spi: Fixes for v6.11

The bulk of this is a series of fixes for the microchip-core driver
 mostly originating from one of their customers, I also applied an
 additional patch adding support for controlling the word size which came
 along with it since it's still the merge window and clearly had a bunch
 of fairly thorough testing.
 
 We also have a fix for the compatible used to bind spidev to the
 BH2228FV.
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Merge tag 'spi-fix-v6.11-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi

Pull spi fixes from Mark Brown:
 "The bulk of this is a series of fixes for the microchip-core driver
  mostly originating from one of their customers, I also applied an
  additional patch adding support for controlling the word size which
  came along with it since it's still the merge window and clearly had a
  bunch of fairly thorough testing.

  We also have a fix for the compatible used to bind spidev to the
  BH2228FV"

* tag 'spi-fix-v6.11-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: spidev: add correct compatible for Rohm BH2228FV
  dt-bindings: trivial-devices: fix Rohm BH2228FV compatible string
  spi: microchip-core: add support for word sizes of 1 to 32 bits
  spi: microchip-core: ensure TX and RX FIFOs are empty at start of a transfer
  spi: microchip-core: fix init function not setting the master and motorola modes
  spi: microchip-core: only disable SPI controller when register value change requires it
  spi: microchip-core: defer asserting chip select until just before write to TX FIFO
  spi: microchip-core: fix the issues in the isr

Documentation/devicetree/bindings/trivial-devices.yaml

@@ -328,7 +328,9 @@ properties:
           - renesas,hs3001
             # Renesas ISL29501 time-of-flight sensor
           - renesas,isl29501
-            # Rohm DH2228FV
+            # Rohm BH2228FV 8 channel DAC
+          - rohm,bh2228fv
+            # Rohm DH2228FV - This device does not exist, use rohm,bh2228fv instead.
           - rohm,dh2228fv
             # S524AD0XF1 (128K/256K-bit Serial EEPROM for Low Power)
           - samsung,24ad0xd1

drivers/spi/spi-microchip-core.c

@@ -75,6 +75,7 @@
 
 #define REG_CONTROL		(0x00)
 #define REG_FRAME_SIZE		(0x04)
+#define  FRAME_SIZE_MASK	GENMASK(5, 0)
 #define REG_STATUS		(0x08)
 #define REG_INT_CLEAR		(0x0c)
 #define REG_RX_DATA		(0x10)
@@ -89,6 +90,9 @@
 #define REG_RIS			(0x24)
 #define REG_CONTROL2		(0x28)
 #define REG_COMMAND		(0x2c)
+#define  COMMAND_CLRFRAMECNT	BIT(4)
+#define  COMMAND_TXFIFORST		BIT(3)
+#define  COMMAND_RXFIFORST		BIT(2)
 #define REG_PKTSIZE		(0x30)
 #define REG_CMD_SIZE		(0x34)
 #define REG_HWSTATUS		(0x38)
@@ -103,10 +107,11 @@ struct mchp_corespi {
 	u8 *rx_buf;
 	u32 clk_gen; /* divider for spi output clock generated by the controller */
 	u32 clk_mode;
+	u32 pending_slave_select;
 	int irq;
 	int tx_len;
 	int rx_len;
-	int pending;
+	int n_bytes;
 };
 
 static inline u32 mchp_corespi_read(struct mchp_corespi *spi, unsigned int reg)
@@ -130,113 +135,126 @@ static inline void mchp_corespi_disable(struct mchp_corespi *spi)
 
 static inline void mchp_corespi_read_fifo(struct mchp_corespi *spi)
 {
-	u8 data;
+	while (spi->rx_len >= spi->n_bytes && !(mchp_corespi_read(spi, REG_STATUS) & STATUS_RXFIFO_EMPTY)) {
-	int fifo_max, i = 0;
+		u32 data = mchp_corespi_read(spi, REG_RX_DATA);
 
-	fifo_max = min(spi->rx_len, FIFO_DEPTH);
+		spi->rx_len -= spi->n_bytes;
 
-	while ((i < fifo_max) && !(mchp_corespi_read(spi, REG_STATUS) & STATUS_RXFIFO_EMPTY)) {
+		if (!spi->rx_buf)
-		data = mchp_corespi_read(spi, REG_RX_DATA);
+			continue;
 
-		if (spi->rx_buf)
+		if (spi->n_bytes == 4)
-			*spi->rx_buf++ = data;
+			*((u32 *)spi->rx_buf) = data;
-		i++;
+		else if (spi->n_bytes == 2)
+			*((u16 *)spi->rx_buf) = data;
+		else
+			*spi->rx_buf = data;
+
+		spi->rx_buf += spi->n_bytes;
 	}
-	spi->rx_len -= i;
-	spi->pending -= i;
 }
 
 static void mchp_corespi_enable_ints(struct mchp_corespi *spi)
 {
-	u32 control, mask = INT_ENABLE_MASK;
+	u32 control = mchp_corespi_read(spi, REG_CONTROL);
 
-	mchp_corespi_disable(spi);
+	control |= INT_ENABLE_MASK;
-
-	control = mchp_corespi_read(spi, REG_CONTROL);
-
-	control |= mask;
-	mchp_corespi_write(spi, REG_CONTROL, control);
-
-	control |= CONTROL_ENABLE;
 	mchp_corespi_write(spi, REG_CONTROL, control);
 }
 
 static void mchp_corespi_disable_ints(struct mchp_corespi *spi)
 {
-	u32 control, mask = INT_ENABLE_MASK;
+	u32 control = mchp_corespi_read(spi, REG_CONTROL);
 
-	mchp_corespi_disable(spi);
+	control &= ~INT_ENABLE_MASK;
-
-	control = mchp_corespi_read(spi, REG_CONTROL);
-	control &= ~mask;
-	mchp_corespi_write(spi, REG_CONTROL, control);
-
-	control |= CONTROL_ENABLE;
 	mchp_corespi_write(spi, REG_CONTROL, control);
 }
 
 static inline void mchp_corespi_set_xfer_size(struct mchp_corespi *spi, int len)
 {
 	u32 control;
-	u16 lenpart;
+	u32 lenpart;
+	u32 frames = mchp_corespi_read(spi, REG_FRAMESUP);
 
 	/*
-	 * Disable the SPI controller. Writes to transfer length have
+	 * Writing to FRAMECNT in REG_CONTROL will reset the frame count, taking
-	 * no effect when the controller is enabled.
+	 * a shortcut requires an explicit clear.
 	 */
-	mchp_corespi_disable(spi);
+	if (frames == len) {
+		mchp_corespi_write(spi, REG_COMMAND, COMMAND_CLRFRAMECNT);
+		return;
+	}
 
 	/*
 	 * The lower 16 bits of the frame count are stored in the control reg
 	 * for legacy reasons, but the upper 16 written to a different register:
 	 * FRAMESUP. While both the upper and lower bits can be *READ* from the
-	 * FRAMESUP register, writing to the lower 16 bits is a NOP
+	 * FRAMESUP register, writing to the lower 16 bits is (supposedly) a NOP.
+	 *
+	 * The driver used to disable the controller while modifying the frame
+	 * count, and mask off the lower 16 bits of len while writing to
+	 * FRAMES_UP. When the driver was changed to disable the controller as
+	 * infrequently as possible, it was discovered that the logic of
+	 * lenpart = len & 0xffff_0000
+	 * write(REG_FRAMESUP, lenpart)
+	 * would actually write zeros into the lower 16 bits on an mpfs250t-es,
+	 * despite documentation stating these bits were read-only.
+	 * Writing len unmasked into FRAMES_UP ensures those bits aren't zeroed
+	 * on an mpfs250t-es and will be a NOP for the lower 16 bits on hardware
+	 * that matches the documentation.
 	 */
 	lenpart = len & 0xffff;
-
 	control = mchp_corespi_read(spi, REG_CONTROL);
 	control &= ~CONTROL_FRAMECNT_MASK;
 	control |= lenpart << CONTROL_FRAMECNT_SHIFT;
 	mchp_corespi_write(spi, REG_CONTROL, control);
-
+	mchp_corespi_write(spi, REG_FRAMESUP, len);
-	lenpart = len & 0xffff0000;
-	mchp_corespi_write(spi, REG_FRAMESUP, lenpart);
-
-	control |= CONTROL_ENABLE;
-	mchp_corespi_write(spi, REG_CONTROL, control);
 }
 
 static inline void mchp_corespi_write_fifo(struct mchp_corespi *spi)
 {
-	u8 byte;
 	int fifo_max, i = 0;
 
-	fifo_max = min(spi->tx_len, FIFO_DEPTH);
+	fifo_max = DIV_ROUND_UP(min(spi->tx_len, FIFO_DEPTH), spi->n_bytes);
 	mchp_corespi_set_xfer_size(spi, fifo_max);
 
 	while ((i < fifo_max) && !(mchp_corespi_read(spi, REG_STATUS) & STATUS_TXFIFO_FULL)) {
-		byte = spi->tx_buf ? *spi->tx_buf++ : 0xaa;
+		u32 word;
-		mchp_corespi_write(spi, REG_TX_DATA, byte);
+
+		if (spi->n_bytes == 4)
+			word = spi->tx_buf ? *((u32 *)spi->tx_buf) : 0xaa;
+		else if (spi->n_bytes == 2)
+			word = spi->tx_buf ? *((u16 *)spi->tx_buf) : 0xaa;
+		else
+			word = spi->tx_buf ? *spi->tx_buf : 0xaa;
+
+		mchp_corespi_write(spi, REG_TX_DATA, word);
+		if (spi->tx_buf)
+			spi->tx_buf += spi->n_bytes;
 		i++;
 	}
 
-	spi->tx_len -= i;
+	spi->tx_len -= i * spi->n_bytes;
-	spi->pending += i;
 }
 
 static inline void mchp_corespi_set_framesize(struct mchp_corespi *spi, int bt)
 {
+	u32 frame_size = mchp_corespi_read(spi, REG_FRAME_SIZE);
 	u32 control;
 
+	if ((frame_size & FRAME_SIZE_MASK) == bt)
+		return;
+
 	/*
 	 * Disable the SPI controller. Writes to the frame size have
 	 * no effect when the controller is enabled.
 	 */
-	mchp_corespi_disable(spi);
+	control = mchp_corespi_read(spi, REG_CONTROL);
+	control &= ~CONTROL_ENABLE;
+	mchp_corespi_write(spi, REG_CONTROL, control);
 
 	mchp_corespi_write(spi, REG_FRAME_SIZE, bt);
 
-	control = mchp_corespi_read(spi, REG_CONTROL);
 	control |= CONTROL_ENABLE;
 	mchp_corespi_write(spi, REG_CONTROL, control);
 }
@@ -249,7 +267,17 @@ static void mchp_corespi_set_cs(struct spi_device *spi, bool disable)
 	reg = mchp_corespi_read(corespi, REG_SLAVE_SELECT);
 	reg &= ~BIT(spi_get_chipselect(spi, 0));
 	reg |= !disable << spi_get_chipselect(spi, 0);
+	corespi->pending_slave_select = reg;
 
+	/*
+	 * Only deassert chip select immediately. Writing to some registers
+	 * requires the controller to be disabled, which results in the
+	 * output pins being tristated and can cause the SCLK and MOSI lines
+	 * to transition. Therefore asserting the chip select is deferred
+	 * until just before writing to the TX FIFO, to ensure the device
+	 * doesn't see any spurious clock transitions whilst CS is enabled.
+	 */
+	if (((spi->mode & SPI_CS_HIGH) == 0) == disable)
 		mchp_corespi_write(corespi, REG_SLAVE_SELECT, reg);
 }
 
@@ -269,6 +297,7 @@ static int mchp_corespi_setup(struct spi_device *spi)
 	if (spi->mode & SPI_CS_HIGH) {
 		reg = mchp_corespi_read(corespi, REG_SLAVE_SELECT);
 		reg |= BIT(spi_get_chipselect(spi, 0));
+		corespi->pending_slave_select = reg;
 		mchp_corespi_write(corespi, REG_SLAVE_SELECT, reg);
 	}
 	return 0;
@@ -279,17 +308,13 @@ static void mchp_corespi_init(struct spi_controller *host, struct mchp_corespi *
 	unsigned long clk_hz;
 	u32 control = mchp_corespi_read(spi, REG_CONTROL);
 
-	control |= CONTROL_MASTER;
+	control &= ~CONTROL_ENABLE;
+	mchp_corespi_write(spi, REG_CONTROL, control);
 
+	control |= CONTROL_MASTER;
 	control &= ~CONTROL_MODE_MASK;
 	control |= MOTOROLA_MODE;
 
-	mchp_corespi_set_framesize(spi, DEFAULT_FRAMESIZE);
-
-	/* max. possible spi clock rate is the apb clock rate */
-	clk_hz = clk_get_rate(spi->clk);
-	host->max_speed_hz = clk_hz;
-
 	/*
 	 * The controller must be configured so that it doesn't remove Chip
 	 * Select until the entire message has been transferred, even if at
@@ -298,11 +323,16 @@ static void mchp_corespi_init(struct spi_controller *host, struct mchp_corespi *
 	 * BIGFIFO mode is also enabled, which sets the fifo depth to 32 frames
 	 * for the 8 bit transfers that this driver uses.
 	 */
-	control = mchp_corespi_read(spi, REG_CONTROL);
 	control |= CONTROL_SPS | CONTROL_BIGFIFO;
 
 	mchp_corespi_write(spi, REG_CONTROL, control);
 
+	mchp_corespi_set_framesize(spi, DEFAULT_FRAMESIZE);
+
+	/* max. possible spi clock rate is the apb clock rate */
+	clk_hz = clk_get_rate(spi->clk);
+	host->max_speed_hz = clk_hz;
+
 	mchp_corespi_enable_ints(spi);
 
 	/*
@@ -310,7 +340,8 @@ static void mchp_corespi_init(struct spi_controller *host, struct mchp_corespi *
 	 * select is relinquished to the hardware. SSELOUT is enabled too so we
 	 * can deal with active high targets.
 	 */
-	mchp_corespi_write(spi, REG_SLAVE_SELECT, SSELOUT | SSEL_DIRECT);
+	spi->pending_slave_select = SSELOUT | SSEL_DIRECT;
+	mchp_corespi_write(spi, REG_SLAVE_SELECT, spi->pending_slave_select);
 
 	control = mchp_corespi_read(spi, REG_CONTROL);
 
@@ -324,8 +355,6 @@ static inline void mchp_corespi_set_clk_gen(struct mchp_corespi *spi)
 {
 	u32 control;
 
-	mchp_corespi_disable(spi);
-
 	control = mchp_corespi_read(spi, REG_CONTROL);
 	if (spi->clk_mode)
 		control |= CONTROL_CLKMODE;
@@ -334,12 +363,12 @@ static inline void mchp_corespi_set_clk_gen(struct mchp_corespi *spi)
 
 	mchp_corespi_write(spi, REG_CLK_GEN, spi->clk_gen);
 	mchp_corespi_write(spi, REG_CONTROL, control);
-	mchp_corespi_write(spi, REG_CONTROL, control | CONTROL_ENABLE);
 }
 
 static inline void mchp_corespi_set_mode(struct mchp_corespi *spi, unsigned int mode)
 {
-	u32 control, mode_val;
+	u32 mode_val;
+	u32 control = mchp_corespi_read(spi, REG_CONTROL);
 
 	switch (mode & SPI_MODE_X_MASK) {
 	case SPI_MODE_0:
@@ -357,12 +386,13 @@ static inline void mchp_corespi_set_mode(struct mchp_corespi *spi, unsigned int
 	}
 
 	/*
-	 * Disable the SPI controller. Writes to the frame size have
+	 * Disable the SPI controller. Writes to the frame protocol have
 	 * no effect when the controller is enabled.
 	 */
-	mchp_corespi_disable(spi);
 
-	control = mchp_corespi_read(spi, REG_CONTROL);
+	control &= ~CONTROL_ENABLE;
+	mchp_corespi_write(spi, REG_CONTROL, control);
+
 	control &= ~(SPI_MODE_X_MASK << MODE_X_MASK_SHIFT);
 	control |= mode_val;
 
@@ -383,21 +413,18 @@ static irqreturn_t mchp_corespi_interrupt(int irq, void *dev_id)
 	if (intfield == 0)
 		return IRQ_NONE;
 
-	if (intfield & INT_TXDONE) {
+	if (intfield & INT_TXDONE)
 		mchp_corespi_write(spi, REG_INT_CLEAR, INT_TXDONE);
 
+	if (intfield & INT_RXRDY) {
+		mchp_corespi_write(spi, REG_INT_CLEAR, INT_RXRDY);
+
 		if (spi->rx_len)
 			mchp_corespi_read_fifo(spi);
-
-		if (spi->tx_len)
-			mchp_corespi_write_fifo(spi);
-
-		if (!spi->rx_len)
-			finalise = true;
 	}
 
-	if (intfield & INT_RXRDY)
+	if (!spi->rx_len && !spi->tx_len)
-		mchp_corespi_write(spi, REG_INT_CLEAR, INT_RXRDY);
+		finalise = true;
 
 	if (intfield & INT_RX_CHANNEL_OVERFLOW) {
 		mchp_corespi_write(spi, REG_INT_CLEAR, INT_RX_CHANNEL_OVERFLOW);
@@ -477,13 +504,17 @@ static int mchp_corespi_transfer_one(struct spi_controller *host,
 	spi->rx_buf = xfer->rx_buf;
 	spi->tx_len = xfer->len;
 	spi->rx_len = xfer->len;
-	spi->pending = 0;
+	spi->n_bytes = roundup_pow_of_two(DIV_ROUND_UP(xfer->bits_per_word, BITS_PER_BYTE));
 
-	mchp_corespi_set_xfer_size(spi, (spi->tx_len > FIFO_DEPTH)
+	mchp_corespi_set_framesize(spi, xfer->bits_per_word);
-				   ? FIFO_DEPTH : spi->tx_len);
 
-	if (spi->tx_len)
+	mchp_corespi_write(spi, REG_COMMAND, COMMAND_RXFIFORST | COMMAND_TXFIFORST);
+
+	mchp_corespi_write(spi, REG_SLAVE_SELECT, spi->pending_slave_select);
+
+	while (spi->tx_len)
 		mchp_corespi_write_fifo(spi);
+
 	return 1;
 }
 
@@ -493,7 +524,6 @@ static int mchp_corespi_prepare_message(struct spi_controller *host,
 	struct spi_device *spi_dev = msg->spi;
 	struct mchp_corespi *spi = spi_controller_get_devdata(host);
 
-	mchp_corespi_set_framesize(spi, DEFAULT_FRAMESIZE);
 	mchp_corespi_set_mode(spi, spi_dev->mode);
 
 	return 0;
@@ -521,7 +551,7 @@ static int mchp_corespi_probe(struct platform_device *pdev)
 	host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 	host->use_gpio_descriptors = true;
 	host->setup = mchp_corespi_setup;
-	host->bits_per_word_mask = SPI_BPW_MASK(8);
+	host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
 	host->transfer_one = mchp_corespi_transfer_one;
 	host->prepare_message = mchp_corespi_prepare_message;
 	host->set_cs = mchp_corespi_set_cs;

drivers/spi/spidev.c

@@ -734,6 +734,7 @@ static const struct of_device_id spidev_dt_ids[] = {
 	{ .compatible = "lwn,bk4", .data = &spidev_of_check },
 	{ .compatible = "menlo,m53cpld", .data = &spidev_of_check },
 	{ .compatible = "micron,spi-authenta", .data = &spidev_of_check },
+	{ .compatible = "rohm,bh2228fv", .data = &spidev_of_check },
 	{ .compatible = "rohm,dh2228fv", .data = &spidev_of_check },
 	{ .compatible = "semtech,sx1301", .data = &spidev_of_check },
 	{ .compatible = "silabs,em3581", .data = &spidev_of_check },