diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 7222c76..e39fd38 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -24,6 +24,7 @@
 #include <linux/sh_dma.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/rspi.h>
+#include <linux/spinlock.h>
 
 #define RSPI_SPCR		0x00	/* Control Register */
 #define RSPI_SSLP		0x01	/* Slave Select Polarity Register */
@@ -79,8 +80,7 @@
 #define SPCR_BSWAP		0x01	/* Byte Swap of read-data for DMAC */
 
 /* SSLP - Slave Select Polarity Register */
-#define SSLP_SSL1P		0x02	/* SSL1 Signal Polarity Setting */
-#define SSLP_SSL0P		0x01	/* SSL0 Signal Polarity Setting */
+#define SSLP_SSLP(i)		BIT(i)	/* SSLi Signal Polarity Setting */
 
 /* SPPCR - Pin Control Register */
 #define SPPCR_MOIFE		0x20	/* MOSI Idle Value Fixing Enable */
@@ -159,8 +159,9 @@
 #define SPCMD_SPIMOD_DUAL	SPCMD_SPIMOD0
 #define SPCMD_SPIMOD_QUAD	SPCMD_SPIMOD1
 #define SPCMD_SPRW		0x0010	/* SPI Read/Write Access (Dual/Quad) */
-#define SPCMD_SSLA_MASK		0x0030	/* SSL Assert Signal Setting (RSPI) */
+#define SPCMD_SSLA(i)		((i) << 4)	/* SSL Assert Signal Setting */
 #define SPCMD_BRDV_MASK		0x000c	/* Bit Rate Division Setting */
+#define SPCMD_BRDV(brdv)	((brdv) << 2)
 #define SPCMD_CPOL		0x0002	/* Clock Polarity Setting */
 #define SPCMD_CPHA		0x0001	/* Clock Phase Setting */
 
@@ -179,9 +180,11 @@
 
 struct rspi_data {
 	void __iomem *addr;
-	u32 max_speed_hz;
+	u32 speed_hz;
 	struct spi_controller *ctlr;
+	struct platform_device *pdev;
 	wait_queue_head_t wait;
+	spinlock_t lock;		/* Protects RMW-access to RSPI_SSLP */
 	struct clk *clk;
 	u16 spcmd;
 	u8 spsr;
@@ -239,25 +242,41 @@
 	int (*set_config_register)(struct rspi_data *rspi, int access_size);
 	int (*transfer_one)(struct spi_controller *ctlr,
 			    struct spi_device *spi, struct spi_transfer *xfer);
-	u16 mode_bits;
+	u16 extra_mode_bits;
+	u16 min_div;
+	u16 max_div;
 	u16 flags;
 	u16 fifo_size;
+	u8 num_hw_ss;
 };
 
+static void rspi_set_rate(struct rspi_data *rspi)
+{
+	unsigned long clksrc;
+	int brdv = 0, spbr;
+
+	clksrc = clk_get_rate(rspi->clk);
+	spbr = DIV_ROUND_UP(clksrc, 2 * rspi->speed_hz) - 1;
+	while (spbr > 255 && brdv < 3) {
+		brdv++;
+		spbr = DIV_ROUND_UP(spbr + 1, 2) - 1;
+	}
+
+	rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR);
+	rspi->spcmd |= SPCMD_BRDV(brdv);
+	rspi->speed_hz = DIV_ROUND_UP(clksrc, (2U << brdv) * (spbr + 1));
+}
+
 /*
  * functions for RSPI on legacy SH
  */
 static int rspi_set_config_register(struct rspi_data *rspi, int access_size)
 {
-	int spbr;
-
 	/* Sets output mode, MOSI signal, and (optionally) loopback */
 	rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
 	/* Sets transfer bit rate */
-	spbr = DIV_ROUND_UP(clk_get_rate(rspi->clk),
-			    2 * rspi->max_speed_hz) - 1;
-	rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR);
+	rspi_set_rate(rspi);
 
 	/* Disable dummy transmission, set 16-bit word access, 1 frame */
 	rspi_write8(rspi, 0, RSPI_SPDCR);
@@ -287,25 +306,11 @@
  */
 static int rspi_rz_set_config_register(struct rspi_data *rspi, int access_size)
 {
-	int spbr;
-	int div = 0;
-	unsigned long clksrc;
-
 	/* Sets output mode, MOSI signal, and (optionally) loopback */
 	rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
-	clksrc = clk_get_rate(rspi->clk);
-	while (div < 3) {
-		if (rspi->max_speed_hz >= clksrc/4) /* 4=(CLK/2)/2 */
-			break;
-		div++;
-		clksrc /= 2;
-	}
-
 	/* Sets transfer bit rate */
-	spbr = DIV_ROUND_UP(clksrc, 2 * rspi->max_speed_hz) - 1;
-	rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR);
-	rspi->spcmd |= div << 2;
+	rspi_set_rate(rspi);
 
 	/* Disable dummy transmission, set byte access */
 	rspi_write8(rspi, SPDCR_SPLBYTE, RSPI_SPDCR);
@@ -332,14 +337,28 @@
  */
 static int qspi_set_config_register(struct rspi_data *rspi, int access_size)
 {
-	int spbr;
+	unsigned long clksrc;
+	int brdv = 0, spbr;
 
 	/* Sets output mode, MOSI signal, and (optionally) loopback */
 	rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
 	/* Sets transfer bit rate */
-	spbr = DIV_ROUND_UP(clk_get_rate(rspi->clk), 2 * rspi->max_speed_hz);
-	rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR);
+	clksrc = clk_get_rate(rspi->clk);
+	if (rspi->speed_hz >= clksrc) {
+		spbr = 0;
+		rspi->speed_hz = clksrc;
+	} else {
+		spbr = DIV_ROUND_UP(clksrc, 2 * rspi->speed_hz);
+		while (spbr > 255 && brdv < 3) {
+			brdv++;
+			spbr = DIV_ROUND_UP(spbr, 2);
+		}
+		spbr = clamp(spbr, 0, 255);
+		rspi->speed_hz = DIV_ROUND_UP(clksrc, (2U << brdv) * spbr);
+	}
+	rspi_write8(rspi, spbr, RSPI_SPBR);
+	rspi->spcmd |= SPCMD_BRDV(brdv);
 
 	/* Disable dummy transmission, set byte access */
 	rspi_write8(rspi, 0, RSPI_SPDCR);
@@ -426,8 +445,6 @@
 	return n;
 }
 
-#define set_config_register(spi, n) spi->ops->set_config_register(spi, n)
-
 static void rspi_enable_irq(const struct rspi_data *rspi, u8 enable)
 {
 	rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | enable, RSPI_SPCR);
@@ -620,9 +637,8 @@
 		dmaengine_terminate_all(rspi->ctlr->dma_rx);
 no_dma_rx:
 	if (ret == -EAGAIN) {
-		pr_warn_once("%s %s: DMA not available, falling back to PIO\n",
-			     dev_driver_string(&rspi->ctlr->dev),
-			     dev_name(&rspi->ctlr->dev));
+		dev_warn_once(&rspi->ctlr->dev,
+			      "DMA not available, falling back to PIO\n");
 	}
 	return ret;
 }
@@ -687,6 +703,8 @@
 {
 	int ret;
 
+	xfer->effective_speed_hz = rspi->speed_hz;
+
 	ret = rspi_dma_check_then_transfer(rspi, xfer);
 	if (ret != -EAGAIN)
 		return ret;
@@ -842,6 +860,7 @@
 {
 	struct rspi_data *rspi = spi_controller_get_devdata(ctlr);
 
+	xfer->effective_speed_hz = rspi->speed_hz;
 	if (spi->mode & SPI_LOOP) {
 		return qspi_transfer_out_in(rspi, xfer);
 	} else if (xfer->tx_nbits > SPI_NBITS_SINGLE) {
@@ -921,27 +940,71 @@
 	return 0;
 }
 
+static int rspi_setup(struct spi_device *spi)
+{
+	struct rspi_data *rspi = spi_controller_get_devdata(spi->controller);
+	u8 sslp;
+
+	if (spi->cs_gpiod)
+		return 0;
+
+	pm_runtime_get_sync(&rspi->pdev->dev);
+	spin_lock_irq(&rspi->lock);
+
+	sslp = rspi_read8(rspi, RSPI_SSLP);
+	if (spi->mode & SPI_CS_HIGH)
+		sslp |= SSLP_SSLP(spi->chip_select);
+	else
+		sslp &= ~SSLP_SSLP(spi->chip_select);
+	rspi_write8(rspi, sslp, RSPI_SSLP);
+
+	spin_unlock_irq(&rspi->lock);
+	pm_runtime_put(&rspi->pdev->dev);
+	return 0;
+}
+
 static int rspi_prepare_message(struct spi_controller *ctlr,
 				struct spi_message *msg)
 {
 	struct rspi_data *rspi = spi_controller_get_devdata(ctlr);
 	struct spi_device *spi = msg->spi;
+	const struct spi_transfer *xfer;
 	int ret;
 
-	rspi->max_speed_hz = spi->max_speed_hz;
+	/*
+	 * As the Bit Rate Register must not be changed while the device is
+	 * active, all transfers in a message must use the same bit rate.
+	 * In theory, the sequencer could be enabled, and each Command Register
+	 * could divide the base bit rate by a different value.
+	 * However, most RSPI variants do not have Transfer Data Length
+	 * Multiplier Setting Registers, so each sequence step would be limited
+	 * to a single word, making this feature unsuitable for large
+	 * transfers, which would gain most from it.
+	 */
+	rspi->speed_hz = spi->max_speed_hz;
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		if (xfer->speed_hz < rspi->speed_hz)
+			rspi->speed_hz = xfer->speed_hz;
+	}
 
 	rspi->spcmd = SPCMD_SSLKP;
 	if (spi->mode & SPI_CPOL)
 		rspi->spcmd |= SPCMD_CPOL;
 	if (spi->mode & SPI_CPHA)
 		rspi->spcmd |= SPCMD_CPHA;
+	if (spi->mode & SPI_LSB_FIRST)
+		rspi->spcmd |= SPCMD_LSBF;
+
+	/* Configure slave signal to assert */
+	rspi->spcmd |= SPCMD_SSLA(spi->cs_gpiod ? rspi->ctlr->unused_native_cs
+						: spi->chip_select);
 
 	/* CMOS output mode and MOSI signal from previous transfer */
 	rspi->sppcr = 0;
 	if (spi->mode & SPI_LOOP)
 		rspi->sppcr |= SPPCR_SPLP;
 
-	set_config_register(rspi, 8);
+	rspi->ops->set_config_register(rspi, 8);
 
 	if (msg->spi->mode &
 	    (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)) {
@@ -1120,27 +1183,33 @@
 static const struct spi_ops rspi_ops = {
 	.set_config_register =	rspi_set_config_register,
 	.transfer_one =		rspi_transfer_one,
-	.mode_bits =		SPI_CPHA | SPI_CPOL | SPI_LOOP,
+	.min_div =		2,
+	.max_div =		4096,
 	.flags =		SPI_CONTROLLER_MUST_TX,
 	.fifo_size =		8,
+	.num_hw_ss =		2,
 };
 
 static const struct spi_ops rspi_rz_ops = {
 	.set_config_register =	rspi_rz_set_config_register,
 	.transfer_one =		rspi_rz_transfer_one,
-	.mode_bits =		SPI_CPHA | SPI_CPOL | SPI_LOOP,
+	.min_div =		2,
+	.max_div =		4096,
 	.flags =		SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX,
 	.fifo_size =		8,	/* 8 for TX, 32 for RX */
+	.num_hw_ss =		1,
 };
 
 static const struct spi_ops qspi_ops = {
 	.set_config_register =	qspi_set_config_register,
 	.transfer_one =		qspi_transfer_one,
-	.mode_bits =		SPI_CPHA | SPI_CPOL | SPI_LOOP |
-				SPI_TX_DUAL | SPI_TX_QUAD |
+	.extra_mode_bits =	SPI_TX_DUAL | SPI_TX_QUAD |
 				SPI_RX_DUAL | SPI_RX_QUAD,
+	.min_div =		1,
+	.max_div =		4080,
 	.flags =		SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX,
 	.fifo_size =		32,
+	.num_hw_ss =		1,
 };
 
 #ifdef CONFIG_OF
@@ -1199,6 +1268,7 @@
 	int ret;
 	const struct rspi_plat_data *rspi_pd;
 	const struct spi_ops *ops;
+	unsigned long clksrc;
 
 	ctlr = spi_alloc_master(&pdev->dev, sizeof(struct rspi_data));
 	if (ctlr == NULL)
@@ -1218,13 +1288,6 @@
 			ctlr->num_chipselect = 2; /* default */
 	}
 
-	/* ops parameter check */
-	if (!ops->set_config_register) {
-		dev_err(&pdev->dev, "there is no set_config_register\n");
-		ret = -ENODEV;
-		goto error1;
-	}
-
 	rspi = spi_controller_get_devdata(ctlr);
 	platform_set_drvdata(pdev, rspi);
 	rspi->ops = ops;
@@ -1244,18 +1307,27 @@
 		goto error1;
 	}
 
+	rspi->pdev = pdev;
 	pm_runtime_enable(&pdev->dev);
 
 	init_waitqueue_head(&rspi->wait);
+	spin_lock_init(&rspi->lock);
 
 	ctlr->bus_num = pdev->id;
+	ctlr->setup = rspi_setup;
 	ctlr->auto_runtime_pm = true;
 	ctlr->transfer_one = ops->transfer_one;
 	ctlr->prepare_message = rspi_prepare_message;
 	ctlr->unprepare_message = rspi_unprepare_message;
-	ctlr->mode_bits = ops->mode_bits;
+	ctlr->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST |
+			  SPI_LOOP | ops->extra_mode_bits;
+	clksrc = clk_get_rate(rspi->clk);
+	ctlr->min_speed_hz = DIV_ROUND_UP(clksrc, ops->max_div);
+	ctlr->max_speed_hz = DIV_ROUND_UP(clksrc, ops->min_div);
 	ctlr->flags = ops->flags;
 	ctlr->dev.of_node = pdev->dev.of_node;
+	ctlr->use_gpio_descriptors = true;
+	ctlr->max_native_cs = rspi->ops->num_hw_ss;
 
 	ret = platform_get_irq_byname_optional(pdev, "rx");
 	if (ret < 0) {
@@ -1314,8 +1386,6 @@
 
 static const struct platform_device_id spi_driver_ids[] = {
 	{ "rspi",	(kernel_ulong_t)&rspi_ops },
-	{ "rspi-rz",	(kernel_ulong_t)&rspi_rz_ops },
-	{ "qspi",	(kernel_ulong_t)&qspi_ops },
 	{},
 };