Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 946 insertions, 0 deletions

diff --git a/drivers/spi/spi-armada-3700.c b/drivers/spi/spi-armada-3700.c
new file mode 100644
index 000000000..d8715954f
--- /dev/null
+++ b/drivers/spi/spi-armada-3700.c
@@ -0,0 +1,946 @@
+/*
+ * Marvell Armada-3700 SPI controller driver
+ *
+ * Copyright (C) 2016 Marvell Ltd.
+ *
+ * Author: Wilson Ding <dingwei@marvell.com>
+ * Author: Romain Perier <romain.perier@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/spi/spi.h>
+
+#define DRIVER_NAME			"armada_3700_spi"
+
+#define A3700_SPI_MAX_SPEED_HZ		100000000
+#define A3700_SPI_MAX_PRESCALE		30
+#define A3700_SPI_TIMEOUT		10
+
+/* SPI Register Offest */
+#define A3700_SPI_IF_CTRL_REG		0x00
+#define A3700_SPI_IF_CFG_REG		0x04
+#define A3700_SPI_DATA_OUT_REG		0x08
+#define A3700_SPI_DATA_IN_REG		0x0C
+#define A3700_SPI_IF_INST_REG		0x10
+#define A3700_SPI_IF_ADDR_REG		0x14
+#define A3700_SPI_IF_RMODE_REG		0x18
+#define A3700_SPI_IF_HDR_CNT_REG	0x1C
+#define A3700_SPI_IF_DIN_CNT_REG	0x20
+#define A3700_SPI_IF_TIME_REG		0x24
+#define A3700_SPI_INT_STAT_REG		0x28
+#define A3700_SPI_INT_MASK_REG		0x2C
+
+/* A3700_SPI_IF_CTRL_REG */
+#define A3700_SPI_EN			BIT(16)
+#define A3700_SPI_ADDR_NOT_CONFIG	BIT(12)
+#define A3700_SPI_WFIFO_OVERFLOW	BIT(11)
+#define A3700_SPI_WFIFO_UNDERFLOW	BIT(10)
+#define A3700_SPI_RFIFO_OVERFLOW	BIT(9)
+#define A3700_SPI_RFIFO_UNDERFLOW	BIT(8)
+#define A3700_SPI_WFIFO_FULL		BIT(7)
+#define A3700_SPI_WFIFO_EMPTY		BIT(6)
+#define A3700_SPI_RFIFO_FULL		BIT(5)
+#define A3700_SPI_RFIFO_EMPTY		BIT(4)
+#define A3700_SPI_WFIFO_RDY		BIT(3)
+#define A3700_SPI_RFIFO_RDY		BIT(2)
+#define A3700_SPI_XFER_RDY		BIT(1)
+#define A3700_SPI_XFER_DONE		BIT(0)
+
+/* A3700_SPI_IF_CFG_REG */
+#define A3700_SPI_WFIFO_THRS		BIT(28)
+#define A3700_SPI_RFIFO_THRS		BIT(24)
+#define A3700_SPI_AUTO_CS		BIT(20)
+#define A3700_SPI_DMA_RD_EN		BIT(18)
+#define A3700_SPI_FIFO_MODE		BIT(17)
+#define A3700_SPI_SRST			BIT(16)
+#define A3700_SPI_XFER_START		BIT(15)
+#define A3700_SPI_XFER_STOP		BIT(14)
+#define A3700_SPI_INST_PIN		BIT(13)
+#define A3700_SPI_ADDR_PIN		BIT(12)
+#define A3700_SPI_DATA_PIN1		BIT(11)
+#define A3700_SPI_DATA_PIN0		BIT(10)
+#define A3700_SPI_FIFO_FLUSH		BIT(9)
+#define A3700_SPI_RW_EN			BIT(8)
+#define A3700_SPI_CLK_POL		BIT(7)
+#define A3700_SPI_CLK_PHA		BIT(6)
+#define A3700_SPI_BYTE_LEN		BIT(5)
+#define A3700_SPI_CLK_PRESCALE		BIT(0)
+#define A3700_SPI_CLK_PRESCALE_MASK	(0x1f)
+#define A3700_SPI_CLK_EVEN_OFFS		(0x10)
+
+#define A3700_SPI_WFIFO_THRS_BIT	28
+#define A3700_SPI_RFIFO_THRS_BIT	24
+#define A3700_SPI_FIFO_THRS_MASK	0x7
+
+#define A3700_SPI_DATA_PIN_MASK		0x3
+
+/* A3700_SPI_IF_HDR_CNT_REG */
+#define A3700_SPI_DUMMY_CNT_BIT		12
+#define A3700_SPI_DUMMY_CNT_MASK	0x7
+#define A3700_SPI_RMODE_CNT_BIT		8
+#define A3700_SPI_RMODE_CNT_MASK	0x3
+#define A3700_SPI_ADDR_CNT_BIT		4
+#define A3700_SPI_ADDR_CNT_MASK		0x7
+#define A3700_SPI_INSTR_CNT_BIT		0
+#define A3700_SPI_INSTR_CNT_MASK	0x3
+
+/* A3700_SPI_IF_TIME_REG */
+#define A3700_SPI_CLK_CAPT_EDGE		BIT(7)
+
+struct a3700_spi {
+	struct spi_master *master;
+	void __iomem *base;
+	struct clk *clk;
+	unsigned int irq;
+	unsigned int flags;
+	bool xmit_data;
+	const u8 *tx_buf;
+	u8 *rx_buf;
+	size_t buf_len;
+	u8 byte_len;
+	u32 wait_mask;
+	struct completion done;
+};
+
+static u32 spireg_read(struct a3700_spi *a3700_spi, u32 offset)
+{
+	return readl(a3700_spi->base + offset);
+}
+
+static void spireg_write(struct a3700_spi *a3700_spi, u32 offset, u32 data)
+{
+	writel(data, a3700_spi->base + offset);
+}
+
+static void a3700_spi_auto_cs_unset(struct a3700_spi *a3700_spi)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val &= ~A3700_SPI_AUTO_CS;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_activate_cs(struct a3700_spi *a3700_spi, unsigned int cs)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	val |= (A3700_SPI_EN << cs);
+	spireg_write(a3700_spi, A3700_SPI_IF_CTRL_REG, val);
+}
+
+static void a3700_spi_deactivate_cs(struct a3700_spi *a3700_spi,
+				    unsigned int cs)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	val &= ~(A3700_SPI_EN << cs);
+	spireg_write(a3700_spi, A3700_SPI_IF_CTRL_REG, val);
+}
+
+static int a3700_spi_pin_mode_set(struct a3700_spi *a3700_spi,
+				  unsigned int pin_mode, bool receiving)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val &= ~(A3700_SPI_INST_PIN | A3700_SPI_ADDR_PIN);
+	val &= ~(A3700_SPI_DATA_PIN0 | A3700_SPI_DATA_PIN1);
+
+	switch (pin_mode) {
+	case SPI_NBITS_SINGLE:
+		break;
+	case SPI_NBITS_DUAL:
+		val |= A3700_SPI_DATA_PIN0;
+		break;
+	case SPI_NBITS_QUAD:
+		val |= A3700_SPI_DATA_PIN1;
+		/* RX during address reception uses 4-pin */
+		if (receiving)
+			val |= A3700_SPI_ADDR_PIN;
+		break;
+	default:
+		dev_err(&a3700_spi->master->dev, "wrong pin mode %u", pin_mode);
+		return -EINVAL;
+	}
+
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	return 0;
+}
+
+static void a3700_spi_fifo_mode_set(struct a3700_spi *a3700_spi, bool enable)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	if (enable)
+		val |= A3700_SPI_FIFO_MODE;
+	else
+		val &= ~A3700_SPI_FIFO_MODE;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_mode_set(struct a3700_spi *a3700_spi,
+			       unsigned int mode_bits)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+
+	if (mode_bits & SPI_CPOL)
+		val |= A3700_SPI_CLK_POL;
+	else
+		val &= ~A3700_SPI_CLK_POL;
+
+	if (mode_bits & SPI_CPHA)
+		val |= A3700_SPI_CLK_PHA;
+	else
+		val &= ~A3700_SPI_CLK_PHA;
+
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_clock_set(struct a3700_spi *a3700_spi,
+				unsigned int speed_hz)
+{
+	u32 val;
+	u32 prescale;
+
+	prescale = DIV_ROUND_UP(clk_get_rate(a3700_spi->clk), speed_hz);
+
+	/* For prescaler values over 15, we can only set it by steps of 2.
+	 * Starting from A3700_SPI_CLK_EVEN_OFFS, we set values from 0 up to
+	 * 30. We only use this range from 16 to 30.
+	 */
+	if (prescale > 15)
+		prescale = A3700_SPI_CLK_EVEN_OFFS + DIV_ROUND_UP(prescale, 2);
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val = val & ~A3700_SPI_CLK_PRESCALE_MASK;
+
+	val = val | (prescale & A3700_SPI_CLK_PRESCALE_MASK);
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	if (prescale <= 2) {
+		val = spireg_read(a3700_spi, A3700_SPI_IF_TIME_REG);
+		val |= A3700_SPI_CLK_CAPT_EDGE;
+		spireg_write(a3700_spi, A3700_SPI_IF_TIME_REG, val);
+	}
+}
+
+static void a3700_spi_bytelen_set(struct a3700_spi *a3700_spi, unsigned int len)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	if (len == 4)
+		val |= A3700_SPI_BYTE_LEN;
+	else
+		val &= ~A3700_SPI_BYTE_LEN;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	a3700_spi->byte_len = len;
+}
+
+static int a3700_spi_fifo_flush(struct a3700_spi *a3700_spi)
+{
+	int timeout = A3700_SPI_TIMEOUT;
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val |= A3700_SPI_FIFO_FLUSH;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	while (--timeout) {
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		if (!(val & A3700_SPI_FIFO_FLUSH))
+			return 0;
+		udelay(1);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int a3700_spi_init(struct a3700_spi *a3700_spi)
+{
+	struct spi_master *master = a3700_spi->master;
+	u32 val;
+	int i, ret = 0;
+
+	/* Reset SPI unit */
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val |= A3700_SPI_SRST;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	udelay(A3700_SPI_TIMEOUT);
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val &= ~A3700_SPI_SRST;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	/* Disable AUTO_CS and deactivate all chip-selects */
+	a3700_spi_auto_cs_unset(a3700_spi);
+	for (i = 0; i < master->num_chipselect; i++)
+		a3700_spi_deactivate_cs(a3700_spi, i);
+
+	/* Enable FIFO mode */
+	a3700_spi_fifo_mode_set(a3700_spi, true);
+
+	/* Set SPI mode */
+	a3700_spi_mode_set(a3700_spi, master->mode_bits);
+
+	/* Reset counters */
+	spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG, 0);
+
+	/* Mask the interrupts and clear cause bits */
+	spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_INT_STAT_REG, ~0U);
+
+	return ret;
+}
+
+static irqreturn_t a3700_spi_interrupt(int irq, void *dev_id)
+{
+	struct spi_master *master = dev_id;
+	struct a3700_spi *a3700_spi;
+	u32 cause;
+
+	a3700_spi = spi_master_get_devdata(master);
+
+	/* Get interrupt causes */
+	cause = spireg_read(a3700_spi, A3700_SPI_INT_STAT_REG);
+
+	if (!cause || !(a3700_spi->wait_mask & cause))
+		return IRQ_NONE;
+
+	/* mask and acknowledge the SPI interrupts */
+	spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_INT_STAT_REG, cause);
+
+	/* Wake up the transfer */
+	complete(&a3700_spi->done);
+
+	return IRQ_HANDLED;
+}
+
+static bool a3700_spi_wait_completion(struct spi_device *spi)
+{
+	struct a3700_spi *a3700_spi;
+	unsigned int timeout;
+	unsigned int ctrl_reg;
+	unsigned long timeout_jiffies;
+
+	a3700_spi = spi_master_get_devdata(spi->master);
+
+	/* SPI interrupt is edge-triggered, which means an interrupt will
+	 * be generated only when detecting a specific status bit changed
+	 * from '0' to '1'. So when we start waiting for a interrupt, we
+	 * need to check status bit in control reg first, if it is already 1,
+	 * then we do not need to wait for interrupt
+	 */
+	ctrl_reg = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	if (a3700_spi->wait_mask & ctrl_reg)
+		return true;
+
+	reinit_completion(&a3700_spi->done);
+
+	spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG,
+		     a3700_spi->wait_mask);
+
+	timeout_jiffies = msecs_to_jiffies(A3700_SPI_TIMEOUT);
+	timeout = wait_for_completion_timeout(&a3700_spi->done,
+					      timeout_jiffies);
+
+	a3700_spi->wait_mask = 0;
+
+	if (timeout)
+		return true;
+
+	/* there might be the case that right after we checked the
+	 * status bits in this routine and before start to wait for
+	 * interrupt by wait_for_completion_timeout, the interrupt
+	 * happens, to avoid missing it we need to double check
+	 * status bits in control reg, if it is already 1, then
+	 * consider that we have the interrupt successfully and
+	 * return true.
+	 */
+	ctrl_reg = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	if (a3700_spi->wait_mask & ctrl_reg)
+		return true;
+
+	spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0);
+
+	/* Timeout was reached */
+	return false;
+}
+
+static bool a3700_spi_transfer_wait(struct spi_device *spi,
+				    unsigned int bit_mask)
+{
+	struct a3700_spi *a3700_spi;
+
+	a3700_spi = spi_master_get_devdata(spi->master);
+	a3700_spi->wait_mask = bit_mask;
+
+	return a3700_spi_wait_completion(spi);
+}
+
+static void a3700_spi_fifo_thres_set(struct a3700_spi *a3700_spi,
+				     unsigned int bytes)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val &= ~(A3700_SPI_FIFO_THRS_MASK << A3700_SPI_RFIFO_THRS_BIT);
+	val |= (bytes - 1) << A3700_SPI_RFIFO_THRS_BIT;
+	val &= ~(A3700_SPI_FIFO_THRS_MASK << A3700_SPI_WFIFO_THRS_BIT);
+	val |= (7 - bytes) << A3700_SPI_WFIFO_THRS_BIT;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_transfer_setup(struct spi_device *spi,
+				     struct spi_transfer *xfer)
+{
+	struct a3700_spi *a3700_spi;
+
+	a3700_spi = spi_master_get_devdata(spi->master);
+
+	a3700_spi_clock_set(a3700_spi, xfer->speed_hz);
+
+	/* Use 4 bytes long transfers. Each transfer method has its way to deal
+	 * with the remaining bytes for non 4-bytes aligned transfers.
+	 */
+	a3700_spi_bytelen_set(a3700_spi, 4);
+
+	/* Initialize the working buffers */
+	a3700_spi->tx_buf  = xfer->tx_buf;
+	a3700_spi->rx_buf  = xfer->rx_buf;
+	a3700_spi->buf_len = xfer->len;
+}
+
+static void a3700_spi_set_cs(struct spi_device *spi, bool enable)
+{
+	struct a3700_spi *a3700_spi = spi_master_get_devdata(spi->master);
+
+	if (!enable)
+		a3700_spi_activate_cs(a3700_spi, spi->chip_select);
+	else
+		a3700_spi_deactivate_cs(a3700_spi, spi->chip_select);
+}
+
+static void a3700_spi_header_set(struct a3700_spi *a3700_spi)
+{
+	unsigned int addr_cnt;
+	u32 val = 0;
+
+	/* Clear the header registers */
+	spireg_write(a3700_spi, A3700_SPI_IF_INST_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_IF_RMODE_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, 0);
+
+	/* Set header counters */
+	if (a3700_spi->tx_buf) {
+		/*
+		 * when tx data is not 4 bytes aligned, there will be unexpected
+		 * bytes out of SPI output register, since it always shifts out
+		 * as whole 4 bytes. This might cause incorrect transaction with
+		 * some devices. To avoid that, use SPI header count feature to
+		 * transfer up to 3 bytes of data first, and then make the rest
+		 * of data 4-byte aligned.
+		 */
+		addr_cnt = a3700_spi->buf_len % 4;
+		if (addr_cnt) {
+			val = (addr_cnt & A3700_SPI_ADDR_CNT_MASK)
+				<< A3700_SPI_ADDR_CNT_BIT;
+			spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, val);
+
+			/* Update the buffer length to be transferred */
+			a3700_spi->buf_len -= addr_cnt;
+
+			/* transfer 1~3 bytes through address count */
+			val = 0;
+			while (addr_cnt--) {
+				val = (val << 8) | a3700_spi->tx_buf[0];
+				a3700_spi->tx_buf++;
+			}
+			spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, val);
+		}
+	}
+}
+
+static int a3700_is_wfifo_full(struct a3700_spi *a3700_spi)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	return (val & A3700_SPI_WFIFO_FULL);
+}
+
+static int a3700_spi_fifo_write(struct a3700_spi *a3700_spi)
+{
+	u32 val;
+
+	while (!a3700_is_wfifo_full(a3700_spi) && a3700_spi->buf_len) {
+		val = *(u32 *)a3700_spi->tx_buf;
+		spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, val);
+		a3700_spi->buf_len -= 4;
+		a3700_spi->tx_buf += 4;
+	}
+
+	return 0;
+}
+
+static int a3700_is_rfifo_empty(struct a3700_spi *a3700_spi)
+{
+	u32 val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+
+	return (val & A3700_SPI_RFIFO_EMPTY);
+}
+
+static int a3700_spi_fifo_read(struct a3700_spi *a3700_spi)
+{
+	u32 val;
+
+	while (!a3700_is_rfifo_empty(a3700_spi) && a3700_spi->buf_len) {
+		val = spireg_read(a3700_spi, A3700_SPI_DATA_IN_REG);
+		if (a3700_spi->buf_len >= 4) {
+
+			memcpy(a3700_spi->rx_buf, &val, 4);
+
+			a3700_spi->buf_len -= 4;
+			a3700_spi->rx_buf += 4;
+		} else {
+			/*
+			 * When remain bytes is not larger than 4, we should
+			 * avoid memory overwriting and just write the left rx
+			 * buffer bytes.
+			 */
+			while (a3700_spi->buf_len) {
+				*a3700_spi->rx_buf = val & 0xff;
+				val >>= 8;
+
+				a3700_spi->buf_len--;
+				a3700_spi->rx_buf++;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static void a3700_spi_transfer_abort_fifo(struct a3700_spi *a3700_spi)
+{
+	int timeout = A3700_SPI_TIMEOUT;
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val |= A3700_SPI_XFER_STOP;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	while (--timeout) {
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		if (!(val & A3700_SPI_XFER_START))
+			break;
+		udelay(1);
+	}
+
+	a3700_spi_fifo_flush(a3700_spi);
+
+	val &= ~A3700_SPI_XFER_STOP;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static int a3700_spi_prepare_message(struct spi_master *master,
+				     struct spi_message *message)
+{
+	struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+	struct spi_device *spi = message->spi;
+	int ret;
+
+	ret = clk_enable(a3700_spi->clk);
+	if (ret) {
+		dev_err(&spi->dev, "failed to enable clk with error %d\n", ret);
+		return ret;
+	}
+
+	/* Flush the FIFOs */
+	ret = a3700_spi_fifo_flush(a3700_spi);
+	if (ret)
+		return ret;
+
+	a3700_spi_mode_set(a3700_spi, spi->mode);
+
+	return 0;
+}
+
+static int a3700_spi_transfer_one_fifo(struct spi_master *master,
+				  struct spi_device *spi,
+				  struct spi_transfer *xfer)
+{
+	struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+	int ret = 0, timeout = A3700_SPI_TIMEOUT;
+	unsigned int nbits = 0, byte_len;
+	u32 val;
+
+	/* Make sure we use FIFO mode */
+	a3700_spi_fifo_mode_set(a3700_spi, true);
+
+	/* Configure FIFO thresholds */
+	byte_len = xfer->bits_per_word >> 3;
+	a3700_spi_fifo_thres_set(a3700_spi, byte_len);
+
+	if (xfer->tx_buf)
+		nbits = xfer->tx_nbits;
+	else if (xfer->rx_buf)
+		nbits = xfer->rx_nbits;
+
+	a3700_spi_pin_mode_set(a3700_spi, nbits, xfer->rx_buf ? true : false);
+
+	/* Flush the FIFOs */
+	a3700_spi_fifo_flush(a3700_spi);
+
+	/* Transfer first bytes of data when buffer is not 4-byte aligned */
+	a3700_spi_header_set(a3700_spi);
+
+	if (xfer->rx_buf) {
+		/* Clear WFIFO, since it's last 2 bytes are shifted out during
+		 * a read operation
+		 */
+		spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, 0);
+
+		/* Set read data length */
+		spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG,
+			     a3700_spi->buf_len);
+		/* Start READ transfer */
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		val &= ~A3700_SPI_RW_EN;
+		val |= A3700_SPI_XFER_START;
+		spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+	} else if (xfer->tx_buf) {
+		/* Start Write transfer */
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		val |= (A3700_SPI_XFER_START | A3700_SPI_RW_EN);
+		spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+		/*
+		 * If there are data to be written to the SPI device, xmit_data
+		 * flag is set true; otherwise the instruction in SPI_INSTR does
+		 * not require data to be written to the SPI device, then
+		 * xmit_data flag is set false.
+		 */
+		a3700_spi->xmit_data = (a3700_spi->buf_len != 0);
+	}
+
+	while (a3700_spi->buf_len) {
+		if (a3700_spi->tx_buf) {
+			/* Wait wfifo ready */
+			if (!a3700_spi_transfer_wait(spi,
+						     A3700_SPI_WFIFO_RDY)) {
+				dev_err(&spi->dev,
+					"wait wfifo ready timed out\n");
+				ret = -ETIMEDOUT;
+				goto error;
+			}
+			/* Fill up the wfifo */
+			ret = a3700_spi_fifo_write(a3700_spi);
+			if (ret)
+				goto error;
+		} else if (a3700_spi->rx_buf) {
+			/* Wait rfifo ready */
+			if (!a3700_spi_transfer_wait(spi,
+						     A3700_SPI_RFIFO_RDY)) {
+				dev_err(&spi->dev,
+					"wait rfifo ready timed out\n");
+				ret = -ETIMEDOUT;
+				goto error;
+			}
+			/* Drain out the rfifo */
+			ret = a3700_spi_fifo_read(a3700_spi);
+			if (ret)
+				goto error;
+		}
+	}
+
+	/*
+	 * Stop a write transfer in fifo mode:
+	 *	- wait all the bytes in wfifo to be shifted out
+	 *	 - set XFER_STOP bit
+	 *	- wait XFER_START bit clear
+	 *	- clear XFER_STOP bit
+	 * Stop a read transfer in fifo mode:
+	 *	- the hardware is to reset the XFER_START bit
+	 *	   after the number of bytes indicated in DIN_CNT
+	 *	   register
+	 *	- just wait XFER_START bit clear
+	 */
+	if (a3700_spi->tx_buf) {
+		if (a3700_spi->xmit_data) {
+			/*
+			 * If there are data written to the SPI device, wait
+			 * until SPI_WFIFO_EMPTY is 1 to wait for all data to
+			 * transfer out of write FIFO.
+			 */
+			if (!a3700_spi_transfer_wait(spi,
+						     A3700_SPI_WFIFO_EMPTY)) {
+				dev_err(&spi->dev, "wait wfifo empty timed out\n");
+				return -ETIMEDOUT;
+			}
+		}
+
+		if (!a3700_spi_transfer_wait(spi, A3700_SPI_XFER_RDY)) {
+			dev_err(&spi->dev, "wait xfer ready timed out\n");
+			return -ETIMEDOUT;
+		}
+
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		val |= A3700_SPI_XFER_STOP;
+		spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+	}
+
+	while (--timeout) {
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		if (!(val & A3700_SPI_XFER_START))
+			break;
+		udelay(1);
+	}
+
+	if (timeout == 0) {
+		dev_err(&spi->dev, "wait transfer start clear timed out\n");
+		ret = -ETIMEDOUT;
+		goto error;
+	}
+
+	val &= ~A3700_SPI_XFER_STOP;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+	goto out;
+
+error:
+	a3700_spi_transfer_abort_fifo(a3700_spi);
+out:
+	spi_finalize_current_transfer(master);
+
+	return ret;
+}
+
+static int a3700_spi_transfer_one_full_duplex(struct spi_master *master,
+				  struct spi_device *spi,
+				  struct spi_transfer *xfer)
+{
+	struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+	u32 val;
+
+	/* Disable FIFO mode */
+	a3700_spi_fifo_mode_set(a3700_spi, false);
+
+	while (a3700_spi->buf_len) {
+
+		/* When we have less than 4 bytes to transfer, switch to 1 byte
+		 * mode. This is reset after each transfer
+		 */
+		if (a3700_spi->buf_len < 4)
+			a3700_spi_bytelen_set(a3700_spi, 1);
+
+		if (a3700_spi->byte_len == 1)
+			val = *a3700_spi->tx_buf;
+		else
+			val = *(u32 *)a3700_spi->tx_buf;
+
+		spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, val);
+
+		/* Wait for all the data to be shifted in / out */
+		while (!(spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG) &
+				A3700_SPI_XFER_DONE))
+			cpu_relax();
+
+		val = spireg_read(a3700_spi, A3700_SPI_DATA_IN_REG);
+
+		memcpy(a3700_spi->rx_buf, &val, a3700_spi->byte_len);
+
+		a3700_spi->buf_len -= a3700_spi->byte_len;
+		a3700_spi->tx_buf += a3700_spi->byte_len;
+		a3700_spi->rx_buf += a3700_spi->byte_len;
+
+	}
+
+	spi_finalize_current_transfer(master);
+
+	return 0;
+}
+
+static int a3700_spi_transfer_one(struct spi_master *master,
+				  struct spi_device *spi,
+				  struct spi_transfer *xfer)
+{
+	a3700_spi_transfer_setup(spi, xfer);
+
+	if (xfer->tx_buf && xfer->rx_buf)
+		return a3700_spi_transfer_one_full_duplex(master, spi, xfer);
+
+	return a3700_spi_transfer_one_fifo(master, spi, xfer);
+}
+
+static int a3700_spi_unprepare_message(struct spi_master *master,
+				       struct spi_message *message)
+{
+	struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+
+	clk_disable(a3700_spi->clk);
+
+	return 0;
+}
+
+static const struct of_device_id a3700_spi_dt_ids[] = {
+	{ .compatible = "marvell,armada-3700-spi", .data = NULL },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, a3700_spi_dt_ids);
+
+static int a3700_spi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *of_node = dev->of_node;
+	struct resource *res;
+	struct spi_master *master;
+	struct a3700_spi *spi;
+	u32 num_cs = 0;
+	int irq, ret = 0;
+
+	master = spi_alloc_master(dev, sizeof(*spi));
+	if (!master) {
+		dev_err(dev, "master allocation failed\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (of_property_read_u32(of_node, "num-cs", &num_cs)) {
+		dev_err(dev, "could not find num-cs\n");
+		ret = -ENXIO;
+		goto error;
+	}
+
+	master->bus_num = pdev->id;
+	master->dev.of_node = of_node;
+	master->mode_bits = SPI_MODE_3;
+	master->num_chipselect = num_cs;
+	master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(32);
+	master->prepare_message =  a3700_spi_prepare_message;
+	master->transfer_one = a3700_spi_transfer_one;
+	master->unprepare_message = a3700_spi_unprepare_message;
+	master->set_cs = a3700_spi_set_cs;
+	master->mode_bits |= (SPI_RX_DUAL | SPI_TX_DUAL |
+			      SPI_RX_QUAD | SPI_TX_QUAD);
+
+	platform_set_drvdata(pdev, master);
+
+	spi = spi_master_get_devdata(master);
+	memset(spi, 0, sizeof(struct a3700_spi));
+
+	spi->master = master;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	spi->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(spi->base)) {
+		ret = PTR_ERR(spi->base);
+		goto error;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev, "could not get irq: %d\n", irq);
+		ret = -ENXIO;
+		goto error;
+	}
+	spi->irq = irq;
+
+	init_completion(&spi->done);
+
+	spi->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(spi->clk)) {
+		dev_err(dev, "could not find clk: %ld\n", PTR_ERR(spi->clk));
+		goto error;
+	}
+
+	ret = clk_prepare(spi->clk);
+	if (ret) {
+		dev_err(dev, "could not prepare clk: %d\n", ret);
+		goto error;
+	}
+
+	master->max_speed_hz = min_t(unsigned long, A3700_SPI_MAX_SPEED_HZ,
+					clk_get_rate(spi->clk));
+	master->min_speed_hz = DIV_ROUND_UP(clk_get_rate(spi->clk),
+						A3700_SPI_MAX_PRESCALE);
+
+	ret = a3700_spi_init(spi);
+	if (ret)
+		goto error_clk;
+
+	ret = devm_request_irq(dev, spi->irq, a3700_spi_interrupt, 0,
+			       dev_name(dev), master);
+	if (ret) {
+		dev_err(dev, "could not request IRQ: %d\n", ret);
+		goto error_clk;
+	}
+
+	ret = devm_spi_register_master(dev, master);
+	if (ret) {
+		dev_err(dev, "Failed to register master\n");
+		goto error_clk;
+	}
+
+	return 0;
+
+error_clk:
+	clk_unprepare(spi->clk);
+error:
+	spi_master_put(master);
+out:
+	return ret;
+}
+
+static int a3700_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = platform_get_drvdata(pdev);
+	struct a3700_spi *spi = spi_master_get_devdata(master);
+
+	clk_unprepare(spi->clk);
+
+	return 0;
+}
+
+static struct platform_driver a3700_spi_driver = {
+	.driver = {
+		.name	= DRIVER_NAME,
+		.of_match_table = of_match_ptr(a3700_spi_dt_ids),
+	},
+	.probe		= a3700_spi_probe,
+	.remove		= a3700_spi_remove,
+};
+
+module_platform_driver(a3700_spi_driver);
+
+MODULE_DESCRIPTION("Armada-3700 SPI driver");
+MODULE_AUTHOR("Wilson Ding <dingwei@marvell.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);