Applied "spi: stm32: add support for STM32F4" to the spi tree

[Mark Brown <broonie@xxxxxxxxxx>]

The patch

   spi: stm32: add support for STM32F4

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 00505edf95115707d91afd2685993b98daa93f15 Mon Sep 17 00:00:00 2001
From: Cezary Gapinski <cezary.gapinski@xxxxxxxxx>
Date: Mon, 24 Dec 2018 23:00:38 +0100
Subject: [PATCH] spi: stm32: add support for STM32F4

Add routines, registers & bitfield definition. Also baud rate divisor
definitions for STM32F4 SPI. This version supports full-duplex,
simplex TX and half-duplex TX communication with 8 or 16-bit per word.
DMA capability is optionally supported for transfer longer than 16 bytes.
For transfer less than 16 bytes frames can be send in discontinuous mode.

Signed-off-by: Cezary Gapinski <cezary.gapinski@xxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 drivers/spi/spi-stm32.c | 489 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 482 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 8b10074cc75f..4186ed20d796 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -20,6 +20,59 @@
 
 #define DRIVER_NAME "spi_stm32"
 
+/* STM32F4 SPI registers */
+#define STM32F4_SPI_CR1			0x00
+#define STM32F4_SPI_CR2			0x04
+#define STM32F4_SPI_SR			0x08
+#define STM32F4_SPI_DR			0x0C
+#define STM32F4_SPI_I2SCFGR		0x1C
+
+/* STM32F4_SPI_CR1 bit fields */
+#define STM32F4_SPI_CR1_CPHA		BIT(0)
+#define STM32F4_SPI_CR1_CPOL		BIT(1)
+#define STM32F4_SPI_CR1_MSTR		BIT(2)
+#define STM32F4_SPI_CR1_BR_SHIFT	3
+#define STM32F4_SPI_CR1_BR		GENMASK(5, 3)
+#define STM32F4_SPI_CR1_SPE		BIT(6)
+#define STM32F4_SPI_CR1_LSBFRST		BIT(7)
+#define STM32F4_SPI_CR1_SSI		BIT(8)
+#define STM32F4_SPI_CR1_SSM		BIT(9)
+#define STM32F4_SPI_CR1_RXONLY		BIT(10)
+#define STM32F4_SPI_CR1_DFF		BIT(11)
+#define STM32F4_SPI_CR1_CRCNEXT		BIT(12)
+#define STM32F4_SPI_CR1_CRCEN		BIT(13)
+#define STM32F4_SPI_CR1_BIDIOE		BIT(14)
+#define STM32F4_SPI_CR1_BIDIMODE	BIT(15)
+#define STM32F4_SPI_CR1_BR_MIN		0
+#define STM32F4_SPI_CR1_BR_MAX		(GENMASK(5, 3) >> 3)
+
+/* STM32F4_SPI_CR2 bit fields */
+#define STM32F4_SPI_CR2_RXDMAEN		BIT(0)
+#define STM32F4_SPI_CR2_TXDMAEN		BIT(1)
+#define STM32F4_SPI_CR2_SSOE		BIT(2)
+#define STM32F4_SPI_CR2_FRF		BIT(4)
+#define STM32F4_SPI_CR2_ERRIE		BIT(5)
+#define STM32F4_SPI_CR2_RXNEIE		BIT(6)
+#define STM32F4_SPI_CR2_TXEIE		BIT(7)
+
+/* STM32F4_SPI_SR bit fields */
+#define STM32F4_SPI_SR_RXNE		BIT(0)
+#define STM32F4_SPI_SR_TXE		BIT(1)
+#define STM32F4_SPI_SR_CHSIDE		BIT(2)
+#define STM32F4_SPI_SR_UDR		BIT(3)
+#define STM32F4_SPI_SR_CRCERR		BIT(4)
+#define STM32F4_SPI_SR_MODF		BIT(5)
+#define STM32F4_SPI_SR_OVR		BIT(6)
+#define STM32F4_SPI_SR_BSY		BIT(7)
+#define STM32F4_SPI_SR_FRE		BIT(8)
+
+/* STM32F4_SPI_I2SCFGR bit fields */
+#define STM32F4_SPI_I2SCFGR_I2SMOD	BIT(11)
+
+/* STM32F4 SPI Baud Rate min/max divisor */
+#define STM32F4_SPI_BR_DIV_MIN		(2 << STM32F4_SPI_CR1_BR_MIN)
+#define STM32F4_SPI_BR_DIV_MAX		(2 << STM32F4_SPI_CR1_BR_MAX)
+
 /* STM32H7 SPI registers */
 #define STM32H7_SPI_CR1			0x00
 #define STM32H7_SPI_CR2			0x04
@@ -116,6 +169,12 @@
 
 #define SPI_1HZ_NS		1000000000
 
+/*
+ * use PIO for small transfers, avoiding DMA setup/teardown overhead for drivers
+ * without fifo buffers.
+ */
+#define SPI_DMA_MIN_BYTES	16
+
 /**
  * stm32_spi_reg - stm32 SPI register & bitfield desc
  * @reg:		register offset
@@ -257,6 +316,21 @@ struct stm32_spi {
 	dma_addr_t phys_addr;
 };
 
+static const struct stm32_spi_regspec stm32f4_spi_regspec = {
+	.en = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_SPE },
+
+	.dma_rx_en = { STM32F4_SPI_CR2, STM32F4_SPI_CR2_RXDMAEN },
+	.dma_tx_en = { STM32F4_SPI_CR2, STM32F4_SPI_CR2_TXDMAEN },
+
+	.cpol = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_CPOL },
+	.cpha = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_CPHA },
+	.lsb_first = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_LSBFRST },
+	.br = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_BR, STM32F4_SPI_CR1_BR_SHIFT },
+
+	.rx = { STM32F4_SPI_DR },
+	.tx = { STM32F4_SPI_DR },
+};
+
 static const struct stm32_spi_regspec stm32h7_spi_regspec = {
 	/* SPI data transfer is enabled but spi_ker_ck is idle.
 	 * CFG1 and CFG2 registers are write protected when SPE is enabled.
@@ -315,6 +389,16 @@ static int stm32h7_spi_get_fifo_size(struct stm32_spi *spi)
 	return count;
 }
 
+/**
+ * stm32f4_spi_get_bpw_mask - Return bits per word mask
+ * @spi: pointer to the spi controller data structure
+ */
+static int stm32f4_spi_get_bpw_mask(struct stm32_spi *spi)
+{
+	dev_dbg(spi->dev, "8-bit or 16-bit data frame supported\n");
+	return SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
+}
+
 /**
  * stm32h7_spi_get_bpw_mask - Return bits per word mask
  * @spi: pointer to the spi controller data structure
@@ -408,6 +492,35 @@ static u32 stm32h7_spi_prepare_fthlv(struct stm32_spi *spi)
 	return fthlv;
 }
 
+/**
+ * stm32f4_spi_write_tx - Write bytes to Transmit Data Register
+ * @spi: pointer to the spi controller data structure
+ *
+ * Read from tx_buf depends on remaining bytes to avoid to read beyond
+ * tx_buf end.
+ */
+static void stm32f4_spi_write_tx(struct stm32_spi *spi)
+{
+	if ((spi->tx_len > 0) && (readl_relaxed(spi->base + STM32F4_SPI_SR) &
+				  STM32F4_SPI_SR_TXE)) {
+		u32 offs = spi->cur_xferlen - spi->tx_len;
+
+		if (spi->cur_bpw == 16) {
+			const u16 *tx_buf16 = (const u16 *)(spi->tx_buf + offs);
+
+			writew_relaxed(*tx_buf16, spi->base + STM32F4_SPI_DR);
+			spi->tx_len -= sizeof(u16);
+		} else {
+			const u8 *tx_buf8 = (const u8 *)(spi->tx_buf + offs);
+
+			writeb_relaxed(*tx_buf8, spi->base + STM32F4_SPI_DR);
+			spi->tx_len -= sizeof(u8);
+		}
+	}
+
+	dev_dbg(spi->dev, "%s: %d bytes left\n", __func__, spi->tx_len);
+}
+
 /**
  * stm32h7_spi_write_txfifo - Write bytes in Transmit Data Register
  * @spi: pointer to the spi controller data structure
@@ -443,6 +556,35 @@ static void stm32h7_spi_write_txfifo(struct stm32_spi *spi)
 	dev_dbg(spi->dev, "%s: %d bytes left\n", __func__, spi->tx_len);
 }
 
+/**
+ * stm32f4_spi_read_rx - Read bytes from Receive Data Register
+ * @spi: pointer to the spi controller data structure
+ *
+ * Write in rx_buf depends on remaining bytes to avoid to write beyond
+ * rx_buf end.
+ */
+static void stm32f4_spi_read_rx(struct stm32_spi *spi)
+{
+	if ((spi->rx_len > 0) && (readl_relaxed(spi->base + STM32F4_SPI_SR) &
+				  STM32F4_SPI_SR_RXNE)) {
+		u32 offs = spi->cur_xferlen - spi->rx_len;
+
+		if (spi->cur_bpw == 16) {
+			u16 *rx_buf16 = (u16 *)(spi->rx_buf + offs);
+
+			*rx_buf16 = readw_relaxed(spi->base + STM32F4_SPI_DR);
+			spi->rx_len -= sizeof(u16);
+		} else {
+			u8 *rx_buf8 = (u8 *)(spi->rx_buf + offs);
+
+			*rx_buf8 = readb_relaxed(spi->base + STM32F4_SPI_DR);
+			spi->rx_len -= sizeof(u8);
+		}
+	}
+
+	dev_dbg(spi->dev, "%s: %d bytes left\n", __func__, spi->rx_len);
+}
+
 /**
  * stm32h7_spi_read_rxfifo - Read bytes in Receive Data Register
  * @spi: pointer to the spi controller data structure
@@ -501,6 +643,54 @@ static void stm32_spi_enable(struct stm32_spi *spi)
 			   spi->cfg->regs->en.mask);
 }
 
+/**
+ * stm32f4_spi_disable - Disable SPI controller
+ * @spi: pointer to the spi controller data structure
+ */
+static void stm32f4_spi_disable(struct stm32_spi *spi)
+{
+	unsigned long flags;
+	u32 sr;
+
+	dev_dbg(spi->dev, "disable controller\n");
+
+	spin_lock_irqsave(&spi->lock, flags);
+
+	if (!(readl_relaxed(spi->base + STM32F4_SPI_CR1) &
+	      STM32F4_SPI_CR1_SPE)) {
+		spin_unlock_irqrestore(&spi->lock, flags);
+		return;
+	}
+
+	/* Disable interrupts */
+	stm32_spi_clr_bits(spi, STM32F4_SPI_CR2, STM32F4_SPI_CR2_TXEIE |
+						 STM32F4_SPI_CR2_RXNEIE |
+						 STM32F4_SPI_CR2_ERRIE);
+
+	/* Wait until BSY = 0 */
+	if (readl_relaxed_poll_timeout_atomic(spi->base + STM32F4_SPI_SR,
+					      sr, !(sr & STM32F4_SPI_SR_BSY),
+					      10, 100000) < 0) {
+		dev_warn(spi->dev, "disabling condition timeout\n");
+	}
+
+	if (spi->cur_usedma && spi->dma_tx)
+		dmaengine_terminate_all(spi->dma_tx);
+	if (spi->cur_usedma && spi->dma_rx)
+		dmaengine_terminate_all(spi->dma_rx);
+
+	stm32_spi_clr_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_SPE);
+
+	stm32_spi_clr_bits(spi, STM32F4_SPI_CR2, STM32F4_SPI_CR2_TXDMAEN |
+						 STM32F4_SPI_CR2_RXDMAEN);
+
+	/* Sequence to clear OVR flag */
+	readl_relaxed(spi->base + STM32F4_SPI_DR);
+	readl_relaxed(spi->base + STM32F4_SPI_SR);
+
+	spin_unlock_irqrestore(&spi->lock, flags);
+}
+
 /**
  * stm32h7_spi_disable - Disable SPI controller
  * @spi: pointer to the spi controller data structure
@@ -568,18 +758,128 @@ static void stm32h7_spi_disable(struct stm32_spi *spi)
 /**
  * stm32_spi_can_dma - Determine if the transfer is eligible for DMA use
  *
- * If the current transfer size is greater than fifo size, use DMA.
+ * If driver has fifo and the current transfer size is greater than fifo size,
+ * use DMA. Otherwise use DMA for transfer longer than defined DMA min bytes.
  */
 static bool stm32_spi_can_dma(struct spi_master *master,
 			      struct spi_device *spi_dev,
 			      struct spi_transfer *transfer)
 {
+	unsigned int dma_size;
 	struct stm32_spi *spi = spi_master_get_devdata(master);
 
+	if (spi->cfg->has_fifo)
+		dma_size = spi->fifo_size;
+	else
+		dma_size = SPI_DMA_MIN_BYTES;
+
 	dev_dbg(spi->dev, "%s: %s\n", __func__,
-		(transfer->len > spi->fifo_size) ? "true" : "false");
+		(transfer->len > dma_size) ? "true" : "false");
+
+	return (transfer->len > dma_size);
+}
+
+/**
+ * stm32f4_spi_irq_event - Interrupt handler for SPI controller events
+ * @irq: interrupt line
+ * @dev_id: SPI controller master interface
+ */
+static irqreturn_t stm32f4_spi_irq_event(int irq, void *dev_id)
+{
+	struct spi_master *master = dev_id;
+	struct stm32_spi *spi = spi_master_get_devdata(master);
+	u32 sr, mask = 0;
+	unsigned long flags;
+	bool end = false;
+
+	spin_lock_irqsave(&spi->lock, flags);
+
+	sr = readl_relaxed(spi->base + STM32F4_SPI_SR);
+	/*
+	 * BSY flag is not handled in interrupt but it is normal behavior when
+	 * this flag is set.
+	 */
+	sr &= ~STM32F4_SPI_SR_BSY;
+
+	if (!spi->cur_usedma && (spi->cur_comm == SPI_SIMPLEX_TX ||
+				 spi->cur_comm == SPI_3WIRE_TX)) {
+		/* OVR flag shouldn't be handled for TX only mode */
+		sr &= ~STM32F4_SPI_SR_OVR | STM32F4_SPI_SR_RXNE;
+		mask |= STM32F4_SPI_SR_TXE;
+	}
+
+	if (!spi->cur_usedma && spi->cur_comm == SPI_FULL_DUPLEX) {
+		/* TXE flag is set and is handled when RXNE flag occurs */
+		sr &= ~STM32F4_SPI_SR_TXE;
+		mask |= STM32F4_SPI_SR_RXNE | STM32F4_SPI_SR_OVR;
+	}
+
+	if (!(sr & mask)) {
+		dev_dbg(spi->dev, "spurious IT (sr=0x%08x)\n", sr);
+		spin_unlock_irqrestore(&spi->lock, flags);
+		return IRQ_NONE;
+	}
+
+	if (sr & STM32F4_SPI_SR_OVR) {
+		dev_warn(spi->dev, "Overrun: received value discarded\n");
+
+		/* Sequence to clear OVR flag */
+		readl_relaxed(spi->base + STM32F4_SPI_DR);
+		readl_relaxed(spi->base + STM32F4_SPI_SR);
+
+		/*
+		 * If overrun is detected, it means that something went wrong,
+		 * so stop the current transfer. Transfer can wait for next
+		 * RXNE but DR is already read and end never happens.
+		 */
+		end = true;
+		goto end_irq;
+	}
+
+	if (sr & STM32F4_SPI_SR_TXE) {
+		if (spi->tx_buf)
+			stm32f4_spi_write_tx(spi);
+		if (spi->tx_len == 0)
+			end = true;
+	}
+
+	if (sr & STM32F4_SPI_SR_RXNE) {
+		stm32f4_spi_read_rx(spi);
+		if (spi->rx_len == 0)
+			end = true;
+		else /* Load data for discontinuous mode */
+			stm32f4_spi_write_tx(spi);
+	}
+
+end_irq:
+	if (end) {
+		/* Immediately disable interrupts to do not generate new one */
+		stm32_spi_clr_bits(spi, STM32F4_SPI_CR2,
+					STM32F4_SPI_CR2_TXEIE |
+					STM32F4_SPI_CR2_RXNEIE |
+					STM32F4_SPI_CR2_ERRIE);
+		spin_unlock_irqrestore(&spi->lock, flags);
+		return IRQ_WAKE_THREAD;
+	}
+
+	spin_unlock_irqrestore(&spi->lock, flags);
+	return IRQ_HANDLED;
+}
+
+/**
+ * stm32f4_spi_irq_thread - Thread of interrupt handler for SPI controller
+ * @irq: interrupt line
+ * @dev_id: SPI controller master interface
+ */
+static irqreturn_t stm32f4_spi_irq_thread(int irq, void *dev_id)
+{
+	struct spi_master *master = dev_id;
+	struct stm32_spi *spi = spi_master_get_devdata(master);
+
+	spi_finalize_current_transfer(master);
+	stm32f4_spi_disable(spi);
 
-	return (transfer->len > spi->fifo_size);
+	return IRQ_HANDLED;
 }
 
 /**
@@ -748,6 +1048,34 @@ static int stm32_spi_prepare_msg(struct spi_master *master,
 	return 0;
 }
 
+/**
+ * stm32f4_spi_dma_tx_cb - dma callback
+ *
+ * DMA callback is called when the transfer is complete for DMA TX channel.
+ */
+static void stm32f4_spi_dma_tx_cb(void *data)
+{
+	struct stm32_spi *spi = data;
+
+	if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX) {
+		spi_finalize_current_transfer(spi->master);
+		stm32f4_spi_disable(spi);
+	}
+}
+
+/**
+ * stm32f4_spi_dma_rx_cb - dma callback
+ *
+ * DMA callback is called when the transfer is complete for DMA RX channel.
+ */
+static void stm32f4_spi_dma_rx_cb(void *data)
+{
+	struct stm32_spi *spi = data;
+
+	spi_finalize_current_transfer(spi->master);
+	stm32f4_spi_disable(spi);
+}
+
 /**
  * stm32h7_spi_dma_cb - dma callback
  *
@@ -790,11 +1118,15 @@ static void stm32_spi_dma_config(struct stm32_spi *spi,
 	else
 		buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
 
-	/* Valid for DMA Half or Full Fifo threshold */
-	if (spi->cur_fthlv == 2)
+	if (spi->cfg->has_fifo) {
+		/* Valid for DMA Half or Full Fifo threshold */
+		if (spi->cur_fthlv == 2)
+			maxburst = 1;
+		else
+			maxburst = spi->cur_fthlv;
+	} else {
 		maxburst = 1;
-	else
-		maxburst = spi->cur_fthlv;
+	}
 
 	memset(dma_conf, 0, sizeof(struct dma_slave_config));
 	dma_conf->direction = dir;
@@ -815,6 +1147,46 @@ static void stm32_spi_dma_config(struct stm32_spi *spi,
 	}
 }
 
+/**
+ * stm32f4_spi_transfer_one_irq - transfer a single spi_transfer using
+ *				  interrupts
+ *
+ * It must returns 0 if the transfer is finished or 1 if the transfer is still
+ * in progress.
+ */
+static int stm32f4_spi_transfer_one_irq(struct stm32_spi *spi)
+{
+	unsigned long flags;
+	u32 cr2 = 0;
+
+	/* Enable the interrupts relative to the current communication mode */
+	if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX) {
+		cr2 |= STM32F4_SPI_CR2_TXEIE;
+	} else if (spi->cur_comm == SPI_FULL_DUPLEX) {
+		/* In transmit-only mode, the OVR flag is set in the SR register
+		 * since the received data are never read. Therefore set OVR
+		 * interrupt only when rx buffer is available.
+		 */
+		cr2 |= STM32F4_SPI_CR2_RXNEIE | STM32F4_SPI_CR2_ERRIE;
+	} else {
+		return -EINVAL;
+	}
+
+	spin_lock_irqsave(&spi->lock, flags);
+
+	stm32_spi_set_bits(spi, STM32F4_SPI_CR2, cr2);
+
+	stm32_spi_enable(spi);
+
+	/* starting data transfer when buffer is loaded */
+	if (spi->tx_buf)
+		stm32f4_spi_write_tx(spi);
+
+	spin_unlock_irqrestore(&spi->lock, flags);
+
+	return 1;
+}
+
 /**
  * stm32h7_spi_transfer_one_irq - transfer a single spi_transfer using
  *				  interrupts
@@ -856,6 +1228,26 @@ static int stm32h7_spi_transfer_one_irq(struct stm32_spi *spi)
 	return 1;
 }
 
+/**
+ * stm32f4_spi_transfer_one_dma_start - Set SPI driver registers to start
+ *					transfer using DMA
+ */
+static void stm32f4_spi_transfer_one_dma_start(struct stm32_spi *spi)
+{
+	/* In DMA mode end of transfer is handled by DMA TX or RX callback. */
+	if (spi->cur_comm == SPI_SIMPLEX_RX || spi->cur_comm == SPI_3WIRE_RX ||
+	    spi->cur_comm == SPI_FULL_DUPLEX) {
+		/*
+		 * In transmit-only mode, the OVR flag is set in the SR register
+		 * since the received data are never read. Therefore set OVR
+		 * interrupt only when rx buffer is available.
+		 */
+		stm32_spi_set_bits(spi, STM32F4_SPI_CR2, STM32F4_SPI_CR2_ERRIE);
+	}
+
+	stm32_spi_enable(spi);
+}
+
 /**
  * stm32h7_spi_transfer_one_dma_start - Set SPI driver registers to start
  *					transfer using DMA
@@ -976,6 +1368,18 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi,
 	return spi->cfg->transfer_one_irq(spi);
 }
 
+/**
+ * stm32f4_spi_set_bpw - Configure bits per word
+ * @spi: pointer to the spi controller data structure
+ */
+static void stm32f4_spi_set_bpw(struct stm32_spi *spi)
+{
+	if (spi->cur_bpw == 16)
+		stm32_spi_set_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_DFF);
+	else
+		stm32_spi_clr_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_DFF);
+}
+
 /**
  * stm32h7_spi_set_bpw - configure bits per word
  * @spi: pointer to the spi controller data structure
@@ -1053,6 +1457,28 @@ static unsigned int stm32_spi_communication_type(struct spi_device *spi_dev,
 	return type;
 }
 
+/**
+ * stm32f4_spi_set_mode - configure communication mode
+ * @spi: pointer to the spi controller data structure
+ * @comm_type: type of communication to configure
+ */
+static int stm32f4_spi_set_mode(struct stm32_spi *spi, unsigned int comm_type)
+{
+	if (comm_type == SPI_3WIRE_TX || comm_type == SPI_SIMPLEX_TX) {
+		stm32_spi_set_bits(spi, STM32F4_SPI_CR1,
+					STM32F4_SPI_CR1_BIDIMODE |
+					STM32F4_SPI_CR1_BIDIOE);
+	} else if (comm_type == SPI_FULL_DUPLEX) {
+		stm32_spi_clr_bits(spi, STM32F4_SPI_CR1,
+					STM32F4_SPI_CR1_BIDIMODE |
+					STM32F4_SPI_CR1_BIDIOE);
+	} else {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /**
  * stm32h7_spi_set_mode - configure communication mode
  * @spi: pointer to the spi controller data structure
@@ -1267,6 +1693,36 @@ static int stm32_spi_unprepare_msg(struct spi_master *master,
 	return 0;
 }
 
+/**
+ * stm32f4_spi_config - Configure SPI controller as SPI master
+ */
+static int stm32f4_spi_config(struct stm32_spi *spi)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&spi->lock, flags);
+
+	/* Ensure I2SMOD bit is kept cleared */
+	stm32_spi_clr_bits(spi, STM32F4_SPI_I2SCFGR,
+			   STM32F4_SPI_I2SCFGR_I2SMOD);
+
+	/*
+	 * - SS input value high
+	 * - transmitter half duplex direction
+	 * - Set the master mode (default Motorola mode)
+	 * - Consider 1 master/n slaves configuration and
+	 *   SS input value is determined by the SSI bit
+	 */
+	stm32_spi_set_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_SSI |
+						 STM32F4_SPI_CR1_BIDIOE |
+						 STM32F4_SPI_CR1_MSTR |
+						 STM32F4_SPI_CR1_SSM);
+
+	spin_unlock_irqrestore(&spi->lock, flags);
+
+	return 0;
+}
+
 /**
  * stm32h7_spi_config - Configure SPI controller as SPI master
  */
@@ -1304,6 +1760,24 @@ static int stm32h7_spi_config(struct stm32_spi *spi)
 	return 0;
 }
 
+static const struct stm32_spi_cfg stm32f4_spi_cfg = {
+	.regs = &stm32f4_spi_regspec,
+	.get_bpw_mask = stm32f4_spi_get_bpw_mask,
+	.disable = stm32f4_spi_disable,
+	.config = stm32f4_spi_config,
+	.set_bpw = stm32f4_spi_set_bpw,
+	.set_mode = stm32f4_spi_set_mode,
+	.transfer_one_dma_start = stm32f4_spi_transfer_one_dma_start,
+	.dma_tx_cb = stm32f4_spi_dma_tx_cb,
+	.dma_rx_cb = stm32f4_spi_dma_rx_cb,
+	.transfer_one_irq = stm32f4_spi_transfer_one_irq,
+	.irq_handler_event = stm32f4_spi_irq_event,
+	.irq_handler_thread = stm32f4_spi_irq_thread,
+	.baud_rate_div_min = STM32F4_SPI_BR_DIV_MIN,
+	.baud_rate_div_max = STM32F4_SPI_BR_DIV_MAX,
+	.has_fifo = false,
+};
+
 static const struct stm32_spi_cfg stm32h7_spi_cfg = {
 	.regs = &stm32h7_spi_regspec,
 	.get_fifo_size = stm32h7_spi_get_fifo_size,
@@ -1326,6 +1800,7 @@ static const struct stm32_spi_cfg stm32h7_spi_cfg = {
 
 static const struct of_device_id stm32_spi_of_match[] = {
 	{ .compatible = "st,stm32h7-spi", .data = (void *)&stm32h7_spi_cfg },
+	{ .compatible = "st,stm32f4-spi", .data = (void *)&stm32f4_spi_cfg },
 	{},
 };
 MODULE_DEVICE_TABLE(of, stm32_spi_of_match);
-- 
2.20.1