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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * An rtc driver for the Dallas DS1742
 *
 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
 *
 * 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;

	ioaddr = devm_platform_get_and_ioremap_resource(pdev, 0, &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;

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

	devm_rtc_nvmem_register(rtc, &nvmem_cfg);

	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
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
5ec3e4b7 AN	2	/*
	3	* An rtc driver for the Dallas DS1742
	4	*
	5	* Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
	6	*
f9231a0c TER	7	* Copyright (C) 2006 Torsten Ertbjerg Rasmussen <tr@newtec.dk>
	8	* - nvram size determined from resource
	9	* - this ds1742 driver now supports ds1743.
5ec3e4b7 AN	10	*/
	11
	12	#include <linux/bcd.h>
5ec3e4b7	13	#include <linux/kernel.h>
5a0e3ad6	14	#include <linux/gfp.h>
5ec3e4b7 AN	15	#include <linux/delay.h>
	16	#include <linux/jiffies.h>
	17	#include <linux/rtc.h>
663b3524 AS	18	#include <linux/of.h>
663b3524 AS	19	#include <linux/of_device.h>
5ec3e4b7 AN	20	#include <linux/platform_device.h>
5ec3e4b7 AN	21	#include <linux/io.h>
2113852b	22	#include <linux/module.h>
5ec3e4b7	23
f9231a0c	24	#define RTC_SIZE 8
5ec3e4b7	25
f9231a0c TER	26	#define RTC_CONTROL 0
	27	#define RTC_CENTURY 0
	28	#define RTC_SECONDS 1
	29	#define RTC_MINUTES 2
	30	#define RTC_HOURS 3
	31	#define RTC_DAY 4
	32	#define RTC_DATE 5
	33	#define RTC_MONTH 6
	34	#define RTC_YEAR 7
5ec3e4b7 AN	35
	36	#define RTC_CENTURY_MASK 0x3f
	37	#define RTC_SECONDS_MASK 0x7f
	38	#define RTC_DAY_MASK 0x07
	39
	40	/* Bits in the Control/Century register */
	41	#define RTC_WRITE 0x80
	42	#define RTC_READ 0x40
	43
	44	/* Bits in the Seconds register */
	45	#define RTC_STOP 0x80
	46
	47	/* Bits in the Day register */
	48	#define RTC_BATT_FLAG 0x80
	49
	50	struct rtc_plat_data {
f9231a0c TER	51	void __iomem *ioaddr_nvram;
f9231a0c TER	52	void __iomem *ioaddr_rtc;
5ec3e4b7 AN	53	unsigned long last_jiffies;
	54	};
	55
	56	static int ds1742_rtc_set_time(struct device dev, struct rtc_time tm)
	57	{
85368bb9	58	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
f9231a0c	59	void __iomem *ioaddr = pdata->ioaddr_rtc;
5ec3e4b7 AN	60	u8 century;
5ec3e4b7 AN	61
fe20ba70	62	century = bin2bcd((tm->tm_year + 1900) / 100);
5ec3e4b7 AN	63
	64	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
	65
fe20ba70 AB	66	writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
	67	writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
	68	writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
	69	writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
	70	writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
	71	writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
	72	writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
5ec3e4b7 AN	73
	74	/* RTC_CENTURY and RTC_CONTROL share same register */
	75	writeb(RTC_WRITE \| (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
	76	writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
	77	return 0;
	78	}
	79
	80	static int ds1742_rtc_read_time(struct device dev, struct rtc_time tm)
	81	{
85368bb9	82	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
f9231a0c	83	void __iomem *ioaddr = pdata->ioaddr_rtc;
5ec3e4b7 AN	84	unsigned int year, month, day, hour, minute, second, week;
	85	unsigned int century;
	86
	87	/* give enough time to update RTC in case of continuous read */
	88	if (pdata->last_jiffies == jiffies)
	89	msleep(1);
	90	pdata->last_jiffies = jiffies;
	91	writeb(RTC_READ, ioaddr + RTC_CONTROL);
	92	second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
	93	minute = readb(ioaddr + RTC_MINUTES);
	94	hour = readb(ioaddr + RTC_HOURS);
	95	day = readb(ioaddr + RTC_DATE);
	96	week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
	97	month = readb(ioaddr + RTC_MONTH);
	98	year = readb(ioaddr + RTC_YEAR);
	99	century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
	100	writeb(0, ioaddr + RTC_CONTROL);
fe20ba70 AB	101	tm->tm_sec = bcd2bin(second);
	102	tm->tm_min = bcd2bin(minute);
	103	tm->tm_hour = bcd2bin(hour);
	104	tm->tm_mday = bcd2bin(day);
	105	tm->tm_wday = bcd2bin(week);
	106	tm->tm_mon = bcd2bin(month) - 1;
5ec3e4b7	107	/* year is 1900 + tm->tm_year */
fe20ba70	108	tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
5ec3e4b7	109
22652ba7	110	return 0;
5ec3e4b7 AN	111	}
5ec3e4b7 AN	112
ff8371ac	113	static const struct rtc_class_ops ds1742_rtc_ops = {
5ec3e4b7 AN	114	.read_time = ds1742_rtc_read_time,
	115	.set_time = ds1742_rtc_set_time,
	116	};
	117
87c78d95 AB	118	static int ds1742_nvram_read(void priv, unsigned int pos, void val,
87c78d95 AB	119	size_t bytes)
5ec3e4b7	120	{
87c78d95	121	struct rtc_plat_data *pdata = priv;
f9231a0c	122	void __iomem *ioaddr = pdata->ioaddr_nvram;
87c78d95	123	u8 *buf = val;
5ec3e4b7	124
87c78d95	125	for (; bytes; bytes--)
5ec3e4b7	126	*buf++ = readb(ioaddr + pos++);
87c78d95	127	return 0;
5ec3e4b7 AN	128	}
5ec3e4b7 AN	129
87c78d95 AB	130	static int ds1742_nvram_write(void priv, unsigned int pos, void val,
87c78d95 AB	131	size_t bytes)
5ec3e4b7	132	{
87c78d95	133	struct rtc_plat_data *pdata = priv;
f9231a0c	134	void __iomem *ioaddr = pdata->ioaddr_nvram;
87c78d95	135	u8 *buf = val;
5ec3e4b7	136
87c78d95	137	for (; bytes; bytes--)
5ec3e4b7	138	writeb(*buf++, ioaddr + pos++);
87c78d95	139	return 0;
5ec3e4b7 AN	140	}
5ec3e4b7 AN	141
5a167f45	142	static int ds1742_rtc_probe(struct platform_device *pdev)
5ec3e4b7 AN	143	{
	144	struct rtc_device *rtc;
	145	struct resource *res;
	146	unsigned int cen, sec;
ac18eb62 AN	147	struct rtc_plat_data *pdata;
ac18eb62 AN	148	void __iomem *ioaddr;
5ec3e4b7	149	int ret = 0;
87c78d95 AB	150	struct nvmem_config nvmem_cfg = {
87c78d95 AB	151	.name = "ds1742_nvram",
87c78d95 AB	152	.reg_read = ds1742_nvram_read,
	153	.reg_write = ds1742_nvram_write,
	154	};
	155
5ec3e4b7	156
ac18eb62	157	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
5ec3e4b7 AN	158	if (!pdata)
5ec3e4b7 AN	159	return -ENOMEM;
25e2818e	160
e88f319a	161	ioaddr = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
25e2818e AS	162	if (IS_ERR(ioaddr))
25e2818e AS	163	return PTR_ERR(ioaddr);
ac18eb62	164
f9231a0c	165	pdata->ioaddr_nvram = ioaddr;
87c78d95	166	pdata->ioaddr_rtc = ioaddr + resource_size(res) - RTC_SIZE;
5ec3e4b7	167
87c78d95 AB	168	nvmem_cfg.size = resource_size(res) - RTC_SIZE;
87c78d95 AB	169	nvmem_cfg.priv = pdata;
3a729700	170
5ec3e4b7	171	/* turn RTC on if it was not on */
f9231a0c	172	ioaddr = pdata->ioaddr_rtc;
5ec3e4b7 AN	173	sec = readb(ioaddr + RTC_SECONDS);
	174	if (sec & RTC_STOP) {
	175	sec &= RTC_SECONDS_MASK;
	176	cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
	177	writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
	178	writeb(sec, ioaddr + RTC_SECONDS);
	179	writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
	180	}
391b1fe6	181	if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
5ec3e4b7 AN	182	dev_warn(&pdev->dev, "voltage-low detected.\n");
5ec3e4b7 AN	183
ac18eb62 AN	184	pdata->last_jiffies = jiffies;
ac18eb62 AN	185	platform_set_drvdata(pdev, pdata);
1358e7b2 AB	186
1358e7b2 AB	187	rtc = devm_rtc_allocate_device(&pdev->dev);
ac18eb62 AN	188	if (IS_ERR(rtc))
ac18eb62 AN	189	return PTR_ERR(rtc);
3a729700	190
1358e7b2 AB	191	rtc->ops = &ds1742_rtc_ops;
1358e7b2 AB	192
fdcfd854	193	ret = devm_rtc_register_device(rtc);
1358e7b2 AB	194	if (ret)
	195	return ret;
	196
6746bc09	197	devm_rtc_nvmem_register(rtc, &nvmem_cfg);
5ec3e4b7	198
5ec3e4b7 AN	199	return 0;
	200	}
	201
9d203572	202	static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
663b3524 AS	203	{ .compatible = "maxim,ds1742", },
	204	{ }
	205	};
	206	MODULE_DEVICE_TABLE(of, ds1742_rtc_of_match);
	207
5ec3e4b7 AN	208	static struct platform_driver ds1742_rtc_driver = {
5ec3e4b7 AN	209	.probe = ds1742_rtc_probe,
5ec3e4b7	210	.driver = {
a95e23a2	211	.name = "rtc-ds1742",
3710f597	212	.of_match_table = of_match_ptr(ds1742_rtc_of_match),
5ec3e4b7 AN	213	},
	214	};
	215
0c4eae66	216	module_platform_driver(ds1742_rtc_driver);
5ec3e4b7 AN	217
	218	MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
	219	MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
	220	MODULE_LICENSE("GPL");
ad28a07b	221	MODULE_ALIAS("platform:rtc-ds1742");