[linux-2.6-block.git] / drivers / rtc / rtc-ds1742.c

/*
 * An rtc driver for the Dallas DS1742
 *
 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
 *
 * 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.
 *
 * Copyright (C) 2006 Torsten Ertbjerg Rasmussen <tr@newtec.dk>
 *  - nvram size determined from resource
 *  - this ds1742 driver now supports ds1743.
 */

#include <linux/bcd.h>
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/rtc.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/module.h>

#define RTC_SIZE		8

#define RTC_CONTROL		0
#define RTC_CENTURY		0
#define RTC_SECONDS		1
#define RTC_MINUTES		2
#define RTC_HOURS		3
#define RTC_DAY			4
#define RTC_DATE		5
#define RTC_MONTH		6
#define RTC_YEAR		7

#define RTC_CENTURY_MASK	0x3f
#define RTC_SECONDS_MASK	0x7f
#define RTC_DAY_MASK		0x07

/* Bits in the Control/Century register */
#define RTC_WRITE		0x80
#define RTC_READ		0x40

/* Bits in the Seconds register */
#define RTC_STOP		0x80

/* Bits in the Day register */
#define RTC_BATT_FLAG		0x80

struct rtc_plat_data {
	void __iomem *ioaddr_nvram;
	void __iomem *ioaddr_rtc;
	unsigned long last_jiffies;
};

static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
	void __iomem *ioaddr = pdata->ioaddr_rtc;
	u8 century;

	century = bin2bcd((tm->tm_year + 1900) / 100);

	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);

	writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
	writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
	writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
	writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
	writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
	writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
	writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);

	/* RTC_CENTURY and RTC_CONTROL share same register */
	writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
	writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
	return 0;
}

static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
	void __iomem *ioaddr = pdata->ioaddr_rtc;
	unsigned int year, month, day, hour, minute, second, week;
	unsigned int century;

	/* give enough time to update RTC in case of continuous read */
	if (pdata->last_jiffies == jiffies)
		msleep(1);
	pdata->last_jiffies = jiffies;
	writeb(RTC_READ, ioaddr + RTC_CONTROL);
	second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
	minute = readb(ioaddr + RTC_MINUTES);
	hour = readb(ioaddr + RTC_HOURS);
	day = readb(ioaddr + RTC_DATE);
	week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
	month = readb(ioaddr + RTC_MONTH);
	year = readb(ioaddr + RTC_YEAR);
	century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
	writeb(0, ioaddr + RTC_CONTROL);
	tm->tm_sec = bcd2bin(second);
	tm->tm_min = bcd2bin(minute);
	tm->tm_hour = bcd2bin(hour);
	tm->tm_mday = bcd2bin(day);
	tm->tm_wday = bcd2bin(week);
	tm->tm_mon = bcd2bin(month) - 1;
	/* year is 1900 + tm->tm_year */
	tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;

	return 0;
}

static const struct rtc_class_ops ds1742_rtc_ops = {
	.read_time	= ds1742_rtc_read_time,
	.set_time	= ds1742_rtc_set_time,
};

static int ds1742_nvram_read(void *priv, unsigned int pos, void *val,
			     size_t bytes)
{
	struct rtc_plat_data *pdata = priv;
	void __iomem *ioaddr = pdata->ioaddr_nvram;
	u8 *buf = val;

	for (; bytes; bytes--)
		*buf++ = readb(ioaddr + pos++);
	return 0;
}

static int ds1742_nvram_write(void *priv, unsigned int pos, void *val,
			      size_t bytes)
{
	struct rtc_plat_data *pdata = priv;
	void __iomem *ioaddr = pdata->ioaddr_nvram;
	u8 *buf = val;

	for (; bytes; bytes--)
		writeb(*buf++, ioaddr + pos++);
	return 0;
}

static int ds1742_rtc_probe(struct platform_device *pdev)
{
	struct rtc_device *rtc;
	struct resource *res;
	unsigned int cen, sec;
	struct rtc_plat_data *pdata;
	void __iomem *ioaddr;
	int ret = 0;
	struct nvmem_config nvmem_cfg = {
		.name = "ds1742_nvram",
		.reg_read = ds1742_nvram_read,
		.reg_write = ds1742_nvram_write,
	};


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

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	ioaddr = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(ioaddr))
		return PTR_ERR(ioaddr);

	pdata->ioaddr_nvram = ioaddr;
	pdata->ioaddr_rtc = ioaddr + resource_size(res) - RTC_SIZE;

	nvmem_cfg.size = resource_size(res) - RTC_SIZE;
	nvmem_cfg.priv = pdata;

	/* turn RTC on if it was not on */
	ioaddr = pdata->ioaddr_rtc;
	sec = readb(ioaddr + RTC_SECONDS);
	if (sec & RTC_STOP) {
		sec &= RTC_SECONDS_MASK;
		cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
		writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
		writeb(sec, ioaddr + RTC_SECONDS);
		writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
	}
	if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
		dev_warn(&pdev->dev, "voltage-low detected.\n");

	pdata->last_jiffies = jiffies;
	platform_set_drvdata(pdev, pdata);

	rtc = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	rtc->ops = &ds1742_rtc_ops;
	rtc->nvram_old_abi = true;

	ret = rtc_register_device(rtc);
	if (ret)
		return ret;

	if (rtc_nvmem_register(rtc, &nvmem_cfg))
		dev_err(&pdev->dev, "Unable to register nvmem\n");

	return 0;
}

static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
	{ .compatible = "maxim,ds1742", },
	{ }
};
MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);

static struct platform_driver ds1742_rtc_driver = {
	.probe		= ds1742_rtc_probe,
	.driver		= {
		.name	= "rtc-ds1742",
		.of_match_table = of_match_ptr(ds1742_rtc_of_match),
	},
};

module_platform_driver(ds1742_rtc_driver);

MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:rtc-ds1742");
Commit	Line	Data
5ec3e4b7 AN	1	/*
	2	* An rtc driver for the Dallas DS1742
	3	*
	4	* Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
f9231a0c TER	9	*
	10	* Copyright (C) 2006 Torsten Ertbjerg Rasmussen <tr@newtec.dk>
	11	* - nvram size determined from resource
	12	* - this ds1742 driver now supports ds1743.
5ec3e4b7 AN	13	*/
	14
	15	#include <linux/bcd.h>
5ec3e4b7	16	#include <linux/kernel.h>
5a0e3ad6	17	#include <linux/gfp.h>
5ec3e4b7 AN	18	#include <linux/delay.h>
	19	#include <linux/jiffies.h>
	20	#include <linux/rtc.h>
663b3524 AS	21	#include <linux/of.h>
663b3524 AS	22	#include <linux/of_device.h>
5ec3e4b7 AN	23	#include <linux/platform_device.h>
5ec3e4b7 AN	24	#include <linux/io.h>
2113852b	25	#include <linux/module.h>
5ec3e4b7	26
f9231a0c	27	#define RTC_SIZE 8
5ec3e4b7	28
f9231a0c TER	29	#define RTC_CONTROL 0
	30	#define RTC_CENTURY 0
	31	#define RTC_SECONDS 1
	32	#define RTC_MINUTES 2
	33	#define RTC_HOURS 3
	34	#define RTC_DAY 4
	35	#define RTC_DATE 5
	36	#define RTC_MONTH 6
	37	#define RTC_YEAR 7
5ec3e4b7 AN	38
	39	#define RTC_CENTURY_MASK 0x3f
	40	#define RTC_SECONDS_MASK 0x7f
	41	#define RTC_DAY_MASK 0x07
	42
	43	/* Bits in the Control/Century register */
	44	#define RTC_WRITE 0x80
	45	#define RTC_READ 0x40
	46
	47	/* Bits in the Seconds register */
	48	#define RTC_STOP 0x80
	49
	50	/* Bits in the Day register */
	51	#define RTC_BATT_FLAG 0x80
	52
	53	struct rtc_plat_data {
f9231a0c TER	54	void __iomem *ioaddr_nvram;
f9231a0c TER	55	void __iomem *ioaddr_rtc;
5ec3e4b7 AN	56	unsigned long last_jiffies;
	57	};
	58
	59	static int ds1742_rtc_set_time(struct device dev, struct rtc_time tm)
	60	{
85368bb9	61	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
f9231a0c	62	void __iomem *ioaddr = pdata->ioaddr_rtc;
5ec3e4b7 AN	63	u8 century;
5ec3e4b7 AN	64
fe20ba70	65	century = bin2bcd((tm->tm_year + 1900) / 100);
5ec3e4b7 AN	66
	67	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
	68
fe20ba70 AB	69	writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
	70	writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
	71	writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
	72	writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
	73	writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
	74	writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
	75	writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
5ec3e4b7 AN	76
	77	/* RTC_CENTURY and RTC_CONTROL share same register */
	78	writeb(RTC_WRITE \| (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
	79	writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
	80	return 0;
	81	}
	82
	83	static int ds1742_rtc_read_time(struct device dev, struct rtc_time tm)
	84	{
85368bb9	85	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
f9231a0c	86	void __iomem *ioaddr = pdata->ioaddr_rtc;
5ec3e4b7 AN	87	unsigned int year, month, day, hour, minute, second, week;
	88	unsigned int century;
	89
	90	/* give enough time to update RTC in case of continuous read */
	91	if (pdata->last_jiffies == jiffies)
	92	msleep(1);
	93	pdata->last_jiffies = jiffies;
	94	writeb(RTC_READ, ioaddr + RTC_CONTROL);
	95	second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
	96	minute = readb(ioaddr + RTC_MINUTES);
	97	hour = readb(ioaddr + RTC_HOURS);
	98	day = readb(ioaddr + RTC_DATE);
	99	week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
	100	month = readb(ioaddr + RTC_MONTH);
	101	year = readb(ioaddr + RTC_YEAR);
	102	century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
	103	writeb(0, ioaddr + RTC_CONTROL);
fe20ba70 AB	104	tm->tm_sec = bcd2bin(second);
	105	tm->tm_min = bcd2bin(minute);
	106	tm->tm_hour = bcd2bin(hour);
	107	tm->tm_mday = bcd2bin(day);
	108	tm->tm_wday = bcd2bin(week);
	109	tm->tm_mon = bcd2bin(month) - 1;
5ec3e4b7	110	/* year is 1900 + tm->tm_year */
fe20ba70	111	tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
5ec3e4b7	112
22652ba7	113	return 0;
5ec3e4b7 AN	114	}
5ec3e4b7 AN	115
ff8371ac	116	static const struct rtc_class_ops ds1742_rtc_ops = {
5ec3e4b7 AN	117	.read_time = ds1742_rtc_read_time,
	118	.set_time = ds1742_rtc_set_time,
	119	};
	120
87c78d95 AB	121	static int ds1742_nvram_read(void priv, unsigned int pos, void val,
87c78d95 AB	122	size_t bytes)
5ec3e4b7	123	{
87c78d95	124	struct rtc_plat_data *pdata = priv;
f9231a0c	125	void __iomem *ioaddr = pdata->ioaddr_nvram;
87c78d95	126	u8 *buf = val;
5ec3e4b7	127
87c78d95	128	for (; bytes; bytes--)
5ec3e4b7	129	*buf++ = readb(ioaddr + pos++);
87c78d95	130	return 0;
5ec3e4b7 AN	131	}
5ec3e4b7 AN	132
87c78d95 AB	133	static int ds1742_nvram_write(void priv, unsigned int pos, void val,
87c78d95 AB	134	size_t bytes)
5ec3e4b7	135	{
87c78d95	136	struct rtc_plat_data *pdata = priv;
f9231a0c	137	void __iomem *ioaddr = pdata->ioaddr_nvram;
87c78d95	138	u8 *buf = val;
5ec3e4b7	139
87c78d95	140	for (; bytes; bytes--)
5ec3e4b7	141	writeb(*buf++, ioaddr + pos++);
87c78d95	142	return 0;
5ec3e4b7 AN	143	}
5ec3e4b7 AN	144
5a167f45	145	static int ds1742_rtc_probe(struct platform_device *pdev)
5ec3e4b7 AN	146	{
	147	struct rtc_device *rtc;
	148	struct resource *res;
	149	unsigned int cen, sec;
ac18eb62 AN	150	struct rtc_plat_data *pdata;
ac18eb62 AN	151	void __iomem *ioaddr;
5ec3e4b7	152	int ret = 0;
87c78d95 AB	153	struct nvmem_config nvmem_cfg = {
87c78d95 AB	154	.name = "ds1742_nvram",
87c78d95 AB	155	.reg_read = ds1742_nvram_read,
	156	.reg_write = ds1742_nvram_write,
	157	};
	158
5ec3e4b7	159
ac18eb62	160	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
5ec3e4b7 AN	161	if (!pdata)
5ec3e4b7 AN	162	return -ENOMEM;
25e2818e AS	163
	164	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	165	ioaddr = devm_ioremap_resource(&pdev->dev, res);
	166	if (IS_ERR(ioaddr))
	167	return PTR_ERR(ioaddr);
ac18eb62	168
f9231a0c	169	pdata->ioaddr_nvram = ioaddr;
87c78d95	170	pdata->ioaddr_rtc = ioaddr + resource_size(res) - RTC_SIZE;
5ec3e4b7	171
87c78d95 AB	172	nvmem_cfg.size = resource_size(res) - RTC_SIZE;
87c78d95 AB	173	nvmem_cfg.priv = pdata;
3a729700	174
5ec3e4b7	175	/* turn RTC on if it was not on */
f9231a0c	176	ioaddr = pdata->ioaddr_rtc;
5ec3e4b7 AN	177	sec = readb(ioaddr + RTC_SECONDS);
	178	if (sec & RTC_STOP) {
	179	sec &= RTC_SECONDS_MASK;
	180	cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
	181	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
	182	writeb(sec, ioaddr + RTC_SECONDS);
	183	writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
	184	}
391b1fe6	185	if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
5ec3e4b7 AN	186	dev_warn(&pdev->dev, "voltage-low detected.\n");
5ec3e4b7 AN	187
ac18eb62 AN	188	pdata->last_jiffies = jiffies;
ac18eb62 AN	189	platform_set_drvdata(pdev, pdata);
1358e7b2 AB	190
1358e7b2 AB	191	rtc = devm_rtc_allocate_device(&pdev->dev);
ac18eb62 AN	192	if (IS_ERR(rtc))
ac18eb62 AN	193	return PTR_ERR(rtc);
3a729700	194
1358e7b2	195	rtc->ops = &ds1742_rtc_ops;
87c78d95	196	rtc->nvram_old_abi = true;
1358e7b2 AB	197
	198	ret = rtc_register_device(rtc);
	199	if (ret)
	200	return ret;
	201
87c78d95 AB	202	if (rtc_nvmem_register(rtc, &nvmem_cfg))
87c78d95 AB	203	dev_err(&pdev->dev, "Unable to register nvmem\n");
5ec3e4b7	204
5ec3e4b7 AN	205	return 0;
	206	}
	207
9d203572	208	static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
663b3524 AS	209	{ .compatible = "maxim,ds1742", },
	210	{ }
	211	};
	212	MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
	213
5ec3e4b7 AN	214	static struct platform_driver ds1742_rtc_driver = {
5ec3e4b7 AN	215	.probe = ds1742_rtc_probe,
5ec3e4b7	216	.driver = {
a95e23a2	217	.name = "rtc-ds1742",
3710f597	218	.of_match_table = of_match_ptr(ds1742_rtc_of_match),
5ec3e4b7 AN	219	},
	220	};
	221
0c4eae66	222	module_platform_driver(ds1742_rtc_driver);
5ec3e4b7 AN	223
	224	MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
	225	MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
	226	MODULE_LICENSE("GPL");
ad28a07b	227	MODULE_ALIAS("platform:rtc-ds1742");