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

/*
 * An rtc driver for the Dallas DS1742
 *
 * Copyright (C) 2006 Atsushi Nemoto <[email protected]>
 *
 * 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 <[email protected]>
 *  - 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;
	size_t size_nvram;
	unsigned long last_jiffies;
	struct bin_attribute nvram_attr;
};

static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	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 platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	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 rtc_valid_tm(tm);
}

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

static ssize_t ds1742_nvram_read(struct file *filp, struct kobject *kobj,
				 struct bin_attribute *bin_attr,
				 char *buf, loff_t pos, size_t size)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr_nvram;
	ssize_t count;

	for (count = 0; count < size; count++)
		*buf++ = readb(ioaddr + pos++);
	return count;
}

static ssize_t ds1742_nvram_write(struct file *filp, struct kobject *kobj,
				  struct bin_attribute *bin_attr,
				  char *buf, loff_t pos, size_t size)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr_nvram;
	ssize_t count;

	for (count = 0; count < size; count++)
		writeb(*buf++, ioaddr + pos++);
	return count;
}

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;

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

	sysfs_bin_attr_init(&pdata->nvram_attr);
	pdata->nvram_attr.attr.name = "nvram";
	pdata->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
	pdata->nvram_attr.read = ds1742_nvram_read;
	pdata->nvram_attr.write = ds1742_nvram_write;
	pdata->nvram_attr.size = pdata->size_nvram;

	/* 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_device_register(&pdev->dev, pdev->name,
				  &ds1742_rtc_ops, THIS_MODULE);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
	if (ret)
		dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n",
			pdata->nvram_attr.attr.name);

	return 0;
}

static int ds1742_rtc_remove(struct platform_device *pdev)
{
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
	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,
	.remove		= ds1742_rtc_remove,
	.driver		= {
		.name	= "rtc-ds1742",
		.of_match_table = of_match_ptr(ds1742_rtc_of_match),
	},
};

module_platform_driver(ds1742_rtc_driver);

MODULE_AUTHOR("Atsushi Nemoto <[email protected]>");
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 <[email protected]>
	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 <[email protected]>
	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;
	55	void __iomem *ioaddr_rtc;
	56	size_t size_nvram;
5ec3e4b7	57	unsigned long last_jiffies;
3a729700	58	struct bin_attribute nvram_attr;
5ec3e4b7 AN	59	};
	60
	61	static int ds1742_rtc_set_time(struct device dev, struct rtc_time tm)
	62	{
	63	struct platform_device *pdev = to_platform_device(dev);
	64	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
f9231a0c	65	void __iomem *ioaddr = pdata->ioaddr_rtc;
5ec3e4b7 AN	66	u8 century;
5ec3e4b7 AN	67
fe20ba70	68	century = bin2bcd((tm->tm_year + 1900) / 100);
5ec3e4b7 AN	69
	70	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
	71
fe20ba70 AB	72	writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
	73	writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
	74	writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
	75	writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
	76	writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
	77	writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
	78	writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
5ec3e4b7 AN	79
	80	/* RTC_CENTURY and RTC_CONTROL share same register */
	81	writeb(RTC_WRITE \| (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
	82	writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
	83	return 0;
	84	}
	85
	86	static int ds1742_rtc_read_time(struct device dev, struct rtc_time tm)
	87	{
	88	struct platform_device *pdev = to_platform_device(dev);
	89	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
f9231a0c	90	void __iomem *ioaddr = pdata->ioaddr_rtc;
5ec3e4b7 AN	91	unsigned int year, month, day, hour, minute, second, week;
	92	unsigned int century;
	93
	94	/* give enough time to update RTC in case of continuous read */
	95	if (pdata->last_jiffies == jiffies)
	96	msleep(1);
	97	pdata->last_jiffies = jiffies;
	98	writeb(RTC_READ, ioaddr + RTC_CONTROL);
	99	second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
	100	minute = readb(ioaddr + RTC_MINUTES);
	101	hour = readb(ioaddr + RTC_HOURS);
	102	day = readb(ioaddr + RTC_DATE);
	103	week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
	104	month = readb(ioaddr + RTC_MONTH);
	105	year = readb(ioaddr + RTC_YEAR);
	106	century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
	107	writeb(0, ioaddr + RTC_CONTROL);
fe20ba70 AB	108	tm->tm_sec = bcd2bin(second);
	109	tm->tm_min = bcd2bin(minute);
	110	tm->tm_hour = bcd2bin(hour);
	111	tm->tm_mday = bcd2bin(day);
	112	tm->tm_wday = bcd2bin(week);
	113	tm->tm_mon = bcd2bin(month) - 1;
5ec3e4b7	114	/* year is 1900 + tm->tm_year */
fe20ba70	115	tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
5ec3e4b7	116
1735be4b	117	return rtc_valid_tm(tm);
5ec3e4b7 AN	118	}
5ec3e4b7 AN	119
ff8371ac	120	static const struct rtc_class_ops ds1742_rtc_ops = {
5ec3e4b7 AN	121	.read_time = ds1742_rtc_read_time,
	122	.set_time = ds1742_rtc_set_time,
	123	};
	124
2c3c8bea	125	static ssize_t ds1742_nvram_read(struct file filp, struct kobject kobj,
91a69029 ZR	126	struct bin_attribute *bin_attr,
91a69029 ZR	127	char *buf, loff_t pos, size_t size)
5ec3e4b7	128	{
50e49bee AN	129	struct device *dev = container_of(kobj, struct device, kobj);
50e49bee AN	130	struct platform_device *pdev = to_platform_device(dev);
5ec3e4b7	131	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
f9231a0c	132	void __iomem *ioaddr = pdata->ioaddr_nvram;
5ec3e4b7 AN	133	ssize_t count;
5ec3e4b7 AN	134
c472d7de	135	for (count = 0; count < size; count++)
5ec3e4b7 AN	136	*buf++ = readb(ioaddr + pos++);
	137	return count;
	138	}
	139
2c3c8bea	140	static ssize_t ds1742_nvram_write(struct file filp, struct kobject kobj,
91a69029 ZR	141	struct bin_attribute *bin_attr,
91a69029 ZR	142	char *buf, loff_t pos, size_t size)
5ec3e4b7	143	{
50e49bee AN	144	struct device *dev = container_of(kobj, struct device, kobj);
50e49bee AN	145	struct platform_device *pdev = to_platform_device(dev);
5ec3e4b7	146	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
f9231a0c	147	void __iomem *ioaddr = pdata->ioaddr_nvram;
5ec3e4b7 AN	148	ssize_t count;
5ec3e4b7 AN	149
c472d7de	150	for (count = 0; count < size; count++)
5ec3e4b7 AN	151	writeb(*buf++, ioaddr + pos++);
	152	return count;
	153	}
	154
5a167f45	155	static int ds1742_rtc_probe(struct platform_device *pdev)
5ec3e4b7 AN	156	{
	157	struct rtc_device *rtc;
	158	struct resource *res;
	159	unsigned int cen, sec;
ac18eb62 AN	160	struct rtc_plat_data *pdata;
ac18eb62 AN	161	void __iomem *ioaddr;
5ec3e4b7 AN	162	int ret = 0;
5ec3e4b7 AN	163
ac18eb62	164	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
5ec3e4b7 AN	165	if (!pdata)
5ec3e4b7 AN	166	return -ENOMEM;
25e2818e AS	167
	168	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	169	ioaddr = devm_ioremap_resource(&pdev->dev, res);
	170	if (IS_ERR(ioaddr))
	171	return PTR_ERR(ioaddr);
ac18eb62	172
f9231a0c	173	pdata->ioaddr_nvram = ioaddr;
25e2818e	174	pdata->size_nvram = resource_size(res) - RTC_SIZE;
f9231a0c	175	pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
5ec3e4b7	176
f937331b	177	sysfs_bin_attr_init(&pdata->nvram_attr);
3a729700 TER	178	pdata->nvram_attr.attr.name = "nvram";
	179	pdata->nvram_attr.attr.mode = S_IRUGO \| S_IWUSR;
	180	pdata->nvram_attr.read = ds1742_nvram_read;
	181	pdata->nvram_attr.write = ds1742_nvram_write;
	182	pdata->nvram_attr.size = pdata->size_nvram;
	183
5ec3e4b7	184	/* turn RTC on if it was not on */
f9231a0c	185	ioaddr = pdata->ioaddr_rtc;
5ec3e4b7 AN	186	sec = readb(ioaddr + RTC_SECONDS);
	187	if (sec & RTC_STOP) {
	188	sec &= RTC_SECONDS_MASK;
	189	cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
	190	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
	191	writeb(sec, ioaddr + RTC_SECONDS);
	192	writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
	193	}
391b1fe6	194	if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
5ec3e4b7 AN	195	dev_warn(&pdev->dev, "voltage-low detected.\n");
5ec3e4b7 AN	196
ac18eb62 AN	197	pdata->last_jiffies = jiffies;
ac18eb62 AN	198	platform_set_drvdata(pdev, pdata);
f7cfdea0	199	rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
5ec3e4b7	200	&ds1742_rtc_ops, THIS_MODULE);
ac18eb62 AN	201	if (IS_ERR(rtc))
ac18eb62 AN	202	return PTR_ERR(rtc);
3a729700 TER	203
3a729700 TER	204	ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
4071ea25 AZ	205	if (ret)
	206	dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n",
	207	pdata->nvram_attr.attr.name);
f7cfdea0	208
4071ea25	209	return 0;
5ec3e4b7 AN	210	}
5ec3e4b7 AN	211
5a167f45	212	static int ds1742_rtc_remove(struct platform_device *pdev)
5ec3e4b7 AN	213	{
	214	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	215
3a729700	216	sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
5ec3e4b7 AN	217	return 0;
	218	}
	219
9d203572	220	static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
663b3524 AS	221	{ .compatible = "maxim,ds1742", },
	222	{ }
	223	};
	224	MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
	225
5ec3e4b7 AN	226	static struct platform_driver ds1742_rtc_driver = {
5ec3e4b7 AN	227	.probe = ds1742_rtc_probe,
5a167f45	228	.remove = ds1742_rtc_remove,
5ec3e4b7	229	.driver = {
a95e23a2	230	.name = "rtc-ds1742",
3710f597	231	.of_match_table = of_match_ptr(ds1742_rtc_of_match),
5ec3e4b7 AN	232	},
	233	};
	234
0c4eae66	235	module_platform_driver(ds1742_rtc_driver);
5ec3e4b7 AN	236
	237	MODULE_AUTHOR("Atsushi Nemoto <[email protected]>");
	238	MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
	239	MODULE_LICENSE("GPL");
ad28a07b	240	MODULE_ALIAS("platform:rtc-ds1742");