[linux-block.git] / drivers / rtc / rtc-ds1347.c

// SPDX-License-Identifier: GPL-2.0-only
/* rtc-ds1347.c
 *
 * Driver for Dallas Semiconductor DS1347 Low Current, SPI Compatible
 * Real Time Clock
 *
 * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/spi/spi.h>
#include <linux/bcd.h>
#include <linux/regmap.h>

/* Registers in ds1347 rtc */

#define DS1347_SECONDS_REG	0x01
#define DS1347_MINUTES_REG	0x03
#define DS1347_HOURS_REG	0x05
#define DS1347_DATE_REG		0x07
#define DS1347_MONTH_REG	0x09
#define DS1347_DAY_REG		0x0B
#define DS1347_YEAR_REG		0x0D
#define DS1347_CONTROL_REG	0x0F
#define DS1347_CENTURY_REG	0x13
#define DS1347_STATUS_REG	0x17
#define DS1347_CLOCK_BURST	0x3F

#define DS1347_WP_BIT		BIT(7)

#define DS1347_NEOSC_BIT	BIT(7)
#define DS1347_OSF_BIT		BIT(2)

static const struct regmap_range ds1347_ranges[] = {
	{
		.range_min = DS1347_SECONDS_REG,
		.range_max = DS1347_STATUS_REG,
	},
};

static const struct regmap_access_table ds1347_access_table = {
	.yes_ranges = ds1347_ranges,
	.n_yes_ranges = ARRAY_SIZE(ds1347_ranges),
};

static int ds1347_read_time(struct device *dev, struct rtc_time *dt)
{
	struct regmap *map = dev_get_drvdata(dev);
	unsigned int status, century, secs;
	unsigned char buf[8];
	int err;

	err = regmap_read(map, DS1347_STATUS_REG, &status);
	if (err)
		return err;

	if (status & DS1347_OSF_BIT)
		return -EINVAL;

	do {
		err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8);
		if (err)
			return err;

		err = regmap_read(map, DS1347_CENTURY_REG, &century);
		if (err)
			return err;

		err = regmap_read(map, DS1347_SECONDS_REG, &secs);
		if (err)
			return err;
	} while (buf[0] != secs);

	dt->tm_sec = bcd2bin(buf[0]);
	dt->tm_min = bcd2bin(buf[1] & 0x7f);
	dt->tm_hour = bcd2bin(buf[2] & 0x3F);
	dt->tm_mday = bcd2bin(buf[3]);
	dt->tm_mon = bcd2bin(buf[4]) - 1;
	dt->tm_wday = bcd2bin(buf[5]) - 1;
	dt->tm_year = (bcd2bin(century) * 100) + bcd2bin(buf[6]) - 1900;

	return 0;
}

static int ds1347_set_time(struct device *dev, struct rtc_time *dt)
{
	struct regmap *map = dev_get_drvdata(dev);
	unsigned int century;
	unsigned char buf[8];
	int err;

	err = regmap_update_bits(map, DS1347_STATUS_REG,
				 DS1347_NEOSC_BIT, DS1347_NEOSC_BIT);
	if (err)
		return err;

	buf[0] = bin2bcd(dt->tm_sec);
	buf[1] = bin2bcd(dt->tm_min);
	buf[2] = (bin2bcd(dt->tm_hour) & 0x3F);
	buf[3] = bin2bcd(dt->tm_mday);
	buf[4] = bin2bcd(dt->tm_mon + 1);
	buf[5] = bin2bcd(dt->tm_wday + 1);
	buf[6] = bin2bcd(dt->tm_year % 100);
	buf[7] = bin2bcd(0x00);

	err = regmap_bulk_write(map, DS1347_CLOCK_BURST, buf, 8);
	if (err)
		return err;

	century = (dt->tm_year / 100) + 19;
	err = regmap_write(map, DS1347_CENTURY_REG, bin2bcd(century));
	if (err)
		return err;

	return regmap_update_bits(map, DS1347_STATUS_REG,
				  DS1347_NEOSC_BIT | DS1347_OSF_BIT, 0);
}

static const struct rtc_class_ops ds1347_rtc_ops = {
	.read_time = ds1347_read_time,
	.set_time = ds1347_set_time,
};

static int ds1347_probe(struct spi_device *spi)
{
	struct rtc_device *rtc;
	struct regmap_config config;
	struct regmap *map;
	int err;

	memset(&config, 0, sizeof(config));
	config.reg_bits = 8;
	config.val_bits = 8;
	config.read_flag_mask = 0x80;
	config.max_register = 0x3F;
	config.wr_table = &ds1347_access_table;

	/* spi setup with ds1347 in mode 3 and bits per word as 8 */
	spi->mode = SPI_MODE_3;
	spi->bits_per_word = 8;
	spi_setup(spi);

	map = devm_regmap_init_spi(spi, &config);

	if (IS_ERR(map)) {
		dev_err(&spi->dev, "ds1347 regmap init spi failed\n");
		return PTR_ERR(map);
	}

	spi_set_drvdata(spi, map);

	/* Disable the write protect of rtc */
	err = regmap_update_bits(map, DS1347_CONTROL_REG, DS1347_WP_BIT, 0);
	if (err)
		return err;

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

	rtc->ops = &ds1347_rtc_ops;
	rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
	rtc->range_max = RTC_TIMESTAMP_END_9999;

	return devm_rtc_register_device(rtc);
}

static struct spi_driver ds1347_driver = {
	.driver = {
		.name = "ds1347",
	},
	.probe = ds1347_probe,
};

module_spi_driver(ds1347_driver);

MODULE_DESCRIPTION("DS1347 SPI RTC DRIVER");
MODULE_AUTHOR("Raghavendra C Ganiga <ravi23ganiga@gmail.com>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
617b26a0 RG	2	/* rtc-ds1347.c
	3	*
	4	* Driver for Dallas Semiconductor DS1347 Low Current, SPI Compatible
	5	* Real Time Clock
	6	*
	7	* Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
617b26a0 RG	8	*/
	9
	10	#include <linux/init.h>
	11	#include <linux/module.h>
	12	#include <linux/device.h>
	13	#include <linux/platform_device.h>
	14	#include <linux/rtc.h>
	15	#include <linux/spi/spi.h>
	16	#include <linux/bcd.h>
ee85bb5b	17	#include <linux/regmap.h>
617b26a0 RG	18
	19	/* Registers in ds1347 rtc */
	20
	21	#define DS1347_SECONDS_REG 0x01
	22	#define DS1347_MINUTES_REG 0x03
	23	#define DS1347_HOURS_REG 0x05
	24	#define DS1347_DATE_REG 0x07
	25	#define DS1347_MONTH_REG 0x09
	26	#define DS1347_DAY_REG 0x0B
	27	#define DS1347_YEAR_REG 0x0D
	28	#define DS1347_CONTROL_REG 0x0F
147dae76	29	#define DS1347_CENTURY_REG 0x13
617b26a0 RG	30	#define DS1347_STATUS_REG 0x17
	31	#define DS1347_CLOCK_BURST 0x3F
	32
860c45b5 AB	33	#define DS1347_WP_BIT BIT(7)
860c45b5 AB	34
d9dcfa5f AB	35	#define DS1347_NEOSC_BIT BIT(7)
	36	#define DS1347_OSF_BIT BIT(2)
	37
ee85bb5b RG	38	static const struct regmap_range ds1347_ranges[] = {
	39	{
	40	.range_min = DS1347_SECONDS_REG,
	41	.range_max = DS1347_STATUS_REG,
	42	},
	43	};
617b26a0	44
ee85bb5b RG	45	static const struct regmap_access_table ds1347_access_table = {
	46	.yes_ranges = ds1347_ranges,
	47	.n_yes_ranges = ARRAY_SIZE(ds1347_ranges),
	48	};
617b26a0 RG	49
	50	static int ds1347_read_time(struct device dev, struct rtc_time dt)
	51	{
ff7f9e05	52	struct regmap *map = dev_get_drvdata(dev);
147dae76	53	unsigned int status, century, secs;
617b26a0	54	unsigned char buf[8];
147dae76	55	int err;
617b26a0	56
d9dcfa5f AB	57	err = regmap_read(map, DS1347_STATUS_REG, &status);
	58	if (err)
	59	return err;
	60
	61	if (status & DS1347_OSF_BIT)
	62	return -EINVAL;
	63
147dae76 AB	64	do {
	65	err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8);
	66	if (err)
	67	return err;
	68
	69	err = regmap_read(map, DS1347_CENTURY_REG, &century);
	70	if (err)
	71	return err;
	72
	73	err = regmap_read(map, DS1347_SECONDS_REG, &secs);
	74	if (err)
	75	return err;
	76	} while (buf[0] != secs);
617b26a0 RG	77
617b26a0 RG	78	dt->tm_sec = bcd2bin(buf[0]);
088443c7	79	dt->tm_min = bcd2bin(buf[1] & 0x7f);
617b26a0 RG	80	dt->tm_hour = bcd2bin(buf[2] & 0x3F);
	81	dt->tm_mday = bcd2bin(buf[3]);
	82	dt->tm_mon = bcd2bin(buf[4]) - 1;
	83	dt->tm_wday = bcd2bin(buf[5]) - 1;
147dae76	84	dt->tm_year = (bcd2bin(century) * 100) + bcd2bin(buf[6]) - 1900;
617b26a0	85
22652ba7	86	return 0;
617b26a0 RG	87	}
	88
	89	static int ds1347_set_time(struct device dev, struct rtc_time dt)
	90	{
ff7f9e05	91	struct regmap *map = dev_get_drvdata(dev);
147dae76	92	unsigned int century;
ee85bb5b	93	unsigned char buf[8];
d9dcfa5f AB	94	int err;
	95
	96	err = regmap_update_bits(map, DS1347_STATUS_REG,
	97	DS1347_NEOSC_BIT, DS1347_NEOSC_BIT);
	98	if (err)
	99	return err;
ee85bb5b	100
ee85bb5b RG	101	buf[0] = bin2bcd(dt->tm_sec);
	102	buf[1] = bin2bcd(dt->tm_min);
	103	buf[2] = (bin2bcd(dt->tm_hour) & 0x3F);
	104	buf[3] = bin2bcd(dt->tm_mday);
	105	buf[4] = bin2bcd(dt->tm_mon + 1);
	106	buf[5] = bin2bcd(dt->tm_wday + 1);
147dae76	107	buf[6] = bin2bcd(dt->tm_year % 100);
ee85bb5b	108	buf[7] = bin2bcd(0x00);
617b26a0	109
d9dcfa5f AB	110	err = regmap_bulk_write(map, DS1347_CLOCK_BURST, buf, 8);
	111	if (err)
	112	return err;
	113
147dae76	114	century = (dt->tm_year / 100) + 19;
4dfe05bd	115	err = regmap_write(map, DS1347_CENTURY_REG, bin2bcd(century));
147dae76 AB	116	if (err)
	117	return err;
	118
d9dcfa5f AB	119	return regmap_update_bits(map, DS1347_STATUS_REG,
d9dcfa5f AB	120	DS1347_NEOSC_BIT \| DS1347_OSF_BIT, 0);
617b26a0 RG	121	}
	122
	123	static const struct rtc_class_ops ds1347_rtc_ops = {
	124	.read_time = ds1347_read_time,
	125	.set_time = ds1347_set_time,
	126	};
	127
	128	static int ds1347_probe(struct spi_device *spi)
	129	{
	130	struct rtc_device *rtc;
ee85bb5b RG	131	struct regmap_config config;
ee85bb5b RG	132	struct regmap *map;
860c45b5	133	int err;
617b26a0	134
ee85bb5b RG	135	memset(&config, 0, sizeof(config));
	136	config.reg_bits = 8;
	137	config.val_bits = 8;
	138	config.read_flag_mask = 0x80;
	139	config.max_register = 0x3F;
	140	config.wr_table = &ds1347_access_table;
	141
617b26a0 RG	142	/* spi setup with ds1347 in mode 3 and bits per word as 8 */
	143	spi->mode = SPI_MODE_3;
	144	spi->bits_per_word = 8;
	145	spi_setup(spi);
	146
ee85bb5b RG	147	map = devm_regmap_init_spi(spi, &config);
	148
	149	if (IS_ERR(map)) {
	150	dev_err(&spi->dev, "ds1347 regmap init spi failed\n");
	151	return PTR_ERR(map);
	152	}
	153
	154	spi_set_drvdata(spi, map);
	155
617b26a0	156	/* Disable the write protect of rtc */
860c45b5 AB	157	err = regmap_update_bits(map, DS1347_CONTROL_REG, DS1347_WP_BIT, 0);
	158	if (err)
	159	return err;
617b26a0	160
554692d5	161	rtc = devm_rtc_allocate_device(&spi->dev);
617b26a0 RG	162	if (IS_ERR(rtc))
	163	return PTR_ERR(rtc);
	164
554692d5	165	rtc->ops = &ds1347_rtc_ops;
3ce20a23 AB	166	rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
3ce20a23 AB	167	rtc->range_max = RTC_TIMESTAMP_END_9999;
554692d5	168
fdcfd854	169	return devm_rtc_register_device(rtc);
617b26a0 RG	170	}
	171
	172	static struct spi_driver ds1347_driver = {
	173	.driver = {
	174	.name = "ds1347",
617b26a0 RG	175	},
	176	.probe = ds1347_probe,
	177	};
	178
	179	module_spi_driver(ds1347_driver);
	180
	181	MODULE_DESCRIPTION("DS1347 SPI RTC DRIVER");
	182	MODULE_AUTHOR("Raghavendra C Ganiga <ravi23ganiga@gmail.com>");
	183	MODULE_LICENSE("GPL v2");