[PATCH v2 1/6] spi: Add SPIBSC driver

[Chris Brandt <chris.brandt@renesas.com>]

Add a driver for the SPIBSC controller in Renesas SoC devices.

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
---
v2:
 * Kconfig should only depended on ARCH_RENESAS, no individual SoCs
 * Added COMPILE_TEST to Kconfig
 * Made entire header C++ style comments
 * Removed pm_runtime code
 * Removed function spibsc_print_data() and just use print_hex_dump_debug()
 * Added lines spaces in between functions
 * Reduced TEND timeout from 25ms to 32us
 * Added fall through comment to case statement
 * Moved message checking from transfer_one_message to prepare_message
 * Change failures of message checking prints from dev_dbg to dev_err
 * Change failures of message checking to return -EINVAL instead of -EIO
 * Check bits_per_word using .bits_per_word_mask instead of in.setup()
 * Check for a subnode with "jedec,spi-nor" to determine the HW mode
 * removed "probed" dev_info print at the end
 * Removed compatible  "renesas,spibsc"
---
 drivers/spi/Kconfig      |   8 +
 drivers/spi/Makefile     |   1 +
 drivers/spi/spi-spibsc.c | 612 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 621 insertions(+)
 create mode 100644 drivers/spi/spi-spibsc.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 870f7797b56b..c80b46cd8d35 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -575,6 +575,14 @@ config SPI_RSPI
 	help
 	  SPI driver for Renesas RSPI and QSPI blocks.
 
+config SPI_SPIBSC
+	tristate "Renesas SPI Multi I/O Bus Controller"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	help
+	  Also referred to as the SPI Bus Space Controller (SPIBSC).
+	  This controller was designed specifically for accessing serial flash
+	  devices.
+
 config SPI_QCOM_QSPI
 	tristate "QTI QSPI controller"
 	depends on ARCH_QCOM
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index bb49c9e6d0a0..9525256c4d51 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -99,6 +99,7 @@ obj-$(CONFIG_SPI_SH_SCI)		+= spi-sh-sci.o
 obj-$(CONFIG_SPI_SIFIVE)		+= spi-sifive.o
 obj-$(CONFIG_SPI_SIRF)		+= spi-sirf.o
 obj-$(CONFIG_SPI_SLAVE_MT27XX)          += spi-slave-mt27xx.o
+obj-$(CONFIG_SPI_SPIBSC)		+= spi-spibsc.o
 obj-$(CONFIG_SPI_SPRD)			+= spi-sprd.o
 obj-$(CONFIG_SPI_SPRD_ADI)		+= spi-sprd-adi.o
 obj-$(CONFIG_SPI_STM32) 		+= spi-stm32.o
diff --git a/drivers/spi/spi-spibsc.c b/drivers/spi/spi-spibsc.c
new file mode 100644
index 000000000000..2c5bb249cdc5
--- /dev/null
+++ b/drivers/spi/spi-spibsc.c
@@ -0,0 +1,612 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// SPI Bus Space Controller (SPIBSC) bus driver
+// Otherwise known as a SPI Multi I/O Bus Controller
+//
+// Copyright (C) 2019 Renesas Electronics
+// Copyright (C) 2019 Chris Brandt
+//
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/spi/spi.h>
+
+/* SPIBSC registers */
+#define	CMNCR	0x00
+#define	SSLDR	0x04
+#define SPBCR	0x08
+#define DRCR	0x0c
+#define DRCMR	0x10
+#define DREAR	0x14
+#define DROPR	0x18
+#define DRENR	0x1c
+#define	SMCR	0x20
+#define	SMCMR	0x24
+#define	SMADR	0x28
+#define	SMOPR	0x2c
+#define	SMENR	0x30
+#define SMRDR0	0x38
+#define SMRDR1	0x3c
+#define	SMWDR0	0x40
+#define SMWDR1	0x44
+#define	CMNSR	0x48
+#define SMDMCR	0x60
+#define SMDRENR	0x64
+
+/* CMNCR */
+#define	CMNCR_MD	BIT(31)
+#define	CMNCR_SFDE	BIT(24)
+#define	CMNCR_MOIIO3(x)	(((u32)(x) & 0x3) << 22)
+#define	CMNCR_MOIIO2(x)	(((u32)(x) & 0x3) << 20)
+#define	CMNCR_MOIIO1(x)	(((u32)(x) & 0x3) << 18)
+#define	CMNCR_MOIIO0(x)	(((u32)(x) & 0x3) << 16)
+#define	CMNCR_IO3FV(x)	(((u32)(x) & 0x3) << 14)
+#define	CMNCR_IO2FV(x)	(((u32)(x) & 0x3) << 12)
+#define	CMNCR_IO0FV(x)	(((u32)(x) & 0x3) << 8)
+#define	CMNCR_CPHAT	BIT(6)
+#define	CMNCR_CPHAR	BIT(5)
+#define	CMNCR_SSLP	BIT(4)
+#define	CMNCR_CPOL	BIT(3)
+#define	CMNCR_BSZ(n)	(((u32)(n) & 0x3) << 0)
+#define	OUT_0		(0u)
+#define	OUT_1		(1u)
+#define	OUT_REV		(2u)
+#define	OUT_HIZ		(3u)
+#define	BSZ_SINGLE	(0)
+#define	BSZ_DUAL	(1)
+#define CMNCR_INIT	(CMNCR_MD | \
+			CMNCR_SFDE | \
+			CMNCR_MOIIO3(OUT_HIZ) | \
+			CMNCR_MOIIO2(OUT_HIZ) | \
+			CMNCR_MOIIO1(OUT_HIZ) | \
+			CMNCR_MOIIO0(OUT_HIZ) | \
+			CMNCR_IO3FV(OUT_HIZ) | \
+			CMNCR_IO2FV(OUT_HIZ) | \
+			CMNCR_IO0FV(OUT_HIZ) | \
+			CMNCR_CPHAR | \
+			CMNCR_BSZ(BSZ_SINGLE))
+
+/* SSLDR */
+#define	SSLDR_SPNDL(x)	(((u32)(x) & 0x7) << 16)
+#define	SSLDR_SLNDL(x)	(((u32)(x) & 0x7) << 8)
+#define	SSLDR_SCKDL(x)	(((u32)(x) & 0x7) << 0)
+#define	SSLDR_INIT	(SSLDR_SPNDL(3) | SSLDR_SLNDL(3) | SSLDR_SCKDL(3))
+
+/* SPBCR */
+#define	SPBCR_SPBR(x)	(((u32)(x) & 0xff) << 8)
+#define	SPBCR_BRDV(x)	(((u32)(x) & 0x3) << 0)
+
+/* DRCR (read mode) */
+#define	DRCR_SSLN	BIT(24)
+#define	DRCR_RBURST(x)	(((u32)(x) & 0xf) << 16)
+#define	DRCR_RCF	BIT(9)
+#define	DRCR_RBE	BIT(8)
+#define	DRCR_SSLE	BIT(0)
+
+/* DROPR (read mode) */
+#define	DROPR_OPD3(o)	(((u32)(o) & 0xff) << 24)
+#define	DROPR_OPD2(o)	(((u32)(o) & 0xff) << 16)
+#define	DROPR_OPD1(o)	(((u32)(o) & 0xff) << 8)
+#define	DROPR_OPD0(o)	(((u32)(o) & 0xff) << 0)
+
+/* DRENR (read mode) */
+#define	DRENR_CDE	BIT(14)
+#define	DRENR_OCDE	BIT(12)
+#define	DRENR_OPDE(o)	(((u32)(o) & 0xf) << 4)
+
+/* SMCR (spi mode) */
+#define	SMCR_SSLKP	BIT(8)
+#define	SMCR_SPIRE	BIT(2)
+#define	SMCR_SPIWE	BIT(1)
+#define	SMCR_SPIE	BIT(0)
+
+/* SMCMR (spi mode) */
+#define	SMCMR_CMD(c)	(((u32)(c) & 0xff) << 16)
+#define	SMCMR_OCMD(o)	(((u32)(o) & 0xff) << 0)
+
+/* SMENR (spi mode) */
+#define	SMENR_SPIDE(b)	(((u32)(b) & 0xf) << 0)
+#define	SPIDE_8BITS	(0x8)
+#define	SPIDE_16BITS	(0xc)
+#define	SPIDE_32BITS	(0xf)
+
+/* CMNSR (spi mode) */
+#define	CMNSR_SSLF	BIT(1)
+#define	CMNSR_TEND	BIT(0)
+
+#define MAX_CMD_LEN 6
+
+/* HW Option Flags */
+#define HAS_SPBCR BIT(0)
+
+struct spibsc_priv {
+	void __iomem *base;	/* register base */
+	void __iomem *mmio;	/* memory mapped io space of SPI Flash */
+	int mmio_size;
+	struct spi_controller *master;
+	struct device *dev;
+	struct clk *clk;
+	int last_xfer;
+	int tx_only;
+	u32 flags;
+};
+
+static void spibsc_write(struct spibsc_priv *sbsc, int reg, u32 val)
+{
+	iowrite32(val, sbsc->base + reg);
+}
+
+static void spibsc_write8(struct spibsc_priv *sbsc, int reg, u8 val)
+{
+	iowrite8(val, sbsc->base + reg);
+}
+
+static void spibsc_write16(struct spibsc_priv *sbsc, int reg, u16 val)
+{
+	iowrite16(val, sbsc->base + reg);
+}
+
+static u32 spibsc_read(struct spibsc_priv *sbsc, int reg)
+{
+	return ioread32(sbsc->base + reg);
+}
+
+static int spibsc_wait_trans_completion(struct spibsc_priv *sbsc)
+{
+	int t = 320; /* 32us = 4 bytes at 1MHz */
+
+	while (t--) {
+		if (spibsc_read(sbsc, CMNSR) & CMNSR_TEND)
+			return 0;
+		ndelay(100);
+	}
+
+	dev_err(sbsc->dev, "Timeout waiting for TEND\n");
+	return -ETIMEDOUT;
+}
+
+/*
+ * This function sends data using 'SPI operation mode'. It is intended to be
+ * used only with SPI Flash commands that do not require any reading back from
+ * the SPI flash.
+ */
+static int spibsc_send_data(struct spibsc_priv *sbsc, const u8 *data, int len)
+{
+	u32 smcr, smenr, smwdr0;
+	int ret, unit, sslkp;
+
+	/* print data (for debugging) */
+#if defined(DEBUG_PRINT_DATA)
+	print_hex_dump_debug("TX data: ", DUMP_PREFIX_NONE, 16, 1, data, len,
+			     false);
+#endif
+
+	while (len > 0) {
+		if (len >= 4) {
+			unit = 4;
+			smenr = SMENR_SPIDE(SPIDE_32BITS);
+		} else {
+			unit = len;
+			if (unit == 3)
+				unit = 2;
+
+			if (unit >= 2)
+				smenr = SMENR_SPIDE(SPIDE_16BITS);
+			else
+				smenr = SMENR_SPIDE(SPIDE_8BITS);
+		}
+
+		/* set 4bytes data, bit stream */
+		smwdr0 = *data++;
+		if (unit >= 2)
+			smwdr0 |= (u32)(*data++ << 8);
+		if (unit >= 3)
+			smwdr0 |= (u32)(*data++ << 16);
+		if (unit >= 4)
+			smwdr0 |= (u32)(*data++ << 24);
+
+		/* mask unwrite area */
+		if (unit == 3)
+			smwdr0 |= 0xFF000000;
+		else if (unit == 2)
+			smwdr0 |= 0xFFFF0000;
+		else if (unit == 1)
+			smwdr0 |= 0xFFFFFF00;
+
+		/* write send data. */
+		if (unit == 2)
+			spibsc_write16(sbsc, SMWDR0, (u16)smwdr0);
+		else if (unit == 1)
+			spibsc_write8(sbsc, SMWDR0, (u8)smwdr0);
+		else
+			spibsc_write(sbsc, SMWDR0, smwdr0);
+
+		len -= unit;
+		if ((len <= 0) && sbsc->last_xfer)
+			sslkp = 0;
+		else
+			sslkp = 1;
+
+		/* set params */
+		spibsc_write(sbsc, SMCMR, 0);
+		spibsc_write(sbsc, SMADR, 0);
+		spibsc_write(sbsc, SMOPR, 0);
+		spibsc_write(sbsc, SMENR, smenr);
+
+		/* start spi transfer */
+		smcr = SMCR_SPIE|SMCR_SPIWE;
+		if (sslkp)
+			smcr |= SMCR_SSLKP;
+		spibsc_write(sbsc, SMCR, smcr);
+
+		ret = spibsc_wait_trans_completion(sbsc);
+		if (ret)
+			return  ret;
+	}
+	return 0;
+}
+
+/*
+ * This function uses 'Data Read' mode to send the command (and address) then
+ * read data back out.
+ * The HW was designed such that you program the registers with the command,
+ * base address, additional command data, etc... But, that makes things too
+ * difficult because it means this driver has to pick out those parameters from
+ * the data stream that was passed.
+ * Instead, we will ignore how the HW was 'supposed' to be used and just
+ * blindly put the Tx data (commands) to send in the registers in the order
+ * in which we know they will be transmitted:
+ *
+ * [DRCMR.CMD]+[DRCMR.OCMD]+[DROPR.OPD3]+[DROPR.OPD2]+[DROPR.OPD1]+[DROPR.OPD0]
+ *
+ * We can send up to 6 bytes this way.
+ * We will tell the HW to skip sending the 'address' because we are secretly
+ * including it in the "command" and that way we can leave the address registers
+ * blank.
+ *
+ * Note that when reading data, the HW will read in 8-byte units which usually
+ * is not an issue for SPI Flash devices.
+ */
+static int spibsc_send_recv_data(struct spibsc_priv *sbsc, u8 *tx_data,
+				 int tx_len, u8 *rx_data, int rx_len)
+{
+	u32 drcmr, drenr, dropr;
+	u8 opde;
+
+	dev_dbg(sbsc->dev, "%s (tx=%d, rx=%d)\n", __func__, tx_len, rx_len);
+
+	if (tx_len > MAX_CMD_LEN) {
+		dev_err(sbsc->dev, "Command length too long (%d)", tx_len);
+		return -EIO;
+	}
+
+	if (rx_len > sbsc->mmio_size) {
+		dev_err(sbsc->dev, "Receive length too long (%d)", rx_len);
+		return -EIO;
+	}
+
+	/* Setup Data Read mode
+	 * Flush read cache and enable burst mode. Burst mode is required
+	 * in order to keep chip select low between read transfers, but it
+	 * also means data is read in 8-byte intervals.
+	 */
+	spibsc_write(sbsc, DRCR, DRCR_SSLN | DRCR_RCF | DRCR_RBE | DRCR_SSLE);
+	spibsc_read(sbsc, DRCR);
+
+	/* Enter Data Read mode */
+	spibsc_write(sbsc, CMNCR, 0x01FFF300);
+	drcmr = 0;
+	drenr = 0;
+	dropr = 0;
+	opde = 0;
+
+	if (tx_len >= 1) {
+		/* Use 'Command' register for the 1st byte */
+		drcmr |= SMCMR_CMD(tx_data[0]);
+		drenr |= DRENR_CDE;
+	}
+
+	if (tx_len >= 2) {
+		/* Use 'Optional Command' register for the 2nd byte */
+		drcmr |= SMCMR_OCMD(tx_data[1]);
+		drenr |= DRENR_OCDE;
+	}
+
+	/* Use 'Option Data' for 3rd-6th bytes */
+	switch (tx_len) {
+	case 6:
+		dropr |= DROPR_OPD0(tx_data[5]);
+		opde |= (1 << 0);
+		/* fall through */
+	case 5:
+		dropr |= DROPR_OPD1(tx_data[4]);
+		opde |= (1 << 1);
+		/* fall through */
+	case 4:
+		dropr |= DROPR_OPD2(tx_data[3]);
+		opde |= (1 << 2);
+		/* fall through */
+	case 3:
+		dropr |= DROPR_OPD3(tx_data[2]);
+		opde |= (1 << 3);
+		drenr |= DRENR_OPDE(opde);
+	}
+
+	spibsc_write(sbsc, DRCMR, drcmr);
+	spibsc_write(sbsc, DROPR, dropr);
+	spibsc_write(sbsc, DRENR, drenr);
+
+	/* This internal bus access is what will trigger the actual Tx/Rx
+	 * operation. Remember, we don't care about the address.
+	 */
+	memcpy(rx_data, sbsc->mmio, rx_len);
+
+	/* Deactivate chip select */
+	spibsc_write(sbsc, DRCR, DRCR_SSLN);
+
+	/* Print data (for debugging) */
+#if defined(DEBUG_PRINT_DATA)
+	print_hex_dump_debug("TX data: ", DUMP_PREFIX_NONE, 16, 1, tx_data,
+			     tx_len, false);
+	print_hex_dump_debug("RX data: ", DUMP_PREFIX_NONE, 16, 1, rx_data,
+			     rx_len, false);
+#endif
+	return 0;
+}
+
+static int spibsc_prepare_message(struct spi_controller *ctlr,
+				  struct spi_message *msg)
+{
+	struct spibsc_priv *sbsc = spi_controller_get_devdata(ctlr);
+	struct spi_transfer *t, *t_last;
+
+	sbsc->last_xfer = 0;
+	sbsc->tx_only = 1;
+
+	t_last = list_last_entry(&msg->transfers, struct spi_transfer,
+				 transfer_list);
+
+	t = list_first_entry(&msg->transfers, struct spi_transfer,
+			     transfer_list);
+
+	if (t->rx_buf) {
+		dev_err(sbsc->dev, "Cannot Rx without Tx first!\n");
+		return -EINVAL;
+	}
+
+	list_for_each_entry(t, &msg->transfers, transfer_list) {
+
+		if (t->rx_buf) {
+			sbsc->tx_only = 0;
+			if (t != t_last) {
+				dev_err(sbsc->dev, "RX transaction is not the last transaction!\n");
+				return -EINVAL;
+			}
+		}
+		if (t->cs_change) {
+			dev_err(sbsc->dev, "cs_change not supported");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int spibsc_transfer_one_message(struct spi_controller *master,
+				       struct spi_message *msg)
+{
+	struct spibsc_priv *sbsc = spi_controller_get_devdata(master);
+	struct spi_transfer *t, *t_last;
+	u8 tx_data[MAX_CMD_LEN];
+	u8 tx_len;
+	int ret;
+
+	t_last = list_last_entry(&msg->transfers, struct spi_transfer,
+				 transfer_list);
+
+	/* Tx Only (SPI Mode is used) */
+	if (sbsc->tx_only) {
+
+		dev_dbg(sbsc->dev, "%s: TX only\n", __func__);
+
+		/* Initialize for SPI Mode */
+		spibsc_write(sbsc, CMNCR, CMNCR_INIT);
+
+		/* Send messages */
+		list_for_each_entry(t, &msg->transfers, transfer_list) {
+
+			if (t == t_last)
+				sbsc->last_xfer = 1;
+
+			ret = spibsc_send_data(sbsc, t->tx_buf, t->len);
+			if (ret)
+				break;
+
+			msg->actual_length += t->len;
+		}
+
+		goto done;
+	}
+
+	/* Tx, then RX (Data Read Mode is used) */
+	dev_dbg(sbsc->dev, "%s: Tx then Rx\n", __func__);
+
+	/* Buffer up the transmit portion (cmd + addr) so we can send it all at
+	 * once
+	 */
+	tx_len = 0;
+	list_for_each_entry(t, &msg->transfers, transfer_list) {
+		if (t->tx_buf) {
+			if ((tx_len + t->len) > sizeof(tx_data)) {
+				dev_err(sbsc->dev, "Command too big (%d)\n",
+					tx_len + t->len);
+				return -EINVAL;
+			}
+			memcpy(tx_data + tx_len, t->tx_buf, t->len);
+			tx_len += t->len;
+		}
+
+		if (t->rx_buf)
+			ret = spibsc_send_recv_data(sbsc, tx_data, tx_len,
+						    t->rx_buf,  t->len);
+
+		msg->actual_length += t->len;
+	}
+
+done:
+	msg->status = ret;
+	spi_finalize_current_message(master);
+
+	return ret;
+}
+
+static int spibsc_setup(struct spi_device *spi)
+{
+	struct spibsc_priv *sbsc = spi_controller_get_devdata(spi->master);
+	u32 max_speed_hz;
+	unsigned long rate;
+	u8 spbr;
+	u8 div_ratio;
+
+	if (sbsc->flags & HAS_SPBCR) {
+		max_speed_hz = spi->max_speed_hz;
+		rate = clk_get_rate(sbsc->clk);
+
+		div_ratio = 2;
+		spbr = 1;
+		while ((rate / div_ratio) > max_speed_hz) {
+			spbr++;
+			div_ratio += 2;
+			if (spbr == 255)
+				break;
+		}
+		spibsc_write(sbsc, SPBCR, SPBCR_SPBR(spbr) | SPBCR_BRDV(0));
+		dev_dbg(sbsc->dev, "Clock set to %ld Hz\n", rate/div_ratio);
+	}
+
+	return 0;
+}
+
+static int spibsc_probe(struct platform_device *pdev)
+{
+	struct spi_controller *master;
+	struct device_node *flash;
+	struct spibsc_priv *sbsc;
+	struct resource *res;
+	int ret;
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*sbsc));
+	if (!master)
+		return -ENOMEM;
+
+	sbsc = spi_controller_get_devdata(master);
+	dev_set_drvdata(&pdev->dev, sbsc);
+	sbsc->master	= master;
+	sbsc->dev	= &pdev->dev;
+
+	sbsc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(sbsc->clk)) {
+		dev_err(&pdev->dev, "cannot get clock\n");
+		ret = PTR_ERR(sbsc->clk);
+		goto error;
+	}
+	clk_prepare_enable(sbsc->clk);
+
+	/* Check what mode the SPIBSC will be used in */
+	flash = of_get_next_child(pdev->dev.of_node, NULL);
+	if (!flash || !of_device_is_compatible(flash, "jedec,spi-nor")) {
+		/*
+		 * We will assume that the HW will not be used in SPI mode,
+		 * but instead only in memory mapped read mode. We will also
+		 * assume that the interface has already been configured
+		 * by the boot loader. At this point, no other setup is needed
+		 * and there is no reason to register a SPI controller.
+		 * We need to keep the clock enabled, otherwise it will get
+		 * turned off at the and of kernel boot if the kernel thinks no
+		 * one is using it.
+		 */
+		dev_info(&pdev->dev, "External Address Space Read Mode\n");
+		return 0;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sbsc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sbsc->base)) {
+		ret = PTR_ERR(sbsc->base);
+		goto error;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	sbsc->mmio_size = resource_size(res);
+	sbsc->mmio = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sbsc->mmio)) {
+		ret = PTR_ERR(sbsc->mmio);
+		goto error;
+	}
+
+	sbsc->flags = (u32) of_device_get_match_data(&pdev->dev);
+
+	master->bus_num = pdev->id;
+	master->num_chipselect	= 1;
+	master->mode_bits		= SPI_CPOL | SPI_CPHA;
+	master->bits_per_word_mask	= SPI_BPW_MASK(8);
+	master->setup			= spibsc_setup;
+	master->prepare_message		= spibsc_prepare_message;
+	master->transfer_one_message	= spibsc_transfer_one_message;
+	master->dev.of_node		= pdev->dev.of_node;
+
+	/* Initialize HW */
+	spibsc_write(sbsc, CMNCR, CMNCR_INIT);
+	spibsc_write(sbsc, DRCR, DRCR_RCF);
+	spibsc_write(sbsc, SSLDR, SSLDR_INIT);
+
+	ret = devm_spi_register_controller(&pdev->dev, master);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "spi_register_controller error.\n");
+		goto error;
+	}
+
+	return 0;
+
+error:
+	if (sbsc->clk && !IS_ERR(sbsc->clk))
+		clk_disable_unprepare(sbsc->clk);
+
+	spi_controller_put(master);
+
+	return ret;
+}
+
+static int spibsc_remove(struct platform_device *pdev)
+{
+	struct spibsc_priv *sbsc = dev_get_drvdata(&pdev->dev);
+
+	clk_disable_unprepare(sbsc->clk);
+
+	return 0;
+}
+
+static const struct of_device_id of_spibsc_match[] = {
+	{ .compatible = "renesas,r7s72100-spibsc", .data = (void *)HAS_SPBCR},
+	{ .compatible = "renesas,r7s9210-spibsc"},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, of_spibsc_match);
+
+static struct platform_driver spibsc_driver = {
+	.probe = spibsc_probe,
+	.remove = spibsc_remove,
+	.driver = {
+		.name = "spibsc",
+		.owner = THIS_MODULE,
+		.of_match_table = of_spibsc_match,
+	},
+};
+module_platform_driver(spibsc_driver);
+
+MODULE_DESCRIPTION("Renesas SPIBSC SPI Flash driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Chris Brandt");
-- 
2.23.0