[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / rtc / rtc-ds2404.c

/*
 * 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 = pdev->dev.platform_data;
	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",
		.owner	= THIS_MODULE,
	},
};
module_platform_driver(rtc_device_driver);

MODULE_DESCRIPTION("DS2404 RTC");
MODULE_AUTHOR("Sven Schnelle");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ds2404");
Commit	Line	Data
7418a119 SS	1	/*
	2	* Copyright (C) 2012 Sven Schnelle <svens@stackframe.org>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	*/
	9
	10	#include <linux/platform_device.h>
	11	#include <linux/module.h>
	12	#include <linux/init.h>
	13	#include <linux/rtc.h>
	14	#include <linux/types.h>
	15	#include <linux/bcd.h>
	16	#include <linux/rtc-ds2404.h>
	17	#include <linux/delay.h>
	18	#include <linux/gpio.h>
	19	#include <linux/slab.h>
	20
	21	#include <linux/io.h>
	22
	23	#define DS2404_STATUS_REG 0x200
	24	#define DS2404_CONTROL_REG 0x201
	25	#define DS2404_RTC_REG 0x202
	26
	27	#define DS2404_WRITE_SCRATCHPAD_CMD 0x0f
	28	#define DS2404_READ_SCRATCHPAD_CMD 0xaa
	29	#define DS2404_COPY_SCRATCHPAD_CMD 0x55
	30	#define DS2404_READ_MEMORY_CMD 0xf0
	31
	32	struct ds2404;
	33
	34	struct ds2404_chip_ops {
	35	int (map_io)(struct ds2404 chip, struct platform_device *pdev,
	36	struct ds2404_platform_data *pdata);
	37	void (unmap_io)(struct ds2404 chip);
	38	};
	39
	40	#define DS2404_RST 0
	41	#define DS2404_CLK 1
	42	#define DS2404_DQ 2
	43
	44	struct ds2404_gpio {
	45	const char *name;
	46	unsigned int gpio;
	47	};
	48
	49	struct ds2404 {
	50	struct ds2404_gpio *gpio;
	51	struct ds2404_chip_ops *ops;
	52	struct rtc_device *rtc;
	53	};
	54
	55	static struct ds2404_gpio ds2404_gpio[] = {
	56	{ "RTC RST", 0 },
	57	{ "RTC CLK", 0 },
	58	{ "RTC DQ", 0 },
	59	};
	60
	61	static int ds2404_gpio_map(struct ds2404 chip, struct platform_device pdev,
	62	struct ds2404_platform_data *pdata)
	63	{
	64	int i, err;
65
66	ds2404_gpio[DS2404_RST].gpio = pdata->gpio_rst;
67	ds2404_gpio[DS2404_CLK].gpio = pdata->gpio_clk;
68	ds2404_gpio[DS2404_DQ].gpio = pdata->gpio_dq;
69
70	for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) {
71	err = gpio_request(ds2404_gpio[i].gpio, ds2404_gpio[i].name);
72	if (err) {
0fae8237	73	dev_err(&pdev->dev, "error mapping gpio %s: %d\n",
7418a119 SS	74	ds2404_gpio[i].name, err);
	75	goto err_request;
	76	}
	77	if (i != DS2404_DQ)
	78	gpio_direction_output(ds2404_gpio[i].gpio, 1);
	79	}
	80
	81	chip->gpio = ds2404_gpio;
	82	return 0;
	83
	84	err_request:
	85	while (--i >= 0)
	86	gpio_free(ds2404_gpio[i].gpio);
	87	return err;
	88	}
	89
	90	static void ds2404_gpio_unmap(struct ds2404 *chip)
	91	{
	92	int i;
	93
	94	for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++)
	95	gpio_free(ds2404_gpio[i].gpio);
	96	}
	97
	98	static struct ds2404_chip_ops ds2404_gpio_ops = {
	99	.map_io = ds2404_gpio_map,
	100	.unmap_io = ds2404_gpio_unmap,
	101	};
	102
	103	static void ds2404_reset(struct device *dev)
	104	{
	105	gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 0);
	106	udelay(1000);
	107	gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 1);
	108	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
	109	gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 0);
	110	udelay(10);
	111	}
	112
	113	static void ds2404_write_byte(struct device *dev, u8 byte)
	114	{
	115	int i;
	116
	117	gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 1);
	118	for (i = 0; i < 8; i++) {
	119	gpio_set_value(ds2404_gpio[DS2404_DQ].gpio, byte & (1 << i));
	120	udelay(10);
	121	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
	122	udelay(10);
	123	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
	124	udelay(10);
	125	}
	126	}
	127
	128	static u8 ds2404_read_byte(struct device *dev)
	129	{
	130	int i;
	131	u8 ret = 0;
	132
	133	gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);
	134
	135	for (i = 0; i < 8; i++) {
	136	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0);
	137	udelay(10);
138	if (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
139	ret \|= 1 << i;
140	gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1);
141	udelay(10);
142	}
143	return ret;
144	}
145
146	static void ds2404_read_memory(struct device *dev, u16 offset,
147	int length, u8 *out)
148	{
149	ds2404_reset(dev);
150	ds2404_write_byte(dev, DS2404_READ_MEMORY_CMD);
151	ds2404_write_byte(dev, offset & 0xff);
152	ds2404_write_byte(dev, (offset >> 8) & 0xff);
153	while (length--)
154	*out++ = ds2404_read_byte(dev);
155	}
156
157	static void ds2404_write_memory(struct device *dev, u16 offset,
158	int length, u8 *out)
159	{
160	int i;
161	u8 ta01, ta02, es;
162
163	ds2404_reset(dev);
164	ds2404_write_byte(dev, DS2404_WRITE_SCRATCHPAD_CMD);
165	ds2404_write_byte(dev, offset & 0xff);
166	ds2404_write_byte(dev, (offset >> 8) & 0xff);
167
168	for (i = 0; i < length; i++)
169	ds2404_write_byte(dev, out[i]);
170
171	ds2404_reset(dev);
172	ds2404_write_byte(dev, DS2404_READ_SCRATCHPAD_CMD);
173
174	ta01 = ds2404_read_byte(dev);
175	ta02 = ds2404_read_byte(dev);
176	es = ds2404_read_byte(dev);
177
178	for (i = 0; i < length; i++) {
179	if (out[i] != ds2404_read_byte(dev)) {
0fae8237	180	dev_err(dev, "read invalid data\n");
7418a119 SS	181	return;
	182	}
	183	}
	184
	185	ds2404_reset(dev);
	186	ds2404_write_byte(dev, DS2404_COPY_SCRATCHPAD_CMD);
	187	ds2404_write_byte(dev, ta01);
	188	ds2404_write_byte(dev, ta02);
	189	ds2404_write_byte(dev, es);
	190
	191	gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio);
	192	while (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio))
	193	;
	194	}
	195
	196	static void ds2404_enable_osc(struct device *dev)
	197	{
	198	u8 in[1] = { 0x10 }; /* enable oscillator */
	199	ds2404_write_memory(dev, 0x201, 1, in);
	200	}
	201
	202	static int ds2404_read_time(struct device dev, struct rtc_time dt)
	203	{
	204	unsigned long time = 0;
	205
	206	ds2404_read_memory(dev, 0x203, 4, (u8 *)&time);
	207	time = le32_to_cpu(time);
	208
	209	rtc_time_to_tm(time, dt);
	210	return rtc_valid_tm(dt);
	211	}
	212
	213	static int ds2404_set_mmss(struct device *dev, unsigned long secs)
	214	{
	215	u32 time = cpu_to_le32(secs);
	216	ds2404_write_memory(dev, 0x203, 4, (u8 *)&time);
	217	return 0;
	218	}
	219
	220	static const struct rtc_class_ops ds2404_rtc_ops = {
	221	.read_time = ds2404_read_time,
	222	.set_mmss = ds2404_set_mmss,
	223	};
	224
	225	static int rtc_probe(struct platform_device *pdev)
	226	{
	227	struct ds2404_platform_data *pdata = pdev->dev.platform_data;
	228	struct ds2404 *chip;
	229	int retval = -EBUSY;
	230
2a444cf7	231	chip = devm_kzalloc(&pdev->dev, sizeof(struct ds2404), GFP_KERNEL);
7418a119 SS	232	if (!chip)
	233	return -ENOMEM;
	234
	235	chip->ops = &ds2404_gpio_ops;
	236
	237	retval = chip->ops->map_io(chip, pdev, pdata);
	238	if (retval)
	239	goto err_chip;
	240
	241	dev_info(&pdev->dev, "using GPIOs RST:%d, CLK:%d, DQ:%d\n",
	242	chip->gpio[DS2404_RST].gpio, chip->gpio[DS2404_CLK].gpio,
	243	chip->gpio[DS2404_DQ].gpio);
	244
	245	platform_set_drvdata(pdev, chip);
	246
2a444cf7 JH	247	chip->rtc = devm_rtc_device_register(&pdev->dev, "ds2404",
2a444cf7 JH	248	&ds2404_rtc_ops, THIS_MODULE);
7418a119 SS	249	if (IS_ERR(chip->rtc)) {
	250	retval = PTR_ERR(chip->rtc);
	251	goto err_io;
	252	}
	253
	254	ds2404_enable_osc(&pdev->dev);
	255	return 0;
	256
	257	err_io:
	258	chip->ops->unmap_io(chip);
	259	err_chip:
7418a119 SS	260	return retval;
	261	}
	262
	263	static int rtc_remove(struct platform_device *dev)
	264	{
	265	struct ds2404 *chip = platform_get_drvdata(dev);
7418a119 SS	266
7418a119 SS	267	chip->ops->unmap_io(chip);
7418a119 SS	268
	269	return 0;
	270	}
	271
	272	static struct platform_driver rtc_device_driver = {
	273	.probe = rtc_probe,
	274	.remove = rtc_remove,
	275	.driver = {
	276	.name = "ds2404",
	277	.owner = THIS_MODULE,
	278	},
	279	};
56ae1b8e	280	module_platform_driver(rtc_device_driver);
7418a119 SS	281
	282	MODULE_DESCRIPTION("DS2404 RTC");
	283	MODULE_AUTHOR("Sven Schnelle");
	284	MODULE_LICENSE("GPL");
	285	MODULE_ALIAS("platform:ds2404");