drivers/nvmem/lpc18xx_eeprom.c - third_party/linux - Git at Google

 /*
  * NXP LPC18xx/LPC43xx EEPROM memory NVMEM driver
  *
  * Copyright (c) 2015 Ariel D'Alessandro <ariel@vanguardiasur.com>
  *
  * 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/device.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/nvmem-provider.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>

 /* Registers */
 #define LPC18XX_EEPROM_AUTOPROG			0x00c
 #define LPC18XX_EEPROM_AUTOPROG_WORD		0x1

 #define LPC18XX_EEPROM_CLKDIV			0x014

 #define LPC18XX_EEPROM_PWRDWN			0x018
 #define LPC18XX_EEPROM_PWRDWN_NO		0x0
 #define LPC18XX_EEPROM_PWRDWN_YES		0x1

 #define LPC18XX_EEPROM_INTSTAT			0xfe0
 #define LPC18XX_EEPROM_INTSTAT_END_OF_PROG	BIT(2)

 #define LPC18XX_EEPROM_INTSTATCLR		0xfe8
 #define LPC18XX_EEPROM_INTSTATCLR_PROG_CLR_ST	BIT(2)

 /* Fixed page size (bytes) */
 #define LPC18XX_EEPROM_PAGE_SIZE		0x80

 /* EEPROM device requires a ~1500 kHz clock (min 800 kHz, max 1600 kHz) */
 #define LPC18XX_EEPROM_CLOCK_HZ			1500000

 /* EEPROM requires 3 ms of erase/program time between each writing */
 #define LPC18XX_EEPROM_PROGRAM_TIME		3

 struct lpc18xx_eeprom_dev {
 	struct clk *clk;
 	void __iomem *reg_base;
 	void __iomem *mem_base;
 	struct nvmem_device *nvmem;
 	unsigned reg_bytes;
 	unsigned val_bytes;
 	int size;
 };

 static inline void lpc18xx_eeprom_writel(struct lpc18xx_eeprom_dev *eeprom,
 					 u32 reg, u32 val)
 {
 	writel(val, eeprom->reg_base + reg);
 }

 static inline u32 lpc18xx_eeprom_readl(struct lpc18xx_eeprom_dev *eeprom,
 				       u32 reg)
 {
 	return readl(eeprom->reg_base + reg);
 }

 static int lpc18xx_eeprom_busywait_until_prog(struct lpc18xx_eeprom_dev *eeprom)
 {
 	unsigned long end;
 	u32 val;

 	/* Wait until EEPROM program operation has finished */
 	end = jiffies + msecs_to_jiffies(LPC18XX_EEPROM_PROGRAM_TIME * 10);

 	while (time_is_after_jiffies(end)) {
 		val = lpc18xx_eeprom_readl(eeprom, LPC18XX_EEPROM_INTSTAT);

 		if (val & LPC18XX_EEPROM_INTSTAT_END_OF_PROG) {
 			lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_INTSTATCLR,
 					LPC18XX_EEPROM_INTSTATCLR_PROG_CLR_ST);
 			return 0;
 		}

 		usleep_range(LPC18XX_EEPROM_PROGRAM_TIME * USEC_PER_MSEC,
 			     (LPC18XX_EEPROM_PROGRAM_TIME + 1) * USEC_PER_MSEC);
 	}

 	return -ETIMEDOUT;
 }

 static int lpc18xx_eeprom_gather_write(void *context, unsigned int reg,
 				       void *val, size_t bytes)
 {
 	struct lpc18xx_eeprom_dev *eeprom = context;
 	unsigned int offset = reg;
 	int ret;

 	/*
 	 * The last page contains the EEPROM initialization data and is not
 	 * writable.
 	 */
 	if ((reg > eeprom->size - LPC18XX_EEPROM_PAGE_SIZE) ||
 			(reg + bytes > eeprom->size - LPC18XX_EEPROM_PAGE_SIZE))
 		return -EINVAL;


 	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
 			      LPC18XX_EEPROM_PWRDWN_NO);

 	/* Wait 100 us while the EEPROM wakes up */
 	usleep_range(100, 200);

 	while (bytes) {
 		writel(*(u32 *)val, eeprom->mem_base + offset);
 		ret = lpc18xx_eeprom_busywait_until_prog(eeprom);
 		if (ret < 0)
 			return ret;

 		bytes -= eeprom->val_bytes;
 		val += eeprom->val_bytes;
 		offset += eeprom->val_bytes;
 	}

 	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
 			      LPC18XX_EEPROM_PWRDWN_YES);

 	return 0;
 }

 static int lpc18xx_eeprom_read(void *context, unsigned int offset,
 			       void *val, size_t bytes)
 {
 	struct lpc18xx_eeprom_dev *eeprom = context;

 	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
 			      LPC18XX_EEPROM_PWRDWN_NO);

 	/* Wait 100 us while the EEPROM wakes up */
 	usleep_range(100, 200);

 	while (bytes) {
 		*(u32 *)val = readl(eeprom->mem_base + offset);
 		bytes -= eeprom->val_bytes;
 		val += eeprom->val_bytes;
 		offset += eeprom->val_bytes;
 	}

 	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
 			      LPC18XX_EEPROM_PWRDWN_YES);

 	return 0;
 }


 static struct nvmem_config lpc18xx_nvmem_config = {
 	.name = "lpc18xx-eeprom",
 	.stride = 4,
 	.word_size = 4,
 	.reg_read = lpc18xx_eeprom_read,
 	.reg_write = lpc18xx_eeprom_gather_write,
 };

 static int lpc18xx_eeprom_probe(struct platform_device *pdev)
 {
 	struct lpc18xx_eeprom_dev *eeprom;
 	struct device *dev = &pdev->dev;
 	struct reset_control *rst;
 	unsigned long clk_rate;
 	struct resource *res;
 	int ret;

 	eeprom = devm_kzalloc(dev, sizeof(*eeprom), GFP_KERNEL);
 	if (!eeprom)
 		return -ENOMEM;

 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "reg");
 	eeprom->reg_base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(eeprom->reg_base))
 		return PTR_ERR(eeprom->reg_base);

 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem");
 	eeprom->mem_base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(eeprom->mem_base))
 		return PTR_ERR(eeprom->mem_base);

 	eeprom->clk = devm_clk_get(&pdev->dev, "eeprom");
 	if (IS_ERR(eeprom->clk)) {
 		dev_err(&pdev->dev, "failed to get eeprom clock\n");
 		return PTR_ERR(eeprom->clk);
 	}

 	ret = clk_prepare_enable(eeprom->clk);
 	if (ret < 0) {
 		dev_err(dev, "failed to prepare/enable eeprom clk: %d\n", ret);
 		return ret;
 	}

 	rst = devm_reset_control_get_exclusive(dev, NULL);
 	if (IS_ERR(rst)) {
 		dev_err(dev, "failed to get reset: %ld\n", PTR_ERR(rst));
 		ret = PTR_ERR(rst);
 		goto err_clk;
 	}

 	ret = reset_control_assert(rst);
 	if (ret < 0) {
 		dev_err(dev, "failed to assert reset: %d\n", ret);
 		goto err_clk;
 	}

 	eeprom->val_bytes = 4;
 	eeprom->reg_bytes = 4;

 	/*
 	 * Clock rate is generated by dividing the system bus clock by the
 	 * division factor, contained in the divider register (minus 1 encoded).
 	 */
 	clk_rate = clk_get_rate(eeprom->clk);
 	clk_rate = DIV_ROUND_UP(clk_rate, LPC18XX_EEPROM_CLOCK_HZ) - 1;
 	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_CLKDIV, clk_rate);

 	/*
 	 * Writing a single word to the page will start the erase/program cycle
 	 * automatically
 	 */
 	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_AUTOPROG,
 			      LPC18XX_EEPROM_AUTOPROG_WORD);

 	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
 			      LPC18XX_EEPROM_PWRDWN_YES);

 	eeprom->size = resource_size(res);
 	lpc18xx_nvmem_config.size = resource_size(res);
 	lpc18xx_nvmem_config.dev = dev;
 	lpc18xx_nvmem_config.priv = eeprom;

 	eeprom->nvmem = nvmem_register(&lpc18xx_nvmem_config);
 	if (IS_ERR(eeprom->nvmem)) {
 		ret = PTR_ERR(eeprom->nvmem);
 		goto err_clk;
 	}

 	platform_set_drvdata(pdev, eeprom);

 	return 0;

 err_clk:
 	clk_disable_unprepare(eeprom->clk);

 	return ret;
 }

 static int lpc18xx_eeprom_remove(struct platform_device *pdev)
 {
 	struct lpc18xx_eeprom_dev *eeprom = platform_get_drvdata(pdev);
 	int ret;

 	ret = nvmem_unregister(eeprom->nvmem);
 	if (ret < 0)
 		return ret;

 	clk_disable_unprepare(eeprom->clk);

 	return 0;
 }

 static const struct of_device_id lpc18xx_eeprom_of_match[] = {
 	{ .compatible = "nxp,lpc1857-eeprom" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, lpc18xx_eeprom_of_match);

 static struct platform_driver lpc18xx_eeprom_driver = {
 	.probe = lpc18xx_eeprom_probe,
 	.remove = lpc18xx_eeprom_remove,
 	.driver = {
 		.name = "lpc18xx-eeprom",
 		.of_match_table = lpc18xx_eeprom_of_match,
 	},
 };

 module_platform_driver(lpc18xx_eeprom_driver);

 MODULE_AUTHOR("Ariel D'Alessandro <ariel@vanguardiasur.com.ar>");
 MODULE_DESCRIPTION("NXP LPC18xx EEPROM memory Driver");
 MODULE_LICENSE("GPL v2");
	/*
	* NXP LPC18xx/LPC43xx EEPROM memory NVMEM driver
	*
	* Copyright (c) 2015 Ariel D'Alessandro <ariel@vanguardiasur.com>
	*
	* 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/device.h>
	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/nvmem-provider.h>
	#include <linux/platform_device.h>
	#include <linux/reset.h>

	/* Registers */
	#define LPC18XX_EEPROM_AUTOPROG 0x00c
	#define LPC18XX_EEPROM_AUTOPROG_WORD 0x1

	#define LPC18XX_EEPROM_CLKDIV 0x014

	#define LPC18XX_EEPROM_PWRDWN 0x018
	#define LPC18XX_EEPROM_PWRDWN_NO 0x0
	#define LPC18XX_EEPROM_PWRDWN_YES 0x1

	#define LPC18XX_EEPROM_INTSTAT 0xfe0
	#define LPC18XX_EEPROM_INTSTAT_END_OF_PROG BIT(2)

	#define LPC18XX_EEPROM_INTSTATCLR 0xfe8
	#define LPC18XX_EEPROM_INTSTATCLR_PROG_CLR_ST BIT(2)

	/* Fixed page size (bytes) */
	#define LPC18XX_EEPROM_PAGE_SIZE 0x80

	/* EEPROM device requires a ~1500 kHz clock (min 800 kHz, max 1600 kHz) */
	#define LPC18XX_EEPROM_CLOCK_HZ 1500000

	/* EEPROM requires 3 ms of erase/program time between each writing */
	#define LPC18XX_EEPROM_PROGRAM_TIME 3

	struct lpc18xx_eeprom_dev {
	struct clk *clk;
	void __iomem *reg_base;
	void __iomem *mem_base;
	struct nvmem_device *nvmem;
	unsigned reg_bytes;
	unsigned val_bytes;
	int size;
	};

	static inline void lpc18xx_eeprom_writel(struct lpc18xx_eeprom_dev *eeprom,
	u32 reg, u32 val)
	{
	writel(val, eeprom->reg_base + reg);
	}

	static inline u32 lpc18xx_eeprom_readl(struct lpc18xx_eeprom_dev *eeprom,
	u32 reg)
	{
	return readl(eeprom->reg_base + reg);
	}

	static int lpc18xx_eeprom_busywait_until_prog(struct lpc18xx_eeprom_dev *eeprom)
	{
	unsigned long end;
	u32 val;

	/* Wait until EEPROM program operation has finished */
	end = jiffies + msecs_to_jiffies(LPC18XX_EEPROM_PROGRAM_TIME * 10);

	while (time_is_after_jiffies(end)) {
	val = lpc18xx_eeprom_readl(eeprom, LPC18XX_EEPROM_INTSTAT);

	if (val & LPC18XX_EEPROM_INTSTAT_END_OF_PROG) {
	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_INTSTATCLR,
	LPC18XX_EEPROM_INTSTATCLR_PROG_CLR_ST);
	return 0;
	}

	usleep_range(LPC18XX_EEPROM_PROGRAM_TIME * USEC_PER_MSEC,
	(LPC18XX_EEPROM_PROGRAM_TIME + 1) * USEC_PER_MSEC);
	}

	return -ETIMEDOUT;
	}

	static int lpc18xx_eeprom_gather_write(void *context, unsigned int reg,
	void *val, size_t bytes)
	{
	struct lpc18xx_eeprom_dev *eeprom = context;
	unsigned int offset = reg;
	int ret;

	/*
	* The last page contains the EEPROM initialization data and is not
	* writable.
	*/
	if ((reg > eeprom->size - LPC18XX_EEPROM_PAGE_SIZE) \|\|
	(reg + bytes > eeprom->size - LPC18XX_EEPROM_PAGE_SIZE))
	return -EINVAL;


	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
	LPC18XX_EEPROM_PWRDWN_NO);

	/* Wait 100 us while the EEPROM wakes up */
	usleep_range(100, 200);

	while (bytes) {
	writel((u32 )val, eeprom->mem_base + offset);
	ret = lpc18xx_eeprom_busywait_until_prog(eeprom);
	if (ret < 0)
	return ret;

	bytes -= eeprom->val_bytes;
	val += eeprom->val_bytes;
	offset += eeprom->val_bytes;
	}

	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
	LPC18XX_EEPROM_PWRDWN_YES);

	return 0;
	}

	static int lpc18xx_eeprom_read(void *context, unsigned int offset,
	void *val, size_t bytes)
	{
	struct lpc18xx_eeprom_dev *eeprom = context;

	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
	LPC18XX_EEPROM_PWRDWN_NO);

	/* Wait 100 us while the EEPROM wakes up */
	usleep_range(100, 200);

	while (bytes) {
	(u32 )val = readl(eeprom->mem_base + offset);
	bytes -= eeprom->val_bytes;
	val += eeprom->val_bytes;
	offset += eeprom->val_bytes;
	}

	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
	LPC18XX_EEPROM_PWRDWN_YES);

	return 0;
	}


	static struct nvmem_config lpc18xx_nvmem_config = {
	.name = "lpc18xx-eeprom",
	.stride = 4,
	.word_size = 4,
	.reg_read = lpc18xx_eeprom_read,
	.reg_write = lpc18xx_eeprom_gather_write,
	};

	static int lpc18xx_eeprom_probe(struct platform_device *pdev)
	{
	struct lpc18xx_eeprom_dev *eeprom;
	struct device *dev = &pdev->dev;
	struct reset_control *rst;
	unsigned long clk_rate;
	struct resource *res;
	int ret;

	eeprom = devm_kzalloc(dev, sizeof(*eeprom), GFP_KERNEL);
	if (!eeprom)
	return -ENOMEM;

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "reg");
	eeprom->reg_base = devm_ioremap_resource(dev, res);
	if (IS_ERR(eeprom->reg_base))
	return PTR_ERR(eeprom->reg_base);

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem");
	eeprom->mem_base = devm_ioremap_resource(dev, res);
	if (IS_ERR(eeprom->mem_base))
	return PTR_ERR(eeprom->mem_base);

	eeprom->clk = devm_clk_get(&pdev->dev, "eeprom");
	if (IS_ERR(eeprom->clk)) {
	dev_err(&pdev->dev, "failed to get eeprom clock\n");
	return PTR_ERR(eeprom->clk);
	}

	ret = clk_prepare_enable(eeprom->clk);
	if (ret < 0) {
	dev_err(dev, "failed to prepare/enable eeprom clk: %d\n", ret);
	return ret;
	}

	rst = devm_reset_control_get_exclusive(dev, NULL);
	if (IS_ERR(rst)) {
	dev_err(dev, "failed to get reset: %ld\n", PTR_ERR(rst));
	ret = PTR_ERR(rst);
	goto err_clk;
	}

	ret = reset_control_assert(rst);
	if (ret < 0) {
	dev_err(dev, "failed to assert reset: %d\n", ret);
	goto err_clk;
	}

	eeprom->val_bytes = 4;
	eeprom->reg_bytes = 4;

	/*
	* Clock rate is generated by dividing the system bus clock by the
	* division factor, contained in the divider register (minus 1 encoded).
	*/
	clk_rate = clk_get_rate(eeprom->clk);
	clk_rate = DIV_ROUND_UP(clk_rate, LPC18XX_EEPROM_CLOCK_HZ) - 1;
	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_CLKDIV, clk_rate);

	/*
	* Writing a single word to the page will start the erase/program cycle
	* automatically
	*/
	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_AUTOPROG,
	LPC18XX_EEPROM_AUTOPROG_WORD);

	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
	LPC18XX_EEPROM_PWRDWN_YES);

	eeprom->size = resource_size(res);
	lpc18xx_nvmem_config.size = resource_size(res);
	lpc18xx_nvmem_config.dev = dev;
	lpc18xx_nvmem_config.priv = eeprom;

	eeprom->nvmem = nvmem_register(&lpc18xx_nvmem_config);
	if (IS_ERR(eeprom->nvmem)) {
	ret = PTR_ERR(eeprom->nvmem);
	goto err_clk;
	}

	platform_set_drvdata(pdev, eeprom);

	return 0;

	err_clk:
	clk_disable_unprepare(eeprom->clk);

	return ret;
	}

	static int lpc18xx_eeprom_remove(struct platform_device *pdev)
	{
	struct lpc18xx_eeprom_dev *eeprom = platform_get_drvdata(pdev);
	int ret;

	ret = nvmem_unregister(eeprom->nvmem);
	if (ret < 0)
	return ret;

	clk_disable_unprepare(eeprom->clk);

	return 0;
	}

	static const struct of_device_id lpc18xx_eeprom_of_match[] = {
	{ .compatible = "nxp,lpc1857-eeprom" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, lpc18xx_eeprom_of_match);

	static struct platform_driver lpc18xx_eeprom_driver = {
	.probe = lpc18xx_eeprom_probe,
	.remove = lpc18xx_eeprom_remove,
	.driver = {
	.name = "lpc18xx-eeprom",
	.of_match_table = lpc18xx_eeprom_of_match,
	},
	};

	module_platform_driver(lpc18xx_eeprom_driver);

	MODULE_AUTHOR("Ariel D'Alessandro <ariel@vanguardiasur.com.ar>");
	MODULE_DESCRIPTION("NXP LPC18xx EEPROM memory Driver");
	MODULE_LICENSE("GPL v2");