drivers/spi/spi-orion.c - kernel/msm-4.9 - Gitiles

 /*
  * Marvell Orion SPI controller driver
  *
  * Author: Shadi Ammouri <shadi@marvell.com>
  * Copyright (C) 2007-2008 Marvell Ltd.
  *
  * 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/interrupt.h>
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/spi/spi.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/clk.h>
 #include <linux/sizes.h>
 #include <asm/unaligned.h>

 #define DRIVER_NAME			"orion_spi"

 #define ORION_NUM_CHIPSELECTS		1 /* only one slave is supported*/
 #define ORION_SPI_WAIT_RDY_MAX_LOOP	2000 /* in usec */

 #define ORION_SPI_IF_CTRL_REG		0x00
 #define ORION_SPI_IF_CONFIG_REG		0x04
 #define ORION_SPI_DATA_OUT_REG		0x08
 #define ORION_SPI_DATA_IN_REG		0x0c
 #define ORION_SPI_INT_CAUSE_REG		0x10

 #define ORION_SPI_MODE_CPOL		(1 << 11)
 #define ORION_SPI_MODE_CPHA		(1 << 12)
 #define ORION_SPI_IF_8_16_BIT_MODE	(1 << 5)
 #define ORION_SPI_CLK_PRESCALE_MASK	0x1F
 #define ORION_SPI_MODE_MASK		(ORION_SPI_MODE_CPOL | \
 					 ORION_SPI_MODE_CPHA)

 struct orion_spi {
 	struct spi_master	*master;
 	void __iomem		*base;
 	struct clk              *clk;
 };

 static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
 {
 	return orion_spi->base + reg;
 }

 static inline void
 orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
 {
 	void __iomem *reg_addr = spi_reg(orion_spi, reg);
 	u32 val;

 	val = readl(reg_addr);
 	val |= mask;
 	writel(val, reg_addr);
 }

 static inline void
 orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
 {
 	void __iomem *reg_addr = spi_reg(orion_spi, reg);
 	u32 val;

 	val = readl(reg_addr);
 	val &= ~mask;
 	writel(val, reg_addr);
 }

 static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
 {
 	u32 tclk_hz;
 	u32 rate;
 	u32 prescale;
 	u32 reg;
 	struct orion_spi *orion_spi;

 	orion_spi = spi_master_get_devdata(spi->master);

 	tclk_hz = clk_get_rate(orion_spi->clk);

 	/*
 	 * the supported rates are: 4,6,8...30
 	 * round up as we look for equal or less speed
 	 */
 	rate = DIV_ROUND_UP(tclk_hz, speed);
 	rate = roundup(rate, 2);

 	/* check if requested speed is too small */
 	if (rate > 30)
 		return -EINVAL;

 	if (rate < 4)
 		rate = 4;

 	/* Convert the rate to SPI clock divisor value.	*/
 	prescale = 0x10 + rate/2;

 	reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
 	reg = ((reg & ~ORION_SPI_CLK_PRESCALE_MASK) | prescale);
 	writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));

 	return 0;
 }

 static void
 orion_spi_mode_set(struct spi_device *spi)
 {
 	u32 reg;
 	struct orion_spi *orion_spi;

 	orion_spi = spi_master_get_devdata(spi->master);

 	reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
 	reg &= ~ORION_SPI_MODE_MASK;
 	if (spi->mode & SPI_CPOL)
 		reg |= ORION_SPI_MODE_CPOL;
 	if (spi->mode & SPI_CPHA)
 		reg |= ORION_SPI_MODE_CPHA;
 	writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
 }

 /*
  * called only when no transfer is active on the bus
  */
 static int
 orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 {
 	struct orion_spi *orion_spi;
 	unsigned int speed = spi->max_speed_hz;
 	unsigned int bits_per_word = spi->bits_per_word;
 	int	rc;

 	orion_spi = spi_master_get_devdata(spi->master);

 	if ((t != NULL) && t->speed_hz)
 		speed = t->speed_hz;

 	if ((t != NULL) && t->bits_per_word)
 		bits_per_word = t->bits_per_word;

 	orion_spi_mode_set(spi);

 	rc = orion_spi_baudrate_set(spi, speed);
 	if (rc)
 		return rc;

 	if (bits_per_word == 16)
 		orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
 				  ORION_SPI_IF_8_16_BIT_MODE);
 	else
 		orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
 				  ORION_SPI_IF_8_16_BIT_MODE);

 	return 0;
 }

 static void orion_spi_set_cs(struct orion_spi *orion_spi, int enable)
 {
 	if (enable)
 		orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
 	else
 		orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
 }

 static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
 {
 	int i;

 	for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
 		if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
 			return 1;
 		else
 			udelay(1);
 	}

 	return -1;
 }

 static inline int
 orion_spi_write_read_8bit(struct spi_device *spi,
 			  const u8 **tx_buf, u8 **rx_buf)
 {
 	void __iomem *tx_reg, *rx_reg, *int_reg;
 	struct orion_spi *orion_spi;

 	orion_spi = spi_master_get_devdata(spi->master);
 	tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
 	rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
 	int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);

 	/* clear the interrupt cause register */
 	writel(0x0, int_reg);

 	if (tx_buf && *tx_buf)
 		writel(*(*tx_buf)++, tx_reg);
 	else
 		writel(0, tx_reg);

 	if (orion_spi_wait_till_ready(orion_spi) < 0) {
 		dev_err(&spi->dev, "TXS timed out\n");
 		return -1;
 	}

 	if (rx_buf && *rx_buf)
 		*(*rx_buf)++ = readl(rx_reg);

 	return 1;
 }

 static inline int
 orion_spi_write_read_16bit(struct spi_device *spi,
 			   const u16 **tx_buf, u16 **rx_buf)
 {
 	void __iomem *tx_reg, *rx_reg, *int_reg;
 	struct orion_spi *orion_spi;

 	orion_spi = spi_master_get_devdata(spi->master);
 	tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
 	rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
 	int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);

 	/* clear the interrupt cause register */
 	writel(0x0, int_reg);

 	if (tx_buf && *tx_buf)
 		writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
 	else
 		writel(0, tx_reg);

 	if (orion_spi_wait_till_ready(orion_spi) < 0) {
 		dev_err(&spi->dev, "TXS timed out\n");
 		return -1;
 	}

 	if (rx_buf && *rx_buf)
 		put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);

 	return 1;
 }

 static unsigned int
 orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
 {
 	unsigned int count;
 	int word_len;

 	word_len = spi->bits_per_word;
 	count = xfer->len;

 	if (word_len == 8) {
 		const u8 *tx = xfer->tx_buf;
 		u8 *rx = xfer->rx_buf;

 		do {
 			if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
 				goto out;
 			count--;
 		} while (count);
 	} else if (word_len == 16) {
 		const u16 *tx = xfer->tx_buf;
 		u16 *rx = xfer->rx_buf;

 		do {
 			if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
 				goto out;
 			count -= 2;
 		} while (count);
 	}

 out:
 	return xfer->len - count;
 }


 static int orion_spi_transfer_one_message(struct spi_master *master,
 					   struct spi_message *m)
 {
 	struct orion_spi *orion_spi = spi_master_get_devdata(master);
 	struct spi_device *spi = m->spi;
 	struct spi_transfer *t = NULL;
 	int par_override = 0;
 	int status = 0;
 	int cs_active = 0;

 	/* Load defaults */
 	status = orion_spi_setup_transfer(spi, NULL);

 	if (status < 0)
 		goto msg_done;

 	list_for_each_entry(t, &m->transfers, transfer_list) {
 		if (par_override || t->speed_hz || t->bits_per_word) {
 			par_override = 1;
 			status = orion_spi_setup_transfer(spi, t);
 			if (status < 0)
 				break;
 			if (!t->speed_hz && !t->bits_per_word)
 				par_override = 0;
 		}

 		if (!cs_active) {
 			orion_spi_set_cs(orion_spi, 1);
 			cs_active = 1;
 		}

 		if (t->len)
 			m->actual_length += orion_spi_write_read(spi, t);

 		if (t->delay_usecs)
 			udelay(t->delay_usecs);

 		if (t->cs_change) {
 			orion_spi_set_cs(orion_spi, 0);
 			cs_active = 0;
 		}
 	}

 msg_done:
 	if (cs_active)
 		orion_spi_set_cs(orion_spi, 0);

 	m->status = status;
 	spi_finalize_current_message(master);

 	return 0;
 }

 static int orion_spi_reset(struct orion_spi *orion_spi)
 {
 	/* Verify that the CS is deasserted */
 	orion_spi_set_cs(orion_spi, 0);

 	return 0;
 }

 static int orion_spi_probe(struct platform_device *pdev)
 {
 	struct spi_master *master;
 	struct orion_spi *spi;
 	struct resource *r;
 	unsigned long tclk_hz;
 	int status = 0;

 	master = spi_alloc_master(&pdev->dev, sizeof(*spi));
 	if (master == NULL) {
 		dev_dbg(&pdev->dev, "master allocation failed\n");
 		return -ENOMEM;
 	}

 	if (pdev->id != -1)
 		master->bus_num = pdev->id;
 	if (pdev->dev.of_node) {
 		u32 cell_index;
 		if (!of_property_read_u32(pdev->dev.of_node, "cell-index",
 					  &cell_index))
 			master->bus_num = cell_index;
 	}

 	/* we support only mode 0, and no options */
 	master->mode_bits = SPI_CPHA | SPI_CPOL;

 	master->transfer_one_message = orion_spi_transfer_one_message;
 	master->num_chipselect = ORION_NUM_CHIPSELECTS;
 	master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);

 	platform_set_drvdata(pdev, master);

 	spi = spi_master_get_devdata(master);
 	spi->master = master;

 	spi->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(spi->clk)) {
 		status = PTR_ERR(spi->clk);
 		goto out;
 	}

 	clk_prepare(spi->clk);
 	clk_enable(spi->clk);
 	tclk_hz = clk_get_rate(spi->clk);
 	master->max_speed_hz = DIV_ROUND_UP(tclk_hz, 4);
 	master->min_speed_hz = DIV_ROUND_UP(tclk_hz, 30);

 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	spi->base = devm_ioremap_resource(&pdev->dev, r);
 	if (IS_ERR(spi->base)) {
 		status = PTR_ERR(spi->base);
 		goto out_rel_clk;
 	}

 	if (orion_spi_reset(spi) < 0)
 		goto out_rel_clk;

 	master->dev.of_node = pdev->dev.of_node;
 	status = devm_spi_register_master(&pdev->dev, master);
 	if (status < 0)
 		goto out_rel_clk;

 	return status;

 out_rel_clk:
 	clk_disable_unprepare(spi->clk);
 out:
 	spi_master_put(master);
 	return status;
 }


 static int orion_spi_remove(struct platform_device *pdev)
 {
 	struct spi_master *master;
 	struct orion_spi *spi;

 	master = platform_get_drvdata(pdev);
 	spi = spi_master_get_devdata(master);

 	clk_disable_unprepare(spi->clk);

 	return 0;
 }

 MODULE_ALIAS("platform:" DRIVER_NAME);

 static const struct of_device_id orion_spi_of_match_table[] = {
 	{ .compatible = "marvell,orion-spi", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, orion_spi_of_match_table);

 static struct platform_driver orion_spi_driver = {
 	.driver = {
 		.name	= DRIVER_NAME,
 		.owner	= THIS_MODULE,
 		.of_match_table = of_match_ptr(orion_spi_of_match_table),
 	},
 	.probe		= orion_spi_probe,
 	.remove		= orion_spi_remove,
 };

 module_platform_driver(orion_spi_driver);

 MODULE_DESCRIPTION("Orion SPI driver");
 MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
 MODULE_LICENSE("GPL");
	/*
	* Marvell Orion SPI controller driver
	*
	* Author: Shadi Ammouri <shadi@marvell.com>
	* Copyright (C) 2007-2008 Marvell Ltd.
	*
	* 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/interrupt.h>
	#include <linux/delay.h>
	#include <linux/platform_device.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/spi/spi.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/clk.h>
	#include <linux/sizes.h>
	#include <asm/unaligned.h>

	#define DRIVER_NAME "orion_spi"

	#define ORION_NUM_CHIPSELECTS 1 /* only one slave is supported*/
	#define ORION_SPI_WAIT_RDY_MAX_LOOP 2000 /* in usec */

	#define ORION_SPI_IF_CTRL_REG 0x00
	#define ORION_SPI_IF_CONFIG_REG 0x04
	#define ORION_SPI_DATA_OUT_REG 0x08
	#define ORION_SPI_DATA_IN_REG 0x0c
	#define ORION_SPI_INT_CAUSE_REG 0x10

	#define ORION_SPI_MODE_CPOL (1 << 11)
	#define ORION_SPI_MODE_CPHA (1 << 12)
	#define ORION_SPI_IF_8_16_BIT_MODE (1 << 5)
	#define ORION_SPI_CLK_PRESCALE_MASK 0x1F
	#define ORION_SPI_MODE_MASK (ORION_SPI_MODE_CPOL \| \
	ORION_SPI_MODE_CPHA)

	struct orion_spi {
	struct spi_master *master;
	void __iomem *base;
	struct clk *clk;
	};

	static inline void __iomem spi_reg(struct orion_spi orion_spi, u32 reg)
	{
	return orion_spi->base + reg;
	}

	static inline void
	orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
	{
	void __iomem *reg_addr = spi_reg(orion_spi, reg);
	u32 val;

	val = readl(reg_addr);
	val \|= mask;
	writel(val, reg_addr);
	}

	static inline void
	orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
	{
	void __iomem *reg_addr = spi_reg(orion_spi, reg);
	u32 val;

	val = readl(reg_addr);
	val &= ~mask;
	writel(val, reg_addr);
	}

	static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
	{
	u32 tclk_hz;
	u32 rate;
	u32 prescale;
	u32 reg;
	struct orion_spi *orion_spi;

	orion_spi = spi_master_get_devdata(spi->master);

	tclk_hz = clk_get_rate(orion_spi->clk);

	/*
	* the supported rates are: 4,6,8...30
	* round up as we look for equal or less speed
	*/
	rate = DIV_ROUND_UP(tclk_hz, speed);
	rate = roundup(rate, 2);

	/* check if requested speed is too small */
	if (rate > 30)
	return -EINVAL;

	if (rate < 4)
	rate = 4;

	/* Convert the rate to SPI clock divisor value. */
	prescale = 0x10 + rate/2;

	reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
	reg = ((reg & ~ORION_SPI_CLK_PRESCALE_MASK) \| prescale);
	writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));

	return 0;
	}

	static void
	orion_spi_mode_set(struct spi_device *spi)
	{
	u32 reg;
	struct orion_spi *orion_spi;

	orion_spi = spi_master_get_devdata(spi->master);

	reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
	reg &= ~ORION_SPI_MODE_MASK;
	if (spi->mode & SPI_CPOL)
	reg \|= ORION_SPI_MODE_CPOL;
	if (spi->mode & SPI_CPHA)
	reg \|= ORION_SPI_MODE_CPHA;
	writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
	}

	/*
	* called only when no transfer is active on the bus
	*/
	static int
	orion_spi_setup_transfer(struct spi_device spi, struct spi_transfer t)
	{
	struct orion_spi *orion_spi;
	unsigned int speed = spi->max_speed_hz;
	unsigned int bits_per_word = spi->bits_per_word;
	int rc;

	orion_spi = spi_master_get_devdata(spi->master);

	if ((t != NULL) && t->speed_hz)
	speed = t->speed_hz;

	if ((t != NULL) && t->bits_per_word)
	bits_per_word = t->bits_per_word;

	orion_spi_mode_set(spi);

	rc = orion_spi_baudrate_set(spi, speed);
	if (rc)
	return rc;

	if (bits_per_word == 16)
	orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
	ORION_SPI_IF_8_16_BIT_MODE);
	else
	orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
	ORION_SPI_IF_8_16_BIT_MODE);

	return 0;
	}

	static void orion_spi_set_cs(struct orion_spi *orion_spi, int enable)
	{
	if (enable)
	orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
	else
	orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
	}

	static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
	{
	int i;

	for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
	if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
	return 1;
	else
	udelay(1);
	}

	return -1;
	}

	static inline int
	orion_spi_write_read_8bit(struct spi_device *spi,
	const u8 tx_buf, u8 rx_buf)
	{
	void __iomem tx_reg, rx_reg, *int_reg;
	struct orion_spi *orion_spi;

	orion_spi = spi_master_get_devdata(spi->master);
	tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
	rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
	int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);

	/* clear the interrupt cause register */
	writel(0x0, int_reg);

	if (tx_buf && *tx_buf)
	writel((tx_buf)++, tx_reg);
	else
	writel(0, tx_reg);

	if (orion_spi_wait_till_ready(orion_spi) < 0) {
	dev_err(&spi->dev, "TXS timed out\n");
	return -1;
	}

	if (rx_buf && *rx_buf)
	(rx_buf)++ = readl(rx_reg);

	return 1;
	}

	static inline int
	orion_spi_write_read_16bit(struct spi_device *spi,
	const u16 tx_buf, u16 rx_buf)
	{
	void __iomem tx_reg, rx_reg, *int_reg;
	struct orion_spi *orion_spi;

	orion_spi = spi_master_get_devdata(spi->master);
	tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
	rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
	int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);

	/* clear the interrupt cause register */
	writel(0x0, int_reg);

	if (tx_buf && *tx_buf)
	writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
	else
	writel(0, tx_reg);

	if (orion_spi_wait_till_ready(orion_spi) < 0) {
	dev_err(&spi->dev, "TXS timed out\n");
	return -1;
	}

	if (rx_buf && *rx_buf)
	put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);

	return 1;
	}

	static unsigned int
	orion_spi_write_read(struct spi_device spi, struct spi_transfer xfer)
	{
	unsigned int count;
	int word_len;

	word_len = spi->bits_per_word;
	count = xfer->len;

	if (word_len == 8) {
	const u8 *tx = xfer->tx_buf;
	u8 *rx = xfer->rx_buf;

	do {
	if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
	goto out;
	count--;
	} while (count);
	} else if (word_len == 16) {
	const u16 *tx = xfer->tx_buf;
	u16 *rx = xfer->rx_buf;

	do {
	if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
	goto out;
	count -= 2;
	} while (count);
	}

	out:
	return xfer->len - count;
	}


	static int orion_spi_transfer_one_message(struct spi_master *master,
	struct spi_message *m)
	{
	struct orion_spi *orion_spi = spi_master_get_devdata(master);
	struct spi_device *spi = m->spi;
	struct spi_transfer *t = NULL;
	int par_override = 0;
	int status = 0;
	int cs_active = 0;

	/* Load defaults */
	status = orion_spi_setup_transfer(spi, NULL);

	if (status < 0)
	goto msg_done;

	list_for_each_entry(t, &m->transfers, transfer_list) {
	if (par_override \|\| t->speed_hz \|\| t->bits_per_word) {
	par_override = 1;
	status = orion_spi_setup_transfer(spi, t);
	if (status < 0)
	break;
	if (!t->speed_hz && !t->bits_per_word)
	par_override = 0;
	}

	if (!cs_active) {
	orion_spi_set_cs(orion_spi, 1);
	cs_active = 1;
	}

	if (t->len)
	m->actual_length += orion_spi_write_read(spi, t);

	if (t->delay_usecs)
	udelay(t->delay_usecs);

	if (t->cs_change) {
	orion_spi_set_cs(orion_spi, 0);
	cs_active = 0;
	}
	}

	msg_done:
	if (cs_active)
	orion_spi_set_cs(orion_spi, 0);

	m->status = status;
	spi_finalize_current_message(master);

	return 0;
	}

	static int orion_spi_reset(struct orion_spi *orion_spi)
	{
	/* Verify that the CS is deasserted */
	orion_spi_set_cs(orion_spi, 0);

	return 0;
	}

	static int orion_spi_probe(struct platform_device *pdev)
	{
	struct spi_master *master;
	struct orion_spi *spi;
	struct resource *r;
	unsigned long tclk_hz;
	int status = 0;

	master = spi_alloc_master(&pdev->dev, sizeof(*spi));
	if (master == NULL) {
	dev_dbg(&pdev->dev, "master allocation failed\n");
	return -ENOMEM;
	}

	if (pdev->id != -1)
	master->bus_num = pdev->id;
	if (pdev->dev.of_node) {
	u32 cell_index;
	if (!of_property_read_u32(pdev->dev.of_node, "cell-index",
	&cell_index))
	master->bus_num = cell_index;
	}

	/* we support only mode 0, and no options */
	master->mode_bits = SPI_CPHA \| SPI_CPOL;

	master->transfer_one_message = orion_spi_transfer_one_message;
	master->num_chipselect = ORION_NUM_CHIPSELECTS;
	master->bits_per_word_mask = SPI_BPW_MASK(8) \| SPI_BPW_MASK(16);

	platform_set_drvdata(pdev, master);

	spi = spi_master_get_devdata(master);
	spi->master = master;

	spi->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(spi->clk)) {
	status = PTR_ERR(spi->clk);
	goto out;
	}

	clk_prepare(spi->clk);
	clk_enable(spi->clk);
	tclk_hz = clk_get_rate(spi->clk);
	master->max_speed_hz = DIV_ROUND_UP(tclk_hz, 4);
	master->min_speed_hz = DIV_ROUND_UP(tclk_hz, 30);

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	spi->base = devm_ioremap_resource(&pdev->dev, r);
	if (IS_ERR(spi->base)) {
	status = PTR_ERR(spi->base);
	goto out_rel_clk;
	}

	if (orion_spi_reset(spi) < 0)
	goto out_rel_clk;

	master->dev.of_node = pdev->dev.of_node;
	status = devm_spi_register_master(&pdev->dev, master);
	if (status < 0)
	goto out_rel_clk;

	return status;

	out_rel_clk:
	clk_disable_unprepare(spi->clk);
	out:
	spi_master_put(master);
	return status;
	}


	static int orion_spi_remove(struct platform_device *pdev)
	{
	struct spi_master *master;
	struct orion_spi *spi;

	master = platform_get_drvdata(pdev);
	spi = spi_master_get_devdata(master);

	clk_disable_unprepare(spi->clk);

	return 0;
	}

	MODULE_ALIAS("platform:" DRIVER_NAME);

	static const struct of_device_id orion_spi_of_match_table[] = {
	{ .compatible = "marvell,orion-spi", },
	{}
	};
	MODULE_DEVICE_TABLE(of, orion_spi_of_match_table);

	static struct platform_driver orion_spi_driver = {
	.driver = {
	.name = DRIVER_NAME,
	.owner = THIS_MODULE,
	.of_match_table = of_match_ptr(orion_spi_of_match_table),
	},
	.probe = orion_spi_probe,
	.remove = orion_spi_remove,
	};

	module_platform_driver(orion_spi_driver);

	MODULE_DESCRIPTION("Orion SPI driver");
	MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
	MODULE_LICENSE("GPL");