drivers/mtd/spi-nor/nxp-spifi.c - third_party/dump-capture-kernel - Git at Google

 /*
  * SPI-NOR driver for NXP SPI Flash Interface (SPIFI)
  *
  * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
  *
  * Based on Freescale QuadSPI driver:
  * Copyright (C) 2013 Freescale Semiconductor, Inc.
  *
  * 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/clk.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
 #include <linux/mtd/spi-nor.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/spi/spi.h>

 /* NXP SPIFI registers, bits and macros */
 #define SPIFI_CTRL				0x000
 #define  SPIFI_CTRL_TIMEOUT(timeout)		(timeout)
 #define  SPIFI_CTRL_CSHIGH(cshigh)		((cshigh) << 16)
 #define  SPIFI_CTRL_MODE3			BIT(23)
 #define  SPIFI_CTRL_DUAL			BIT(28)
 #define  SPIFI_CTRL_FBCLK			BIT(30)
 #define SPIFI_CMD				0x004
 #define  SPIFI_CMD_DATALEN(dlen)		((dlen) & 0x3fff)
 #define  SPIFI_CMD_DOUT				BIT(15)
 #define  SPIFI_CMD_INTLEN(ilen)			((ilen) << 16)
 #define  SPIFI_CMD_FIELDFORM(field)		((field) << 19)
 #define  SPIFI_CMD_FIELDFORM_ALL_SERIAL		SPIFI_CMD_FIELDFORM(0x0)
 #define  SPIFI_CMD_FIELDFORM_QUAD_DUAL_DATA	SPIFI_CMD_FIELDFORM(0x1)
 #define  SPIFI_CMD_FRAMEFORM(frame)		((frame) << 21)
 #define  SPIFI_CMD_FRAMEFORM_OPCODE_ONLY	SPIFI_CMD_FRAMEFORM(0x1)
 #define  SPIFI_CMD_OPCODE(op)			((op) << 24)
 #define SPIFI_ADDR				0x008
 #define SPIFI_IDATA				0x00c
 #define SPIFI_CLIMIT				0x010
 #define SPIFI_DATA				0x014
 #define SPIFI_MCMD				0x018
 #define SPIFI_STAT				0x01c
 #define  SPIFI_STAT_MCINIT			BIT(0)
 #define  SPIFI_STAT_CMD				BIT(1)
 #define  SPIFI_STAT_RESET			BIT(4)

 #define SPI_NOR_MAX_ID_LEN	6

 struct nxp_spifi {
 	struct device *dev;
 	struct clk *clk_spifi;
 	struct clk *clk_reg;
 	void __iomem *io_base;
 	void __iomem *flash_base;
 	struct spi_nor nor;
 	bool memory_mode;
 	u32 mcmd;
 };

 static int nxp_spifi_wait_for_cmd(struct nxp_spifi *spifi)
 {
 	u8 stat;
 	int ret;

 	ret = readb_poll_timeout(spifi->io_base + SPIFI_STAT, stat,
 				 !(stat & SPIFI_STAT_CMD), 10, 30);
 	if (ret)
 		dev_warn(spifi->dev, "command timed out\n");

 	return ret;
 }

 static int nxp_spifi_reset(struct nxp_spifi *spifi)
 {
 	u8 stat;
 	int ret;

 	writel(SPIFI_STAT_RESET, spifi->io_base + SPIFI_STAT);
 	ret = readb_poll_timeout(spifi->io_base + SPIFI_STAT, stat,
 				 !(stat & SPIFI_STAT_RESET), 10, 30);
 	if (ret)
 		dev_warn(spifi->dev, "state reset timed out\n");

 	return ret;
 }

 static int nxp_spifi_set_memory_mode_off(struct nxp_spifi *spifi)
 {
 	int ret;

 	if (!spifi->memory_mode)
 		return 0;

 	ret = nxp_spifi_reset(spifi);
 	if (ret)
 		dev_err(spifi->dev, "unable to enter command mode\n");
 	else
 		spifi->memory_mode = false;

 	return ret;
 }

 static int nxp_spifi_set_memory_mode_on(struct nxp_spifi *spifi)
 {
 	u8 stat;
 	int ret;

 	if (spifi->memory_mode)
 		return 0;

 	writel(spifi->mcmd, spifi->io_base + SPIFI_MCMD);
 	ret = readb_poll_timeout(spifi->io_base + SPIFI_STAT, stat,
 				 stat & SPIFI_STAT_MCINIT, 10, 30);
 	if (ret)
 		dev_err(spifi->dev, "unable to enter memory mode\n");
 	else
 		spifi->memory_mode = true;

 	return ret;
 }

 static int nxp_spifi_read_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
 {
 	struct nxp_spifi *spifi = nor->priv;
 	u32 cmd;
 	int ret;

 	ret = nxp_spifi_set_memory_mode_off(spifi);
 	if (ret)
 		return ret;

 	cmd = SPIFI_CMD_DATALEN(len) |
 	      SPIFI_CMD_OPCODE(opcode) |
 	      SPIFI_CMD_FIELDFORM_ALL_SERIAL |
 	      SPIFI_CMD_FRAMEFORM_OPCODE_ONLY;
 	writel(cmd, spifi->io_base + SPIFI_CMD);

 	while (len--)
 		*buf++ = readb(spifi->io_base + SPIFI_DATA);

 	return nxp_spifi_wait_for_cmd(spifi);
 }

 static int nxp_spifi_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
 {
 	struct nxp_spifi *spifi = nor->priv;
 	u32 cmd;
 	int ret;

 	ret = nxp_spifi_set_memory_mode_off(spifi);
 	if (ret)
 		return ret;

 	cmd = SPIFI_CMD_DOUT |
 	      SPIFI_CMD_DATALEN(len) |
 	      SPIFI_CMD_OPCODE(opcode) |
 	      SPIFI_CMD_FIELDFORM_ALL_SERIAL |
 	      SPIFI_CMD_FRAMEFORM_OPCODE_ONLY;
 	writel(cmd, spifi->io_base + SPIFI_CMD);

 	while (len--)
 		writeb(*buf++, spifi->io_base + SPIFI_DATA);

 	return nxp_spifi_wait_for_cmd(spifi);
 }

 static ssize_t nxp_spifi_read(struct spi_nor *nor, loff_t from, size_t len,
 			      u_char *buf)
 {
 	struct nxp_spifi *spifi = nor->priv;
 	int ret;

 	ret = nxp_spifi_set_memory_mode_on(spifi);
 	if (ret)
 		return ret;

 	memcpy_fromio(buf, spifi->flash_base + from, len);

 	return len;
 }

 static ssize_t nxp_spifi_write(struct spi_nor *nor, loff_t to, size_t len,
 			       const u_char *buf)
 {
 	struct nxp_spifi *spifi = nor->priv;
 	u32 cmd;
 	int ret;
 	size_t i;

 	ret = nxp_spifi_set_memory_mode_off(spifi);
 	if (ret)
 		return ret;

 	writel(to, spifi->io_base + SPIFI_ADDR);

 	cmd = SPIFI_CMD_DOUT |
 	      SPIFI_CMD_DATALEN(len) |
 	      SPIFI_CMD_FIELDFORM_ALL_SERIAL |
 	      SPIFI_CMD_OPCODE(nor->program_opcode) |
 	      SPIFI_CMD_FRAMEFORM(spifi->nor.addr_width + 1);
 	writel(cmd, spifi->io_base + SPIFI_CMD);

 	for (i = 0; i < len; i++)
 		writeb(buf[i], spifi->io_base + SPIFI_DATA);

 	ret = nxp_spifi_wait_for_cmd(spifi);
 	if (ret)
 		return ret;

 	return len;
 }

 static int nxp_spifi_erase(struct spi_nor *nor, loff_t offs)
 {
 	struct nxp_spifi *spifi = nor->priv;
 	u32 cmd;
 	int ret;

 	ret = nxp_spifi_set_memory_mode_off(spifi);
 	if (ret)
 		return ret;

 	writel(offs, spifi->io_base + SPIFI_ADDR);

 	cmd = SPIFI_CMD_FIELDFORM_ALL_SERIAL |
 	      SPIFI_CMD_OPCODE(nor->erase_opcode) |
 	      SPIFI_CMD_FRAMEFORM(spifi->nor.addr_width + 1);
 	writel(cmd, spifi->io_base + SPIFI_CMD);

 	return nxp_spifi_wait_for_cmd(spifi);
 }

 static int nxp_spifi_setup_memory_cmd(struct nxp_spifi *spifi)
 {
 	switch (spifi->nor.read_proto) {
 	case SNOR_PROTO_1_1_1:
 		spifi->mcmd = SPIFI_CMD_FIELDFORM_ALL_SERIAL;
 		break;
 	case SNOR_PROTO_1_1_2:
 	case SNOR_PROTO_1_1_4:
 		spifi->mcmd = SPIFI_CMD_FIELDFORM_QUAD_DUAL_DATA;
 		break;
 	default:
 		dev_err(spifi->dev, "unsupported SPI read mode\n");
 		return -EINVAL;
 	}

 	/* Memory mode supports address length between 1 and 4 */
 	if (spifi->nor.addr_width < 1 || spifi->nor.addr_width > 4)
 		return -EINVAL;

 	spifi->mcmd |= SPIFI_CMD_OPCODE(spifi->nor.read_opcode) |
 		       SPIFI_CMD_INTLEN(spifi->nor.read_dummy / 8) |
 		       SPIFI_CMD_FRAMEFORM(spifi->nor.addr_width + 1);

 	return 0;
 }

 static void nxp_spifi_dummy_id_read(struct spi_nor *nor)
 {
 	u8 id[SPI_NOR_MAX_ID_LEN];
 	nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
 }

 static int nxp_spifi_setup_flash(struct nxp_spifi *spifi,
 				 struct device_node *np)
 {
 	struct spi_nor_hwcaps hwcaps = {
 		.mask = SNOR_HWCAPS_READ |
 			SNOR_HWCAPS_READ_FAST |
 			SNOR_HWCAPS_PP,
 	};
 	u32 ctrl, property;
 	u16 mode = 0;
 	int ret;

 	if (!of_property_read_u32(np, "spi-rx-bus-width", &property)) {
 		switch (property) {
 		case 1:
 			break;
 		case 2:
 			mode |= SPI_RX_DUAL;
 			break;
 		case 4:
 			mode |= SPI_RX_QUAD;
 			break;
 		default:
 			dev_err(spifi->dev, "unsupported rx-bus-width\n");
 			return -EINVAL;
 		}
 	}

 	if (of_find_property(np, "spi-cpha", NULL))
 		mode |= SPI_CPHA;

 	if (of_find_property(np, "spi-cpol", NULL))
 		mode |= SPI_CPOL;

 	/* Setup control register defaults */
 	ctrl = SPIFI_CTRL_TIMEOUT(1000) |
 	       SPIFI_CTRL_CSHIGH(15) |
 	       SPIFI_CTRL_FBCLK;

 	if (mode & SPI_RX_DUAL) {
 		ctrl |= SPIFI_CTRL_DUAL;
 		hwcaps.mask |= SNOR_HWCAPS_READ_1_1_2;
 	} else if (mode & SPI_RX_QUAD) {
 		ctrl &= ~SPIFI_CTRL_DUAL;
 		hwcaps.mask |= SNOR_HWCAPS_READ_1_1_4;
 	} else {
 		ctrl |= SPIFI_CTRL_DUAL;
 	}

 	switch (mode & (SPI_CPHA | SPI_CPOL)) {
 	case SPI_MODE_0:
 		ctrl &= ~SPIFI_CTRL_MODE3;
 		break;
 	case SPI_MODE_3:
 		ctrl |= SPIFI_CTRL_MODE3;
 		break;
 	default:
 		dev_err(spifi->dev, "only mode 0 and 3 supported\n");
 		return -EINVAL;
 	}

 	writel(ctrl, spifi->io_base + SPIFI_CTRL);

 	spifi->nor.dev   = spifi->dev;
 	spi_nor_set_flash_node(&spifi->nor, np);
 	spifi->nor.priv  = spifi;
 	spifi->nor.read  = nxp_spifi_read;
 	spifi->nor.write = nxp_spifi_write;
 	spifi->nor.erase = nxp_spifi_erase;
 	spifi->nor.read_reg  = nxp_spifi_read_reg;
 	spifi->nor.write_reg = nxp_spifi_write_reg;

 	/*
 	 * The first read on a hard reset isn't reliable so do a
 	 * dummy read of the id before calling spi_nor_scan().
 	 * The reason for this problem is unknown.
 	 *
 	 * The official NXP spifilib uses more or less the same
 	 * workaround that is applied here by reading the device
 	 * id multiple times.
 	 */
 	nxp_spifi_dummy_id_read(&spifi->nor);

 	ret = spi_nor_scan(&spifi->nor, NULL, &hwcaps);
 	if (ret) {
 		dev_err(spifi->dev, "device scan failed\n");
 		return ret;
 	}

 	ret = nxp_spifi_setup_memory_cmd(spifi);
 	if (ret) {
 		dev_err(spifi->dev, "memory command setup failed\n");
 		return ret;
 	}

 	ret = mtd_device_register(&spifi->nor.mtd, NULL, 0);
 	if (ret) {
 		dev_err(spifi->dev, "mtd device parse failed\n");
 		return ret;
 	}

 	return 0;
 }

 static int nxp_spifi_probe(struct platform_device *pdev)
 {
 	struct device_node *flash_np;
 	struct nxp_spifi *spifi;
 	struct resource *res;
 	int ret;

 	spifi = devm_kzalloc(&pdev->dev, sizeof(*spifi), GFP_KERNEL);
 	if (!spifi)
 		return -ENOMEM;

 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "spifi");
 	spifi->io_base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(spifi->io_base))
 		return PTR_ERR(spifi->io_base);

 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "flash");
 	spifi->flash_base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(spifi->flash_base))
 		return PTR_ERR(spifi->flash_base);

 	spifi->clk_spifi = devm_clk_get(&pdev->dev, "spifi");
 	if (IS_ERR(spifi->clk_spifi)) {
 		dev_err(&pdev->dev, "spifi clock not found\n");
 		return PTR_ERR(spifi->clk_spifi);
 	}

 	spifi->clk_reg = devm_clk_get(&pdev->dev, "reg");
 	if (IS_ERR(spifi->clk_reg)) {
 		dev_err(&pdev->dev, "reg clock not found\n");
 		return PTR_ERR(spifi->clk_reg);
 	}

 	ret = clk_prepare_enable(spifi->clk_reg);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to enable reg clock\n");
 		return ret;
 	}

 	ret = clk_prepare_enable(spifi->clk_spifi);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to enable spifi clock\n");
 		goto dis_clk_reg;
 	}

 	spifi->dev = &pdev->dev;
 	platform_set_drvdata(pdev, spifi);

 	/* Initialize and reset device */
 	nxp_spifi_reset(spifi);
 	writel(0, spifi->io_base + SPIFI_IDATA);
 	writel(0, spifi->io_base + SPIFI_MCMD);
 	nxp_spifi_reset(spifi);

 	flash_np = of_get_next_available_child(pdev->dev.of_node, NULL);
 	if (!flash_np) {
 		dev_err(&pdev->dev, "no SPI flash device to configure\n");
 		ret = -ENODEV;
 		goto dis_clks;
 	}

 	ret = nxp_spifi_setup_flash(spifi, flash_np);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to setup flash chip\n");
 		goto dis_clks;
 	}

 	return 0;

 dis_clks:
 	clk_disable_unprepare(spifi->clk_spifi);
 dis_clk_reg:
 	clk_disable_unprepare(spifi->clk_reg);
 	return ret;
 }

 static int nxp_spifi_remove(struct platform_device *pdev)
 {
 	struct nxp_spifi *spifi = platform_get_drvdata(pdev);

 	mtd_device_unregister(&spifi->nor.mtd);
 	clk_disable_unprepare(spifi->clk_spifi);
 	clk_disable_unprepare(spifi->clk_reg);

 	return 0;
 }

 static const struct of_device_id nxp_spifi_match[] = {
 	{.compatible = "nxp,lpc1773-spifi"},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, nxp_spifi_match);

 static struct platform_driver nxp_spifi_driver = {
 	.probe	= nxp_spifi_probe,
 	.remove	= nxp_spifi_remove,
 	.driver	= {
 		.name = "nxp-spifi",
 		.of_match_table = nxp_spifi_match,
 	},
 };
 module_platform_driver(nxp_spifi_driver);

 MODULE_DESCRIPTION("NXP SPI Flash Interface driver");
 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
 MODULE_LICENSE("GPL v2");
	/*
	* SPI-NOR driver for NXP SPI Flash Interface (SPIFI)
	*
	* Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
	*
	* Based on Freescale QuadSPI driver:
	* Copyright (C) 2013 Freescale Semiconductor, Inc.
	*
	* 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/clk.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/iopoll.h>
	#include <linux/module.h>
	#include <linux/mtd/mtd.h>
	#include <linux/mtd/partitions.h>
	#include <linux/mtd/spi-nor.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/spi/spi.h>

	/* NXP SPIFI registers, bits and macros */
	#define SPIFI_CTRL 0x000
	#define SPIFI_CTRL_TIMEOUT(timeout) (timeout)
	#define SPIFI_CTRL_CSHIGH(cshigh) ((cshigh) << 16)
	#define SPIFI_CTRL_MODE3 BIT(23)
	#define SPIFI_CTRL_DUAL BIT(28)
	#define SPIFI_CTRL_FBCLK BIT(30)
	#define SPIFI_CMD 0x004
	#define SPIFI_CMD_DATALEN(dlen) ((dlen) & 0x3fff)
	#define SPIFI_CMD_DOUT BIT(15)
	#define SPIFI_CMD_INTLEN(ilen) ((ilen) << 16)
	#define SPIFI_CMD_FIELDFORM(field) ((field) << 19)
	#define SPIFI_CMD_FIELDFORM_ALL_SERIAL SPIFI_CMD_FIELDFORM(0x0)
	#define SPIFI_CMD_FIELDFORM_QUAD_DUAL_DATA SPIFI_CMD_FIELDFORM(0x1)
	#define SPIFI_CMD_FRAMEFORM(frame) ((frame) << 21)
	#define SPIFI_CMD_FRAMEFORM_OPCODE_ONLY SPIFI_CMD_FRAMEFORM(0x1)
	#define SPIFI_CMD_OPCODE(op) ((op) << 24)
	#define SPIFI_ADDR 0x008
	#define SPIFI_IDATA 0x00c
	#define SPIFI_CLIMIT 0x010
	#define SPIFI_DATA 0x014
	#define SPIFI_MCMD 0x018
	#define SPIFI_STAT 0x01c
	#define SPIFI_STAT_MCINIT BIT(0)
	#define SPIFI_STAT_CMD BIT(1)
	#define SPIFI_STAT_RESET BIT(4)

	#define SPI_NOR_MAX_ID_LEN 6

	struct nxp_spifi {
	struct device *dev;
	struct clk *clk_spifi;
	struct clk *clk_reg;
	void __iomem *io_base;
	void __iomem *flash_base;
	struct spi_nor nor;
	bool memory_mode;
	u32 mcmd;
	};

	static int nxp_spifi_wait_for_cmd(struct nxp_spifi *spifi)
	{
	u8 stat;
	int ret;

	ret = readb_poll_timeout(spifi->io_base + SPIFI_STAT, stat,
	!(stat & SPIFI_STAT_CMD), 10, 30);
	if (ret)
	dev_warn(spifi->dev, "command timed out\n");

	return ret;
	}

	static int nxp_spifi_reset(struct nxp_spifi *spifi)
	{
	u8 stat;
	int ret;

	writel(SPIFI_STAT_RESET, spifi->io_base + SPIFI_STAT);
	ret = readb_poll_timeout(spifi->io_base + SPIFI_STAT, stat,
	!(stat & SPIFI_STAT_RESET), 10, 30);
	if (ret)
	dev_warn(spifi->dev, "state reset timed out\n");

	return ret;
	}

	static int nxp_spifi_set_memory_mode_off(struct nxp_spifi *spifi)
	{
	int ret;

	if (!spifi->memory_mode)
	return 0;

	ret = nxp_spifi_reset(spifi);
	if (ret)
	dev_err(spifi->dev, "unable to enter command mode\n");
	else
	spifi->memory_mode = false;

	return ret;
	}

	static int nxp_spifi_set_memory_mode_on(struct nxp_spifi *spifi)
	{
	u8 stat;
	int ret;

	if (spifi->memory_mode)
	return 0;

	writel(spifi->mcmd, spifi->io_base + SPIFI_MCMD);
	ret = readb_poll_timeout(spifi->io_base + SPIFI_STAT, stat,
	stat & SPIFI_STAT_MCINIT, 10, 30);
	if (ret)
	dev_err(spifi->dev, "unable to enter memory mode\n");
	else
	spifi->memory_mode = true;

	return ret;
	}

	static int nxp_spifi_read_reg(struct spi_nor nor, u8 opcode, u8 buf, int len)
	{
	struct nxp_spifi *spifi = nor->priv;
	u32 cmd;
	int ret;

	ret = nxp_spifi_set_memory_mode_off(spifi);
	if (ret)
	return ret;

	cmd = SPIFI_CMD_DATALEN(len) \|
	SPIFI_CMD_OPCODE(opcode) \|
	SPIFI_CMD_FIELDFORM_ALL_SERIAL \|
	SPIFI_CMD_FRAMEFORM_OPCODE_ONLY;
	writel(cmd, spifi->io_base + SPIFI_CMD);

	while (len--)
	*buf++ = readb(spifi->io_base + SPIFI_DATA);

	return nxp_spifi_wait_for_cmd(spifi);
	}

	static int nxp_spifi_write_reg(struct spi_nor nor, u8 opcode, u8 buf, int len)
	{
	struct nxp_spifi *spifi = nor->priv;
	u32 cmd;
	int ret;

	ret = nxp_spifi_set_memory_mode_off(spifi);
	if (ret)
	return ret;

	cmd = SPIFI_CMD_DOUT \|
	SPIFI_CMD_DATALEN(len) \|
	SPIFI_CMD_OPCODE(opcode) \|
	SPIFI_CMD_FIELDFORM_ALL_SERIAL \|
	SPIFI_CMD_FRAMEFORM_OPCODE_ONLY;
	writel(cmd, spifi->io_base + SPIFI_CMD);

	while (len--)
	writeb(*buf++, spifi->io_base + SPIFI_DATA);

	return nxp_spifi_wait_for_cmd(spifi);
	}

	static ssize_t nxp_spifi_read(struct spi_nor *nor, loff_t from, size_t len,
	u_char *buf)
	{
	struct nxp_spifi *spifi = nor->priv;
	int ret;

	ret = nxp_spifi_set_memory_mode_on(spifi);
	if (ret)
	return ret;

	memcpy_fromio(buf, spifi->flash_base + from, len);

	return len;
	}

	static ssize_t nxp_spifi_write(struct spi_nor *nor, loff_t to, size_t len,
	const u_char *buf)
	{
	struct nxp_spifi *spifi = nor->priv;
	u32 cmd;
	int ret;
	size_t i;

	ret = nxp_spifi_set_memory_mode_off(spifi);
	if (ret)
	return ret;

	writel(to, spifi->io_base + SPIFI_ADDR);

	cmd = SPIFI_CMD_DOUT \|
	SPIFI_CMD_DATALEN(len) \|
	SPIFI_CMD_FIELDFORM_ALL_SERIAL \|
	SPIFI_CMD_OPCODE(nor->program_opcode) \|
	SPIFI_CMD_FRAMEFORM(spifi->nor.addr_width + 1);
	writel(cmd, spifi->io_base + SPIFI_CMD);

	for (i = 0; i < len; i++)
	writeb(buf[i], spifi->io_base + SPIFI_DATA);

	ret = nxp_spifi_wait_for_cmd(spifi);
	if (ret)
	return ret;

	return len;
	}

	static int nxp_spifi_erase(struct spi_nor *nor, loff_t offs)
	{
	struct nxp_spifi *spifi = nor->priv;
	u32 cmd;
	int ret;

	ret = nxp_spifi_set_memory_mode_off(spifi);
	if (ret)
	return ret;

	writel(offs, spifi->io_base + SPIFI_ADDR);

	cmd = SPIFI_CMD_FIELDFORM_ALL_SERIAL \|
	SPIFI_CMD_OPCODE(nor->erase_opcode) \|
	SPIFI_CMD_FRAMEFORM(spifi->nor.addr_width + 1);
	writel(cmd, spifi->io_base + SPIFI_CMD);

	return nxp_spifi_wait_for_cmd(spifi);
	}

	static int nxp_spifi_setup_memory_cmd(struct nxp_spifi *spifi)
	{
	switch (spifi->nor.read_proto) {
	case SNOR_PROTO_1_1_1:
	spifi->mcmd = SPIFI_CMD_FIELDFORM_ALL_SERIAL;
	break;
	case SNOR_PROTO_1_1_2:
	case SNOR_PROTO_1_1_4:
	spifi->mcmd = SPIFI_CMD_FIELDFORM_QUAD_DUAL_DATA;
	break;
	default:
	dev_err(spifi->dev, "unsupported SPI read mode\n");
	return -EINVAL;
	}

	/* Memory mode supports address length between 1 and 4 */
	if (spifi->nor.addr_width < 1 \|\| spifi->nor.addr_width > 4)
	return -EINVAL;

	spifi->mcmd \|= SPIFI_CMD_OPCODE(spifi->nor.read_opcode) \|
	SPIFI_CMD_INTLEN(spifi->nor.read_dummy / 8) \|
	SPIFI_CMD_FRAMEFORM(spifi->nor.addr_width + 1);

	return 0;
	}

	static void nxp_spifi_dummy_id_read(struct spi_nor *nor)
	{
	u8 id[SPI_NOR_MAX_ID_LEN];
	nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
	}

	static int nxp_spifi_setup_flash(struct nxp_spifi *spifi,
	struct device_node *np)
	{
	struct spi_nor_hwcaps hwcaps = {
	.mask = SNOR_HWCAPS_READ \|
	SNOR_HWCAPS_READ_FAST \|
	SNOR_HWCAPS_PP,
	};
	u32 ctrl, property;
	u16 mode = 0;
	int ret;

	if (!of_property_read_u32(np, "spi-rx-bus-width", &property)) {
	switch (property) {
	case 1:
	break;
	case 2:
	mode \|= SPI_RX_DUAL;
	break;
	case 4:
	mode \|= SPI_RX_QUAD;
	break;
	default:
	dev_err(spifi->dev, "unsupported rx-bus-width\n");
	return -EINVAL;
	}
	}

	if (of_find_property(np, "spi-cpha", NULL))
	mode \|= SPI_CPHA;

	if (of_find_property(np, "spi-cpol", NULL))
	mode \|= SPI_CPOL;

	/* Setup control register defaults */
	ctrl = SPIFI_CTRL_TIMEOUT(1000) \|
	SPIFI_CTRL_CSHIGH(15) \|
	SPIFI_CTRL_FBCLK;

	if (mode & SPI_RX_DUAL) {
	ctrl \|= SPIFI_CTRL_DUAL;
	hwcaps.mask \|= SNOR_HWCAPS_READ_1_1_2;
	} else if (mode & SPI_RX_QUAD) {
	ctrl &= ~SPIFI_CTRL_DUAL;
	hwcaps.mask \|= SNOR_HWCAPS_READ_1_1_4;
	} else {
	ctrl \|= SPIFI_CTRL_DUAL;
	}

	switch (mode & (SPI_CPHA \| SPI_CPOL)) {
	case SPI_MODE_0:
	ctrl &= ~SPIFI_CTRL_MODE3;
	break;
	case SPI_MODE_3:
	ctrl \|= SPIFI_CTRL_MODE3;
	break;
	default:
	dev_err(spifi->dev, "only mode 0 and 3 supported\n");
	return -EINVAL;
	}

	writel(ctrl, spifi->io_base + SPIFI_CTRL);

	spifi->nor.dev = spifi->dev;
	spi_nor_set_flash_node(&spifi->nor, np);
	spifi->nor.priv = spifi;
	spifi->nor.read = nxp_spifi_read;
	spifi->nor.write = nxp_spifi_write;
	spifi->nor.erase = nxp_spifi_erase;
	spifi->nor.read_reg = nxp_spifi_read_reg;
	spifi->nor.write_reg = nxp_spifi_write_reg;

	/*
	* The first read on a hard reset isn't reliable so do a
	* dummy read of the id before calling spi_nor_scan().
	* The reason for this problem is unknown.
	*
	* The official NXP spifilib uses more or less the same
	* workaround that is applied here by reading the device
	* id multiple times.
	*/
	nxp_spifi_dummy_id_read(&spifi->nor);

	ret = spi_nor_scan(&spifi->nor, NULL, &hwcaps);
	if (ret) {
	dev_err(spifi->dev, "device scan failed\n");
	return ret;
	}

	ret = nxp_spifi_setup_memory_cmd(spifi);
	if (ret) {
	dev_err(spifi->dev, "memory command setup failed\n");
	return ret;
	}

	ret = mtd_device_register(&spifi->nor.mtd, NULL, 0);
	if (ret) {
	dev_err(spifi->dev, "mtd device parse failed\n");
	return ret;
	}

	return 0;
	}

	static int nxp_spifi_probe(struct platform_device *pdev)
	{
	struct device_node *flash_np;
	struct nxp_spifi *spifi;
	struct resource *res;
	int ret;

	spifi = devm_kzalloc(&pdev->dev, sizeof(*spifi), GFP_KERNEL);
	if (!spifi)
	return -ENOMEM;

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "spifi");
	spifi->io_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(spifi->io_base))
	return PTR_ERR(spifi->io_base);

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "flash");
	spifi->flash_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(spifi->flash_base))
	return PTR_ERR(spifi->flash_base);

	spifi->clk_spifi = devm_clk_get(&pdev->dev, "spifi");
	if (IS_ERR(spifi->clk_spifi)) {
	dev_err(&pdev->dev, "spifi clock not found\n");
	return PTR_ERR(spifi->clk_spifi);
	}

	spifi->clk_reg = devm_clk_get(&pdev->dev, "reg");
	if (IS_ERR(spifi->clk_reg)) {
	dev_err(&pdev->dev, "reg clock not found\n");
	return PTR_ERR(spifi->clk_reg);
	}

	ret = clk_prepare_enable(spifi->clk_reg);
	if (ret) {
	dev_err(&pdev->dev, "unable to enable reg clock\n");
	return ret;
	}

	ret = clk_prepare_enable(spifi->clk_spifi);
	if (ret) {
	dev_err(&pdev->dev, "unable to enable spifi clock\n");
	goto dis_clk_reg;
	}

	spifi->dev = &pdev->dev;
	platform_set_drvdata(pdev, spifi);

	/* Initialize and reset device */
	nxp_spifi_reset(spifi);
	writel(0, spifi->io_base + SPIFI_IDATA);
	writel(0, spifi->io_base + SPIFI_MCMD);
	nxp_spifi_reset(spifi);

	flash_np = of_get_next_available_child(pdev->dev.of_node, NULL);
	if (!flash_np) {
	dev_err(&pdev->dev, "no SPI flash device to configure\n");
	ret = -ENODEV;
	goto dis_clks;
	}

	ret = nxp_spifi_setup_flash(spifi, flash_np);
	if (ret) {
	dev_err(&pdev->dev, "unable to setup flash chip\n");
	goto dis_clks;
	}

	return 0;

	dis_clks:
	clk_disable_unprepare(spifi->clk_spifi);
	dis_clk_reg:
	clk_disable_unprepare(spifi->clk_reg);
	return ret;
	}

	static int nxp_spifi_remove(struct platform_device *pdev)
	{
	struct nxp_spifi *spifi = platform_get_drvdata(pdev);

	mtd_device_unregister(&spifi->nor.mtd);
	clk_disable_unprepare(spifi->clk_spifi);
	clk_disable_unprepare(spifi->clk_reg);

	return 0;
	}

	static const struct of_device_id nxp_spifi_match[] = {
	{.compatible = "nxp,lpc1773-spifi"},
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, nxp_spifi_match);

	static struct platform_driver nxp_spifi_driver = {
	.probe = nxp_spifi_probe,
	.remove = nxp_spifi_remove,
	.driver = {
	.name = "nxp-spifi",
	.of_match_table = nxp_spifi_match,
	},
	};
	module_platform_driver(nxp_spifi_driver);

	MODULE_DESCRIPTION("NXP SPI Flash Interface driver");
	MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
	MODULE_LICENSE("GPL v2");