[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.
 */

#include <linux/bcd.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>

#define DRV_VERSION "0.1"

#define RTC_REG_SIZE		0x800
#define RTC_OFFSET		0x7f8

#define RTC_CONTROL		(RTC_OFFSET + 0)
#define RTC_CENTURY		(RTC_OFFSET + 0)
#define RTC_SECONDS		(RTC_OFFSET + 1)
#define RTC_MINUTES		(RTC_OFFSET + 2)
#define RTC_HOURS		(RTC_OFFSET + 3)
#define RTC_DAY			(RTC_OFFSET + 4)
#define RTC_DATE		(RTC_OFFSET + 5)
#define RTC_MONTH		(RTC_OFFSET + 6)
#define RTC_YEAR		(RTC_OFFSET + 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 {
	struct rtc_device *rtc;
	void __iomem *ioaddr;
	unsigned long baseaddr;
	unsigned long last_jiffies;
};

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;
	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;
	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;

	if (rtc_valid_tm(tm) < 0) {
		dev_err(dev, "retrieved date/time is not valid.\n");
		rtc_time_to_tm(0, tm);
	}
	return 0;
}

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

	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
		*buf++ = readb(ioaddr + pos++);
	return count;
}

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

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

static struct bin_attribute ds1742_nvram_attr = {
	.attr = {
		.name = "nvram",
		.mode = S_IRUGO | S_IWUGO,
		.owner = THIS_MODULE,
	},
	.size = RTC_OFFSET,
	.read = ds1742_nvram_read,
	.write = ds1742_nvram_write,
};

static int __init ds1742_rtc_probe(struct platform_device *pdev)
{
	struct rtc_device *rtc;
	struct resource *res;
	unsigned int cen, sec;
	struct rtc_plat_data *pdata = NULL;
	void __iomem *ioaddr = NULL;
	int ret = 0;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENODEV;
	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return -ENOMEM;
	if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
		ret = -EBUSY;
		goto out;
	}
	pdata->baseaddr = res->start;
	ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
	if (!ioaddr) {
		ret = -ENOMEM;
		goto out;
	}
	pdata->ioaddr = ioaddr;

	/* turn RTC on if it was not on */
	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");

	rtc = rtc_device_register(pdev->name, &pdev->dev,
				  &ds1742_rtc_ops, THIS_MODULE);
	if (IS_ERR(rtc)) {
		ret = PTR_ERR(rtc);
		goto out;
	}
	pdata->rtc = rtc;
	pdata->last_jiffies = jiffies;
	platform_set_drvdata(pdev, pdata);
	sysfs_create_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);
	return 0;
 out:
	if (ioaddr)
		iounmap(ioaddr);
	if (pdata->baseaddr)
		release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
	kfree(pdata);
	return ret;
}

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

	sysfs_remove_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);
	rtc_device_unregister(pdata->rtc);
	iounmap(pdata->ioaddr);
	release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
	kfree(pdata);
	return 0;
}

static struct platform_driver ds1742_rtc_driver = {
	.probe		= ds1742_rtc_probe,
	.remove		= __devexit_p(ds1742_rtc_remove),
	.driver		= {
		.name	= "ds1742",
		.owner	= THIS_MODULE,
	},
};

static __init int ds1742_init(void)
{
	return platform_driver_register(&ds1742_rtc_driver);
}

static __exit void ds1742_exit(void)
{
	return platform_driver_unregister(&ds1742_rtc_driver);
}

module_init(ds1742_init);
module_exit(ds1742_exit);

MODULE_AUTHOR("Atsushi Nemoto <[email protected]>");
MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
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.
	9	*/
	10
	11	#include <linux/bcd.h>
	12	#include <linux/init.h>
	13	#include <linux/kernel.h>
	14	#include <linux/delay.h>
	15	#include <linux/jiffies.h>
	16	#include <linux/rtc.h>
	17	#include <linux/platform_device.h>
	18	#include <linux/io.h>
	19
	20	#define DRV_VERSION "0.1"
	21
	22	#define RTC_REG_SIZE 0x800
	23	#define RTC_OFFSET 0x7f8
	24
	25	#define RTC_CONTROL (RTC_OFFSET + 0)
	26	#define RTC_CENTURY (RTC_OFFSET + 0)
	27	#define RTC_SECONDS (RTC_OFFSET + 1)
	28	#define RTC_MINUTES (RTC_OFFSET + 2)
	29	#define RTC_HOURS (RTC_OFFSET + 3)
	30	#define RTC_DAY (RTC_OFFSET + 4)
	31	#define RTC_DATE (RTC_OFFSET + 5)
	32	#define RTC_MONTH (RTC_OFFSET + 6)
	33	#define RTC_YEAR (RTC_OFFSET + 7)
	34
	35	#define RTC_CENTURY_MASK 0x3f
	36	#define RTC_SECONDS_MASK 0x7f
	37	#define RTC_DAY_MASK 0x07
	38
	39	/* Bits in the Control/Century register */
	40	#define RTC_WRITE 0x80
	41	#define RTC_READ 0x40
	42
	43	/* Bits in the Seconds register */
	44	#define RTC_STOP 0x80
	45
	46	/* Bits in the Day register */
	47	#define RTC_BATT_FLAG 0x80
	48
	49	struct rtc_plat_data {
	50	struct rtc_device *rtc;
	51	void __iomem *ioaddr;
	52	unsigned long baseaddr;
	53	unsigned long last_jiffies;
	54	};
	55
	56	static int ds1742_rtc_set_time(struct device dev, struct rtc_time tm)
	57	{
	58	struct platform_device *pdev = to_platform_device(dev);
	59	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	60	void __iomem *ioaddr = pdata->ioaddr;
	61	u8 century;
	62
	63	century = BIN2BCD((tm->tm_year + 1900) / 100);
	64
65	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
66
67	writeb(BIN2BCD(tm->tm_year % 100), ioaddr + RTC_YEAR);
68	writeb(BIN2BCD(tm->tm_mon + 1), ioaddr + RTC_MONTH);
69	writeb(BIN2BCD(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
70	writeb(BIN2BCD(tm->tm_mday), ioaddr + RTC_DATE);
71	writeb(BIN2BCD(tm->tm_hour), ioaddr + RTC_HOURS);
72	writeb(BIN2BCD(tm->tm_min), ioaddr + RTC_MINUTES);
73	writeb(BIN2BCD(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
74
75	/* RTC_CENTURY and RTC_CONTROL share same register */
76	writeb(RTC_WRITE \| (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
77	writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
78	return 0;
79	}
80
81	static int ds1742_rtc_read_time(struct device dev, struct rtc_time tm)
82	{
83	struct platform_device *pdev = to_platform_device(dev);
84	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
85	void __iomem *ioaddr = pdata->ioaddr;
86	unsigned int year, month, day, hour, minute, second, week;
87	unsigned int century;
88
89	/* give enough time to update RTC in case of continuous read */
90	if (pdata->last_jiffies == jiffies)
91	msleep(1);
92	pdata->last_jiffies = jiffies;
93	writeb(RTC_READ, ioaddr + RTC_CONTROL);
94	second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
95	minute = readb(ioaddr + RTC_MINUTES);
96	hour = readb(ioaddr + RTC_HOURS);
97	day = readb(ioaddr + RTC_DATE);
98	week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
99	month = readb(ioaddr + RTC_MONTH);
100	year = readb(ioaddr + RTC_YEAR);
101	century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
102	writeb(0, ioaddr + RTC_CONTROL);
103	tm->tm_sec = BCD2BIN(second);
104	tm->tm_min = BCD2BIN(minute);
105	tm->tm_hour = BCD2BIN(hour);
106	tm->tm_mday = BCD2BIN(day);
107	tm->tm_wday = BCD2BIN(week);
108	tm->tm_mon = BCD2BIN(month) - 1;
109	/* year is 1900 + tm->tm_year */
110	tm->tm_year = BCD2BIN(year) + BCD2BIN(century) * 100 - 1900;
111
112	if (rtc_valid_tm(tm) < 0) {
113	dev_err(dev, "retrieved date/time is not valid.\n");
114	rtc_time_to_tm(0, tm);
115	}
116	return 0;
117	}
118
119	static struct rtc_class_ops ds1742_rtc_ops = {
120	.read_time = ds1742_rtc_read_time,
121	.set_time = ds1742_rtc_set_time,
122	};
123
124	static ssize_t ds1742_nvram_read(struct kobject kobj, char buf,
125	loff_t pos, size_t size)
126	{
127	struct platform_device *pdev =
128	to_platform_device(container_of(kobj, struct device, kobj));
129	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
130	void __iomem *ioaddr = pdata->ioaddr;
131	ssize_t count;
132
133	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
134	*buf++ = readb(ioaddr + pos++);
135	return count;
136	}
137
138	static ssize_t ds1742_nvram_write(struct kobject kobj, char buf,
139	loff_t pos, size_t size)
140	{
141	struct platform_device *pdev =
142	to_platform_device(container_of(kobj, struct device, kobj));
143	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
144	void __iomem *ioaddr = pdata->ioaddr;
145	ssize_t count;
146
147	for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
148	writeb(*buf++, ioaddr + pos++);
149	return count;
150	}
151
152	static struct bin_attribute ds1742_nvram_attr = {
153	.attr = {
154	.name = "nvram",
155	.mode = S_IRUGO \| S_IWUGO,
156	.owner = THIS_MODULE,
157	},
158	.size = RTC_OFFSET,
159	.read = ds1742_nvram_read,
160	.write = ds1742_nvram_write,
161	};
162
163	static int __init ds1742_rtc_probe(struct platform_device *pdev)
164	{
165	struct rtc_device *rtc;
166	struct resource *res;
167	unsigned int cen, sec;
168	struct rtc_plat_data *pdata = NULL;
169	void __iomem *ioaddr = NULL;
170	int ret = 0;
171
172	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
173	if (!res)
174	return -ENODEV;
175	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
176	if (!pdata)
177	return -ENOMEM;
178	if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
179	ret = -EBUSY;
180	goto out;
181	}
182	pdata->baseaddr = res->start;
183	ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
184	if (!ioaddr) {
185	ret = -ENOMEM;
186	goto out;
187	}
188	pdata->ioaddr = ioaddr;
189
190	/* turn RTC on if it was not on */
191	sec = readb(ioaddr + RTC_SECONDS);
192	if (sec & RTC_STOP) {
193	sec &= RTC_SECONDS_MASK;
194	cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
195	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
196	writeb(sec, ioaddr + RTC_SECONDS);
197	writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
198	}
199	if (readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG)
200	dev_warn(&pdev->dev, "voltage-low detected.\n");
201
202	rtc = rtc_device_register(pdev->name, &pdev->dev,
203	&ds1742_rtc_ops, THIS_MODULE);
204	if (IS_ERR(rtc)) {
205	ret = PTR_ERR(rtc);
206	goto out;
207	}
208	pdata->rtc = rtc;
209	pdata->last_jiffies = jiffies;
210	platform_set_drvdata(pdev, pdata);
211	sysfs_create_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);
212	return 0;
213	out:
214	if (ioaddr)
215	iounmap(ioaddr);
216	if (pdata->baseaddr)
217	release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
218	kfree(pdata);
219	return ret;
220	}
221
222	static int __devexit ds1742_rtc_remove(struct platform_device *pdev)
223	{
224	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
225
226	sysfs_remove_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);
227	rtc_device_unregister(pdata->rtc);
228	iounmap(pdata->ioaddr);
229	release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
230	kfree(pdata);
231	return 0;
232	}
233
234	static struct platform_driver ds1742_rtc_driver = {
235	.probe = ds1742_rtc_probe,
236	.remove = __devexit_p(ds1742_rtc_remove),
237	.driver = {
238	.name = "ds1742",
239	.owner = THIS_MODULE,
240	},
241	};
242
243	static __init int ds1742_init(void)
244	{
245	return platform_driver_register(&ds1742_rtc_driver);
246	}
247
248	static __exit void ds1742_exit(void)
249	{
250	return platform_driver_unregister(&ds1742_rtc_driver);
251	}
252
253	module_init(ds1742_init);
254	module_exit(ds1742_exit);
255
256	MODULE_AUTHOR("Atsushi Nemoto <[email protected]>");
257	MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
258	MODULE_LICENSE("GPL");
259	MODULE_VERSION(DRV_VERSION);