n)		(((n) << DCR_FSIZE_SHIFT) & DCR_FSIZE_MASK)
+
+#define QUADSPI_SR		0x08
+#define SR_TEF			BIT(0)
+#define SR_TCF			BIT(1)
+#define SR_FTF			BIT(2)
+#define SR_SMF			BIT(3)
+#define SR_TOF			BIT(4)
+#define SR_BUSY			BIT(5)
+#define SR_FLEVEL_SHIFT		8
+#define SR_FLEVEL_MASK		GENMASK(13, 8)
+
+#define QUADSPI_FCR		0x0c
+#define FCR_CTCF		BIT(1)
+
+#define QUADSPI_DLR		0x10
+
+#define QUADSPI_CCR		0x14
+#define CCR_INST_SHIFT		0
+#define CCR_INST_MASK		GENMASK(7, 0)
+#define CCR_INST(n)		(((n) << CCR_INST_SHIFT) & CCR_INST_MASK)
+#define CCR_IMODE_NONE		(0U << 8)
+#define CCR_IMODE_1		(1U << 8)
+#define CCR_IMODE_2		(2U << 8)
+#define CCR_IMODE_4		(3U << 8)
+#define CCR_ADMODE_NONE		(0U << 10)
+#define CCR_ADMODE_1		(1U << 10)
+#define CCR_ADMODE_2		(2U << 10)
+#define CCR_ADMODE_4		(3U << 10)
+#define CCR_ADSIZE_SHIFT	12
+#define CCR_ADSIZE_MASK		GENMASK(13, 12)
+#define CCR_ADSIZE(n)		(((n) << CCR_ADSIZE_SHIFT) & CCR_ADSIZE_MASK)
+#define CCR_ABMODE_NONE		(0U << 14)
+#define CCR_ABMODE_1		(1U << 14)
+#define CCR_ABMODE_2		(2U << 14)
+#define CCR_ABMODE_4		(3U << 14)
+#define CCR_ABSIZE_8		(0U << 16)
+#define CCR_ABSIZE_16		(1U << 16)
+#define CCR_ABSIZE_24		(2U << 16)
+#define CCR_ABSIZE_32		(3U << 16)
+#define CCR_DCYC_SHIFT		18
+#define CCR_DCYC_MASK		GENMASK(22, 18)
+#define CCR_DCYC(n)		(((n) << CCR_DCYC_SHIFT) & CCR_DCYC_MASK)
+#define CCR_DMODE_NONE		(0U << 24)
+#define CCR_DMODE_1		(1U << 24)
+#define CCR_DMODE_2		(2U << 24)
+#define CCR_DMODE_4		(3U << 24)
+#define CCR_FMODE_INDW		(0U << 26)
+#define CCR_FMODE_INDR		(1U << 26)
+#define CCR_FMODE_APM		(2U << 26)
+#define CCR_FMODE_MM		(3U << 26)
+
+#define QUADSPI_AR		0x18
+#define QUADSPI_ABR		0x1c
+#define QUADSPI_DR		0x20
+#define QUADSPI_PSMKR		0x24
+#define QUADSPI_PSMAR		0x28
+#define QUADSPI_PIR		0x2c
+#define QUADSPI_LPTR		0x30
+#define LPTR_DFT_TIMEOUT	0x10
+
+#define FSIZE_VAL(size)		(__fls(size) - 1)
+
+#define STM32_MAX_MMAP_SZ	SZ_256M
+#define STM32_MAX_NORCHIP	2
+
+#define STM32_QSPI_FIFO_TIMEOUT_US 30000
+#define STM32_QSPI_BUSY_TIMEOUT_US 100000
+
+struct stm32_qspi_flash {
+	struct spi_nor nor;
+	struct stm32_qspi *qspi;
+	u32 cs;
+	u32 fsize;
+	u32 presc;
+	u32 read_mode;
+	bool registered;
+};
+
+struct stm32_qspi {
+	struct device *dev;
+	void __iomem *io_base;
+	void __iomem *mm_base;
+	resource_size_t mm_size;
+	u32 nor_num;
+	struct clk *clk;
+	u32 clk_rate;
+	struct stm32_qspi_flash flash[STM32_MAX_NORCHIP];
+	struct completion cmd_completion;
+
+	/*
+	 * to protect device configuration, could be different between
+	 * 2 flash access (bk1, bk2)
+	 */
+	struct mutex lock;
+};
+
+struct stm32_qspi_cmd {
+	u8 addr_width;
+	u8 dummy;
+	bool tx_data;
+	u8 opcode;
+	u32 framemode;
+	u32 qspimode;
+	u32 addr;
+	size_t len;
+	void *buf;
+};
+
+static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi)
+{
+	u32 cr;
+	int err = 0;
+
+	if (readl_relaxed(qspi->io_base + QUADSPI_SR) & SR_TCF)
+		return 0;
+
+	reinit_completion(&qspi->cmd_completion);
+	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
+	writel_relaxed(cr | CR_TCIE, qspi->io_base + QUADSPI_CR);
+
+	if (!wait_for_completion_interruptible_timeout(&qspi->cmd_completion,
+						       msecs_to_jiffies(1000)))
+		err = -ETIMEDOUT;
+
+	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
+	return err;
+}
+
+static int stm32_qspi_wait_nobusy(struct stm32_qspi *qspi)
+{
+	u32 sr;
+
+	return readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR, sr,
+					  !(sr & SR_BUSY), 10,
+					  STM32_QSPI_BUSY_TIMEOUT_US);
+}
+
+static void stm32_qspi_set_framemode(struct spi_nor *nor,
+				     struct stm32_qspi_cmd *cmd, bool read)
+{
+	u32 dmode = CCR_DMODE_1;
+
+	cmd->framemode = CCR_IMODE_1;
+
+	if (read) {
+		switch (nor->flash_read) {
+		case SPI_NOR_NORMAL:
+		case SPI_NOR_FAST:
+			dmode = CCR_DMODE_1;
+			break;
+		case SPI_NOR_DUAL:
+			dmode = CCR_DMODE_2;
+			break;
+		case SPI_NOR_QUAD:
+			dmode = CCR_DMODE_4;
+			break;
+		}
+	}
+
+	cmd->framemode |= cmd->tx_data ? dmode : 0;
+	cmd->framemode |= cmd->addr_width ? CCR_ADMODE_1 : 0;
+}
+
+static void stm32_qspi_read_fifo(u8 *val, void __iomem *addr)
+{
+	*val = readb_relaxed(addr);
+}
+
+static void stm32_qspi_write_fifo(u8 *val, void __iomem *addr)
+{
+	writeb_relaxed(*val, addr);
+}
+
+static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
+			      const struct stm32_qspi_cmd *cmd)
+{
+	void (*tx_fifo)(u8 *, void __iomem *);
+	u32 len = cmd->len, sr;
+	u8 *buf = cmd->buf;
+	int ret;
+
+	if (cmd->qspimode == CCR_FMODE_INDW)
+		tx_fifo = stm32_qspi_write_fifo;
+	else
+		tx_fifo = stm32_qspi_read_fifo;
+
+	while (len--) {
+		ret = readl_relaxed_poll_timeout(qspi->io_base + QUADSPI_SR,
+						 sr, (sr & SR_FTF), 10,
+						 STM32_QSPI_FIFO_TIMEOUT_US);
+		if (ret) {
+			dev_err(qspi->dev, "fifo timeout (stat:%#x)\n", sr);
+			break;
+		}
+		tx_fifo(buf++, qspi->io_base + QUADSPI_DR);
+	}
+
+	return ret;
+}
+
+static int stm32_qspi_tx_mm(struct stm32_qspi *qspi,
+			    const struct stm32_qspi_cmd *cmd)
+{
+	memcpy_fromio(cmd->buf, qspi->mm_base + cmd->addr, cmd->len);
+	return 0;
+}
+
+static int stm32_qspi_tx(struct stm32_qspi *qspi,
+			 const struct stm32_qspi_cmd *cmd)
+{
+	if (!cmd->tx_data)
+		return 0;
+
+	if (cmd->qspimode == CCR_FMODE_MM)
+		return stm32_qspi_tx_mm(qspi, cmd);
+
+	return stm32_qspi_tx_poll(qspi, cmd);
+}
+
+static int stm32_qspi_send(struct stm32_qspi_flash *flash,
+			   const struct stm32_qspi_cmd *cmd)
+{
+	struct stm32_qspi *qspi = flash->qspi;
+	u32 ccr, dcr, cr;
+	int err;
+
+	err = stm32_qspi_wait_nobusy(qspi);
+	if (err)
+		goto abort;
+
+	dcr = readl_relaxed(qspi->io_base + QUADSPI_DCR) & ~DCR_FSIZE_MASK;
+	dcr |= DCR_FSIZE(flash->fsize);
+	writel_relaxed(dcr, qspi->io_base + QUADSPI_DCR);
+
+	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
+	cr &= ~CR_PRESC_MASK & ~CR_FSEL;
+	cr |= CR_PRESC(flash->presc);
+	cr |= flash->cs ? CR_FSEL : 0;
+	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
+
+	if (cmd->tx_data)
+		writel_relaxed(cmd->len - 1, qspi->io_base + QUADSPI_DLR);
+
+	ccr = cmd->framemode | cmd->qspimode;
+
+	if (cmd->dummy)
+		ccr |= CCR_DCYC(cmd->dummy);
+
+	if (cmd->addr_width)
+		ccr |= CCR_ADSIZE(cmd->addr_width - 1);
+
+	ccr |= CCR_INST(cmd->opcode);
+	writel_relaxed(ccr, qspi->io_base + QUADSPI_CCR);
+
+	if (cmd->addr_width && cmd->qspimode != CCR_FMODE_MM)
+		writel_relaxed(cmd->addr, qspi->io_base + QUADSPI_AR);
+
+	err = stm32_qspi_tx(qspi, cmd);
+	if (err)
+		goto abort;
+
+	if (cmd->qspimode != CCR_FMODE_MM) {
+		err = stm32_qspi_wait_cmd(qspi);
+		if (err)
+			goto abort;
+		writel_relaxed(FCR_CTCF, qspi->io_base + QUADSPI_FCR);
+	}
+
+	return err;
+
+abort:
+	cr = readl_relaxed(qspi->io_base + QUADSPI_CR) | CR_ABORT;
+	writel_relaxed(cr, qspi->io_base + QUADSPI_CR);
+
+	dev_err(qspi->dev, "%s abort err:%d\n", __func__, err);
+	return err;
+}
+
+static int stm32_qspi_read_reg(struct spi_nor *nor,
+			       u8 opcode, u8 *buf, int len)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct device *dev = flash->qspi->dev;
+	struct stm32_qspi_cmd cmd;
+
+	dev_dbg(dev, "read_reg: cmd:%#.2x buf:%p len:%#x\n", opcode, buf, len);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = opcode;
+	cmd.tx_data = true;
+	cmd.len = len;
+	cmd.buf = buf;
+	cmd.qspimode = CCR_FMODE_INDR;
+
+	stm32_qspi_set_framemode(nor, &cmd, false);
+
+	return stm32_qspi_send(flash, &cmd);
+}
+
+static int stm32_qspi_write_reg(struct spi_nor *nor, u8 opcode,
+				u8 *buf, int len)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct device *dev = flash->qspi->dev;
+	struct stm32_qspi_cmd cmd;
+
+	dev_dbg(dev, "write_reg: cmd:%#.2x buf:%p len:%#x\n", opcode, buf, len);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = opcode;
+	cmd.tx_data = !!(buf && len > 0);
+	cmd.len = len;
+	cmd.buf = buf;
+	cmd.qspimode = CCR_FMODE_INDW;
+
+	stm32_qspi_set_framemode(nor, &cmd, false);
+
+	return stm32_qspi_send(flash, &cmd);
+}
+
+static ssize_t stm32_qspi_read(struct spi_nor *nor, loff_t from, size_t len,
+			       u_char *buf)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct stm32_qspi *qspi = flash->qspi;
+	struct stm32_qspi_cmd cmd;
+	int err;
+
+	dev_dbg(qspi->dev, "read(%#.2x): buf:%p from:%#.8x len:%#x\n",
+		nor->read_opcode, buf, (u32)from, len);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = nor->read_opcode;
+	cmd.addr_width = nor->addr_width;
+	cmd.addr = (u32)from;
+	cmd.tx_data = true;
+	cmd.dummy = nor->read_dummy;
+	cmd.len = len;
+	cmd.buf = buf;
+	cmd.qspimode = flash->read_mode;
+
+	stm32_qspi_set_framemode(nor, &cmd, true);
+	err = stm32_qspi_send(flash, &cmd);
+
+	return err ? err : len;
+}
+
+static ssize_t stm32_qspi_write(struct spi_nor *nor, loff_t to, size_t len,
+				const u_char *buf)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct device *dev = flash->qspi->dev;
+	struct stm32_qspi_cmd cmd;
+	int err;
+
+	dev_dbg(dev, "write(%#.2x): buf:%p to:%#.8x len:%#x\n",
+		nor->program_opcode, buf, (u32)to, len);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = nor->program_opcode;
+	cmd.addr_width = nor->addr_width;
+	cmd.addr = (u32)to;
+	cmd.tx_data = true;
+	cmd.len = len;
+	cmd.buf = (void *)buf;
+	cmd.qspimode = CCR_FMODE_INDW;
+
+	stm32_qspi_set_framemode(nor, &cmd, false);
+	err = stm32_qspi_send(flash, &cmd);
+
+	return err ? err : len;
+}
+
+static int stm32_qspi_erase(struct spi_nor *nor, loff_t offs)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct device *dev = flash->qspi->dev;
+	struct stm32_qspi_cmd cmd;
+
+	dev_dbg(dev, "erase(%#.2x):offs:%#x\n", nor->erase_opcode, (u32)offs);
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.opcode = nor->erase_opcode;
+	cmd.addr_width = nor->addr_width;
+	cmd.addr = (u32)offs;
+	cmd.qspimode = CCR_FMODE_INDW;
+
+	stm32_qspi_set_framemode(nor, &cmd, false);
+
+	return stm32_qspi_send(flash, &cmd);
+}
+
+static irqreturn_t stm32_qspi_irq(int irq, void *dev_id)
+{
+	struct stm32_qspi *qspi = (struct stm32_qspi *)dev_id;
+	u32 cr, sr, fcr = 0;
+
+	cr = readl_relaxed(qspi->io_base + QUADSPI_CR);
+	sr = readl_relaxed(qspi->io_base + QUADSPI_SR);
+
+	if ((cr & CR_TCIE) && (sr & SR_TCF)) {
+		/* tx complete */
+		fcr |= FCR_CTCF;
+		complete(&qspi->cmd_completion);
+	} else {
+		dev_info_ratelimited(qspi->dev, "spurious interrupt\n");
+	}
+
+	writel_relaxed(fcr, qspi->io_base + QUADSPI_FCR);
+
+	return IRQ_HANDLED;
+}
+
+static int stm32_qspi_prep(struct spi_nor *nor, enum spi_nor_ops ops)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct stm32_qspi *qspi = flash->qspi;
+
+	mutex_lock(&qspi->lock);
+	return 0;
+}
+
+static void stm32_qspi_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
+{
+	struct stm32_qspi_flash *flash = nor->priv;
+	struct stm32_qspi *qspi = flash->qspi;
+
+	mutex_unlock(&qspi->lock);
+}
+
+static int stm32_qspi_flash_setup(struct stm32_qspi *qspi,
+				  struct device_node *np)
+{
+	u32 width, flash_read, presc, cs_num, max_rate = 0;
+	struct stm32_qspi_flash *flash;
+	struct mtd_info *mtd;
+	int ret;
+
+	of_property_read_u32(np, "reg", &cs_num);
+	if (cs_num >= STM32_MAX_NORCHIP)
+		return -EINVAL;
+
+	of_property_read_u32(np, "spi-max-frequency", &max_rate);
+	if (!max_rate)
+		return -EINVAL;
+
+	presc = DIV_ROUND_UP(qspi->clk_rate, max_rate) - 1;
+
+	if (of_property_read_u32(np, "spi-rx-bus-width", &width))
+		width = 1;
+
+	if (width == 4)
+		flash_read = SPI_NOR_QUAD;
+	else if (width == 2)
+		flash_read = SPI_NOR_DUAL;
+	else if (width == 1)
+		flash_read = SPI_NOR_NORMAL;
+	else
+		return -EINVAL;
+
+	flash = &qspi->flash[cs_num];
+	flash->qspi = qspi;
+	flash->cs = cs_num;
+	flash->presc = presc;
+
+	flash->nor.dev = qspi->dev;
+	spi_nor_set_flash_node(&flash->nor, np);
+	flash->nor.priv = flash;
+	mtd = &flash->nor.mtd;
+
+	flash->nor.read = stm32_qspi_read;
+	flash->nor.write = stm32_qspi_write;
+	flash->nor.erase = stm32_qspi_erase;
+	flash->nor.read_reg = stm32_qspi_read_reg;
+	flash->nor.write_reg = stm32_qspi_write_reg;
+	flash->nor.prepare = stm32_qspi_prep;
+	flash->nor.unprepare = stm32_qspi_unprep;
+
+	writel_relaxed(LPTR_DFT_TIMEOUT, qspi->io_base + QUADSPI_LPTR);
+
+	writel_relaxed(CR_PRESC(presc) | CR_FTHRES(3) | CR_TCEN | CR_SSHIFT
+		       | CR_EN, qspi->io_base + QUADSPI_CR);
+
+	/*
+	 * in stm32 qspi controller, QUADSPI_DCR register has a fsize field
+	 * which define the size of nor flash.
+	 * if fsize is NULL, the controller can't sent spi-nor command.
+	 * set a temporary value just to discover the nor flash with
+	 * "spi_nor_scan". After, the right value (mtd->size) can be set.
+	 */
+	flash->fsize = FSIZE_VAL(SZ_1K);
+
+	ret = spi_nor_scan(&flash->nor, NULL, flash_read);
+	if (ret) {
+		dev_err(qspi->dev, "device scan failed\n");
+		return ret;
+	}
+
+	flash->fsize = FSIZE_VAL(mtd->size);
+
+	flash->read_mode = CCR_FMODE_MM;
+	if (mtd->size > qspi->mm_size)
+		flash->read_mode = CCR_FMODE_INDR;
+
+	writel_relaxed(DCR_CSHT(1), qspi->io_base + QUADSPI_DCR);
+
+	ret = mtd_device_register(mtd, NULL, 0);
+	if (ret) {
+		dev_err(qspi->dev, "mtd device parse failed\n");
+		return ret;
+	}
+
+	flash->registered = true;
+
+	dev_dbg(qspi->dev, "read mm:%s cs:%d bus:%d\n",
+		flash->read_mode == CCR_FMODE_MM ? "yes" : "no", cs_num, width);
+
+	return 0;
+}
+
+static void stm32_qspi_mtd_free(struct stm32_qspi *qspi)
+{
+	int i;
+
+	for (i = 0; i < STM32_MAX_NORCHIP; i++)
+		if (qspi->flash[i].registered)
+			mtd_device_unregister(&qspi->flash[i].nor.mtd);
+}
+
+static int stm32_qspi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *flash_np;
+	struct reset_control *rstc;
+	struct stm32_qspi *qspi;
+	struct resource *res;
+	int ret, irq;
+
+	qspi = devm_kzalloc(dev, sizeof(*qspi), GFP_KERNEL);
+	if (!qspi)
+		return -ENOMEM;
+
+	qspi->nor_num = of_get_child_count(dev->of_node);
+	if (!qspi->nor_num || qspi->nor_num > STM32_MAX_NORCHIP)
+		return -ENODEV;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi");
+	qspi->io_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(qspi->io_base))
+		return PTR_ERR(qspi->io_base);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mm");
+	qspi->mm_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(qspi->mm_base))
+		return PTR_ERR(qspi->mm_base);
+
+	qspi->mm_size = resource_size(res);
+
+	irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(dev, irq, stm32_qspi_irq, 0,
+			       dev_name(dev), qspi);
+	if (ret) {
+		dev_err(dev, "failed to request irq\n");
+		return ret;
+	}
+
+	init_completion(&qspi->cmd_completion);
+
+	qspi->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(qspi->clk))
+		return PTR_ERR(qspi->clk);
+
+	qspi->clk_rate = clk_get_rate(qspi->clk);
+	if (!qspi->clk_rate)
+		return -EINVAL;
+
+	ret = clk_prepare_enable(qspi->clk);
+	if (ret) {
+		dev_err(dev, "can not enable the clock\n");
+		return ret;
+	}
+
+	rstc = devm_reset_control_get(dev, NULL);
+	if (!IS_ERR(rstc)) {
+		reset_control_assert(rstc);
+		udelay(2);
+		reset_control_deassert(rstc);
+	}
+
+	qspi->dev = dev;
+	platform_set_drvdata(pdev, qspi);
+	mutex_init(&qspi->lock);
+
+	for_each_available_child_of_node(dev->of_node, flash_np) {
+		ret = stm32_qspi_flash_setup(qspi, flash_np);
+		if (ret) {
+			dev_err(dev, "unable to setup flash chip\n");
+			goto err_flash;
+		}
+	}
+
+	return 0;
+
+err_flash:
+	mutex_destroy(&qspi->lock);
+	stm32_qspi_mtd_free(qspi);
+
+	clk_disable_unprepare(qspi->clk);
+	return ret;
+}
+
+static int stm32_qspi_remove(struct platform_device *pdev)
+{
+	struct stm32_qspi *qspi = platform_get_drvdata(pdev);
+
+	/* disable qspi */
+	writel_relaxed(0, qspi->io_base + QUADSPI_CR);
+
+	stm32_qspi_mtd_free(qspi);
+	mutex_destroy(&qspi->lock);
+
+	clk_disable_unprepare(qspi->clk);
+	return 0;
+}
+
+static const struct of_device_id stm32_qspi_match[] = {
+	{.compatible = "st,stm32f469-qspi"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, stm32_qspi_match);
+
+static struct platform_driver stm32_qspi_driver = {
+	.probe	= stm32_qspi_probe,
+	.remove	= stm32_qspi_remove,
+	.driver	= {
+		.name = "stm32-quadspi",
+		.of_match_table = stm32_qspi_match,
+	},
+};
+module_platform_driver(stm32_qspi_driver);
+
+MODULE_AUTHOR("Ludovic Barre <ludovic.barre@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 quad spi driver");
+MODULE_LICENSE("GPL v2");