drivers/rtc/rtc-ds2404.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (C) 2012 Sven Schnelle <svens@stackframe.org>
  *
  * 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/platform_device.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/rtc.h>
 #include <linux/types.h>
 #include <linux/bcd.h>
 #include <linux/rtc-ds2404.h>
 #include <linux/delay.h>
 #include <linux/gpio.h>
 #include <linux/slab.h>

 #include <linux/io.h>

 #define DS2404_STATUS_REG 0x200
 #define DS2404_CONTROL_REG 0x201
 #define DS2404_RTC_REG 0x202

 #define DS2404_WRITE_SCRATCHPAD_CMD 0x0f
 #define DS2404_READ_SCRATCHPAD_CMD 0xaa
 #define DS2404_COPY_SCRATCHPAD_CMD 0x55
 #define DS2404_READ_MEMORY_CMD 0xf0

 struct ds2404;

 struct ds2404_chip_ops {
 	int (*map_io)(struct ds2404 *chip, struct platform_device *pdev,
 		      struct ds2404_platform_data *pdata);
 	void (*unmap_io)(struct ds2404 *chip);
 };

 #define DS2404_RST	0
 #define DS2404_CLK	1
 #define DS2404_DQ	2

 struct ds2404_gpio {
 	const char *name;
 	unsigned int gpio;
 };

 struct ds2404 {
 	struct ds2404_gpio *gpio;
 	struct ds2404_chip_ops *ops;
 	struct rtc_device *rtc;
 };

 static struct ds2404_gpio ds2404_gpio[] = {
 	{ "RTC RST", 0 },
 	{ "RTC CLK", 0 },
 	{ "RTC DQ", 0 },
 };

 static int ds2404_gpio_map(struct ds2404 *chip, struct platform_device *pdev,
 			  struct ds2404_platform_data *pdata)
 {
 	int i, err;

 	ds2404_gpio[DS2404_RST].gpio = pdata->gpio_rst;
 	ds2404_gpio[DS2404_CLK].gpio = pdata->gpio_clk;
 	ds2404_gpio[DS2404_DQ].gpio = pdata->gpio_dq;

 	for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) {
 		err = gpio_request(ds2404_gpio[i].gpio, ds2404_gpio[i].name);
 		if (err) {
 			dev_err(&pdev->dev, "error mapping gpio %s: %d\n",
 				ds2404_gpio[i].name, err);
 			goto err_request;
 		}
 		if (i != DS2404_DQ)
 			gpio_direction_output(ds2404_gpio[i].gpio, 1);
 	}

 	chip->gpio = ds2404_gpio;
 	return 0;

 err_request:
 	while (--i >= 0)
 		gpio_free(ds2404_gpio[i].gpio);
 	return err;
 }

 static void ds2404_gpio_unmap(struct ds2404 *chip)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++)
 		gpio_free(ds2404_gpio[i].gpio);
 }

 static struct ds2404_chip_ops ds2404_gpio_ops = {
 	.map_io		= ds2404_gpio_map,
 	.unmap_io	= ds2404_gpio_unmap,
 };

 static void ds2404_reset(struct device *dev)
 {
 	gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 0);
 	udelay(1000);
 	gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 1);
 	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
 	gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 0);
 	udelay(10);
 }

 static void ds2404_write_byte(struct device *dev, u8 byte)
 {
 	int i;

 	gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 1);
 	for (i = 0; i < 8; i++) {
 		gpio_set_value(ds2404_gpio[DS2404_DQ].gpio, byte & (1 << i));
 		udelay(10);
 		gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
 		udelay(10);
 		gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
 		udelay(10);
 	}
 }

 static u8 ds2404_read_byte(struct device *dev)
 {
 	int i;
 	u8 ret = 0;

 	gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);

 	for (i = 0; i < 8; i++) {
 		gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
 		udelay(10);
 		if (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
 			ret |= 1 << i;
 		gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
 		udelay(10);
 	}
 	return ret;
 }

 static void ds2404_read_memory(struct device *dev, u16 offset,
 			       int length, u8 *out)
 {
 	ds2404_reset(dev);
 	ds2404_write_byte(dev, DS2404_READ_MEMORY_CMD);
 	ds2404_write_byte(dev, offset & 0xff);
 	ds2404_write_byte(dev, (offset >> 8) & 0xff);
 	while (length--)
 		*out++ = ds2404_read_byte(dev);
 }

 static void ds2404_write_memory(struct device *dev, u16 offset,
 				int length, u8 *out)
 {
 	int i;
 	u8 ta01, ta02, es;

 	ds2404_reset(dev);
 	ds2404_write_byte(dev, DS2404_WRITE_SCRATCHPAD_CMD);
 	ds2404_write_byte(dev, offset & 0xff);
 	ds2404_write_byte(dev, (offset >> 8) & 0xff);

 	for (i = 0; i < length; i++)
 		ds2404_write_byte(dev, out[i]);

 	ds2404_reset(dev);
 	ds2404_write_byte(dev, DS2404_READ_SCRATCHPAD_CMD);

 	ta01 = ds2404_read_byte(dev);
 	ta02 = ds2404_read_byte(dev);
 	es = ds2404_read_byte(dev);

 	for (i = 0; i < length; i++) {
 		if (out[i] != ds2404_read_byte(dev)) {
 			dev_err(dev, "read invalid data\n");
 			return;
 		}
 	}

 	ds2404_reset(dev);
 	ds2404_write_byte(dev, DS2404_COPY_SCRATCHPAD_CMD);
 	ds2404_write_byte(dev, ta01);
 	ds2404_write_byte(dev, ta02);
 	ds2404_write_byte(dev, es);

 	gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);
 	while (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
 		;
 }

 static void ds2404_enable_osc(struct device *dev)
 {
 	u8 in[1] = { 0x10 }; /* enable oscillator */
 	ds2404_write_memory(dev, 0x201, 1, in);
 }

 static int ds2404_read_time(struct device *dev, struct rtc_time *dt)
 {
 	unsigned long time = 0;

 	ds2404_read_memory(dev, 0x203, 4, (u8 *)&time);
 	time = le32_to_cpu(time);

 	rtc_time_to_tm(time, dt);
 	return rtc_valid_tm(dt);
 }

 static int ds2404_set_mmss(struct device *dev, unsigned long secs)
 {
 	u32 time = cpu_to_le32(secs);
 	ds2404_write_memory(dev, 0x203, 4, (u8 *)&time);
 	return 0;
 }

 static const struct rtc_class_ops ds2404_rtc_ops = {
 	.read_time	= ds2404_read_time,
 	.set_mmss	= ds2404_set_mmss,
 };

 static int rtc_probe(struct platform_device *pdev)
 {
 	struct ds2404_platform_data *pdata = dev_get_platdata(&pdev->dev);
 	struct ds2404 *chip;
 	int retval = -EBUSY;

 	chip = devm_kzalloc(&pdev->dev, sizeof(struct ds2404), GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;

 	chip->ops = &ds2404_gpio_ops;

 	retval = chip->ops->map_io(chip, pdev, pdata);
 	if (retval)
 		goto err_chip;

 	dev_info(&pdev->dev, "using GPIOs RST:%d, CLK:%d, DQ:%d\n",
 		 chip->gpio[DS2404_RST].gpio, chip->gpio[DS2404_CLK].gpio,
 		 chip->gpio[DS2404_DQ].gpio);

 	platform_set_drvdata(pdev, chip);

 	chip->rtc = devm_rtc_device_register(&pdev->dev, "ds2404",
 					&ds2404_rtc_ops, THIS_MODULE);
 	if (IS_ERR(chip->rtc)) {
 		retval = PTR_ERR(chip->rtc);
 		goto err_io;
 	}

 	ds2404_enable_osc(&pdev->dev);
 	return 0;

 err_io:
 	chip->ops->unmap_io(chip);
 err_chip:
 	return retval;
 }

 static int rtc_remove(struct platform_device *dev)
 {
 	struct ds2404 *chip = platform_get_drvdata(dev);

 	chip->ops->unmap_io(chip);

 	return 0;
 }

 static struct platform_driver rtc_device_driver = {
 	.probe	= rtc_probe,
 	.remove = rtc_remove,
 	.driver = {
 		.name	= "ds2404",
 	},
 };
 module_platform_driver(rtc_device_driver);

 MODULE_DESCRIPTION("DS2404 RTC");
 MODULE_AUTHOR("Sven Schnelle");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:ds2404");
	/*
	* Copyright (C) 2012 Sven Schnelle <svens@stackframe.org>
	*
	* 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/platform_device.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/rtc.h>
	#include <linux/types.h>
	#include <linux/bcd.h>
	#include <linux/rtc-ds2404.h>
	#include <linux/delay.h>
	#include <linux/gpio.h>
	#include <linux/slab.h>

	#include <linux/io.h>

	#define DS2404_STATUS_REG 0x200
	#define DS2404_CONTROL_REG 0x201
	#define DS2404_RTC_REG 0x202

	#define DS2404_WRITE_SCRATCHPAD_CMD 0x0f
	#define DS2404_READ_SCRATCHPAD_CMD 0xaa
	#define DS2404_COPY_SCRATCHPAD_CMD 0x55
	#define DS2404_READ_MEMORY_CMD 0xf0

	struct ds2404;

	struct ds2404_chip_ops {
	int (map_io)(struct ds2404 chip, struct platform_device *pdev,
	struct ds2404_platform_data *pdata);
	void (unmap_io)(struct ds2404 chip);
	};

	#define DS2404_RST 0
	#define DS2404_CLK 1
	#define DS2404_DQ 2

	struct ds2404_gpio {
	const char *name;
	unsigned int gpio;
	};

	struct ds2404 {
	struct ds2404_gpio *gpio;
	struct ds2404_chip_ops *ops;
	struct rtc_device *rtc;
	};

	static struct ds2404_gpio ds2404_gpio[] = {
	{ "RTC RST", 0 },
	{ "RTC CLK", 0 },
	{ "RTC DQ", 0 },
	};

	static int ds2404_gpio_map(struct ds2404 chip, struct platform_device pdev,
	struct ds2404_platform_data *pdata)
	{
	int i, err;

	ds2404_gpio[DS2404_RST].gpio = pdata->gpio_rst;
	ds2404_gpio[DS2404_CLK].gpio = pdata->gpio_clk;
	ds2404_gpio[DS2404_DQ].gpio = pdata->gpio_dq;

	for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) {
	err = gpio_request(ds2404_gpio[i].gpio, ds2404_gpio[i].name);
	if (err) {
	dev_err(&pdev->dev, "error mapping gpio %s: %d\n",
	ds2404_gpio[i].name, err);
	goto err_request;
	}
	if (i != DS2404_DQ)
	gpio_direction_output(ds2404_gpio[i].gpio, 1);
	}

	chip->gpio = ds2404_gpio;
	return 0;

	err_request:
	while (--i >= 0)
	gpio_free(ds2404_gpio[i].gpio);
	return err;
	}

	static void ds2404_gpio_unmap(struct ds2404 *chip)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++)
	gpio_free(ds2404_gpio[i].gpio);
	}

	static struct ds2404_chip_ops ds2404_gpio_ops = {
	.map_io = ds2404_gpio_map,
	.unmap_io = ds2404_gpio_unmap,
	};

	static void ds2404_reset(struct device *dev)
	{
	gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 0);
	udelay(1000);
	gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 1);
	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
	gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 0);
	udelay(10);
	}

	static void ds2404_write_byte(struct device *dev, u8 byte)
	{
	int i;

	gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 1);
	for (i = 0; i < 8; i++) {
	gpio_set_value(ds2404_gpio[DS2404_DQ].gpio, byte & (1 << i));
	udelay(10);
	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
	udelay(10);
	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
	udelay(10);
	}
	}

	static u8 ds2404_read_byte(struct device *dev)
	{
	int i;
	u8 ret = 0;

	gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);

	for (i = 0; i < 8; i++) {
	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
	udelay(10);
	if (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
	ret \|= 1 << i;
	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
	udelay(10);
	}
	return ret;
	}

	static void ds2404_read_memory(struct device *dev, u16 offset,
	int length, u8 *out)
	{
	ds2404_reset(dev);
	ds2404_write_byte(dev, DS2404_READ_MEMORY_CMD);
	ds2404_write_byte(dev, offset & 0xff);
	ds2404_write_byte(dev, (offset >> 8) & 0xff);
	while (length--)
	*out++ = ds2404_read_byte(dev);
	}

	static void ds2404_write_memory(struct device *dev, u16 offset,
	int length, u8 *out)
	{
	int i;
	u8 ta01, ta02, es;

	ds2404_reset(dev);
	ds2404_write_byte(dev, DS2404_WRITE_SCRATCHPAD_CMD);
	ds2404_write_byte(dev, offset & 0xff);
	ds2404_write_byte(dev, (offset >> 8) & 0xff);

	for (i = 0; i < length; i++)
	ds2404_write_byte(dev, out[i]);

	ds2404_reset(dev);
	ds2404_write_byte(dev, DS2404_READ_SCRATCHPAD_CMD);

	ta01 = ds2404_read_byte(dev);
	ta02 = ds2404_read_byte(dev);
	es = ds2404_read_byte(dev);

	for (i = 0; i < length; i++) {
	if (out[i] != ds2404_read_byte(dev)) {
	dev_err(dev, "read invalid data\n");
	return;
	}
	}

	ds2404_reset(dev);
	ds2404_write_byte(dev, DS2404_COPY_SCRATCHPAD_CMD);
	ds2404_write_byte(dev, ta01);
	ds2404_write_byte(dev, ta02);
	ds2404_write_byte(dev, es);

	gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);
	while (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
	;
	}

	static void ds2404_enable_osc(struct device *dev)
	{
	u8 in[1] = { 0x10 }; /* enable oscillator */
	ds2404_write_memory(dev, 0x201, 1, in);
	}

	static int ds2404_read_time(struct device dev, struct rtc_time dt)
	{
	unsigned long time = 0;

	ds2404_read_memory(dev, 0x203, 4, (u8 *)&time);
	time = le32_to_cpu(time);

	rtc_time_to_tm(time, dt);
	return rtc_valid_tm(dt);
	}

	static int ds2404_set_mmss(struct device *dev, unsigned long secs)
	{
	u32 time = cpu_to_le32(secs);
	ds2404_write_memory(dev, 0x203, 4, (u8 *)&time);
	return 0;
	}

	static const struct rtc_class_ops ds2404_rtc_ops = {
	.read_time = ds2404_read_time,
	.set_mmss = ds2404_set_mmss,
	};

	static int rtc_probe(struct platform_device *pdev)
	{
	struct ds2404_platform_data *pdata = dev_get_platdata(&pdev->dev);
	struct ds2404 *chip;
	int retval = -EBUSY;

	chip = devm_kzalloc(&pdev->dev, sizeof(struct ds2404), GFP_KERNEL);
	if (!chip)
	return -ENOMEM;

	chip->ops = &ds2404_gpio_ops;

	retval = chip->ops->map_io(chip, pdev, pdata);
	if (retval)
	goto err_chip;

	dev_info(&pdev->dev, "using GPIOs RST:%d, CLK:%d, DQ:%d\n",
	chip->gpio[DS2404_RST].gpio, chip->gpio[DS2404_CLK].gpio,
	chip->gpio[DS2404_DQ].gpio);

	platform_set_drvdata(pdev, chip);

	chip->rtc = devm_rtc_device_register(&pdev->dev, "ds2404",
	&ds2404_rtc_ops, THIS_MODULE);
	if (IS_ERR(chip->rtc)) {
	retval = PTR_ERR(chip->rtc);
	goto err_io;
	}

	ds2404_enable_osc(&pdev->dev);
	return 0;

	err_io:
	chip->ops->unmap_io(chip);
	err_chip:
	return retval;
	}

	static int rtc_remove(struct platform_device *dev)
	{
	struct ds2404 *chip = platform_get_drvdata(dev);

	chip->ops->unmap_io(chip);

	return 0;
	}

	static struct platform_driver rtc_device_driver = {
	.probe = rtc_probe,
	.remove = rtc_remove,
	.driver = {
	.name = "ds2404",
	},
	};
	module_platform_driver(rtc_device_driver);

	MODULE_DESCRIPTION("DS2404 RTC");
	MODULE_AUTHOR("Sven Schnelle");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:ds2404");