[linux-block.git] / drivers / rtc / rtc-ds1390.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * rtc-ds1390.c -- driver for the Dallas/Maxim DS1390/93/94 SPI RTC
 *
 * Copyright (C) 2008 Mercury IMC Ltd
 * Written by Mark Jackson <mpfj@mimc.co.uk>
 *
 * NOTE: Currently this driver only supports the bare minimum for read
 * and write the RTC. The extra features provided by the chip family
 * (alarms, trickle charger, different control registers) are unavailable.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/spi/spi.h>
#include <linux/bcd.h>
#include <linux/slab.h>
#include <linux/of.h>

#define DS1390_REG_100THS		0x00
#define DS1390_REG_SECONDS		0x01
#define DS1390_REG_MINUTES		0x02
#define DS1390_REG_HOURS		0x03
#define DS1390_REG_DAY			0x04
#define DS1390_REG_DATE			0x05
#define DS1390_REG_MONTH_CENT		0x06
#define DS1390_REG_YEAR			0x07

#define DS1390_REG_ALARM_100THS		0x08
#define DS1390_REG_ALARM_SECONDS	0x09
#define DS1390_REG_ALARM_MINUTES	0x0A
#define DS1390_REG_ALARM_HOURS		0x0B
#define DS1390_REG_ALARM_DAY_DATE	0x0C

#define DS1390_REG_CONTROL		0x0D
#define DS1390_REG_STATUS		0x0E
#define DS1390_REG_TRICKLE		0x0F

#define DS1390_TRICKLE_CHARGER_ENABLE	0xA0
#define DS1390_TRICKLE_CHARGER_250_OHM	0x01
#define DS1390_TRICKLE_CHARGER_2K_OHM	0x02
#define DS1390_TRICKLE_CHARGER_4K_OHM	0x03
#define DS1390_TRICKLE_CHARGER_NO_DIODE	0x04
#define DS1390_TRICKLE_CHARGER_DIODE	0x08

struct ds1390 {
	struct rtc_device *rtc;
	u8 txrx_buf[9];	/* cmd + 8 registers */
};

static void ds1390_set_reg(struct device *dev, unsigned char address,
			   unsigned char data)
{
	struct spi_device *spi = to_spi_device(dev);
	unsigned char buf[2];

	/* MSB must be '1' to write */
	buf[0] = address | 0x80;
	buf[1] = data;

	spi_write(spi, buf, 2);
}

static int ds1390_get_reg(struct device *dev, unsigned char address,
				unsigned char *data)
{
	struct spi_device *spi = to_spi_device(dev);
	struct ds1390 *chip = dev_get_drvdata(dev);
	int status;

	if (!data)
		return -EINVAL;

	/* Clear MSB to indicate read */
	chip->txrx_buf[0] = address & 0x7f;
	/* do the i/o */
	status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1);
	if (status != 0)
		return status;

	*data = chip->txrx_buf[0];

	return 0;
}

static void ds1390_trickle_of_init(struct spi_device *spi)
{
	u32 ohms = 0;
	u8 value;

	if (of_property_read_u32(spi->dev.of_node, "trickle-resistor-ohms",
				 &ohms))
		goto out;

	/* Enable charger */
	value = DS1390_TRICKLE_CHARGER_ENABLE;
	if (of_property_read_bool(spi->dev.of_node, "trickle-diode-disable"))
		value |= DS1390_TRICKLE_CHARGER_NO_DIODE;
	else
		value |= DS1390_TRICKLE_CHARGER_DIODE;

	/* Resistor select */
	switch (ohms) {
	case 250:
		value |= DS1390_TRICKLE_CHARGER_250_OHM;
		break;
	case 2000:
		value |= DS1390_TRICKLE_CHARGER_2K_OHM;
		break;
	case 4000:
		value |= DS1390_TRICKLE_CHARGER_4K_OHM;
		break;
	default:
		dev_warn(&spi->dev,
			 "Unsupported ohm value %02ux in dt\n", ohms);
		return;
	}

	ds1390_set_reg(&spi->dev, DS1390_REG_TRICKLE, value);

out:
	return;
}

static int ds1390_read_time(struct device *dev, struct rtc_time *dt)
{
	struct spi_device *spi = to_spi_device(dev);
	struct ds1390 *chip = dev_get_drvdata(dev);
	int status;

	/* build the message */
	chip->txrx_buf[0] = DS1390_REG_SECONDS;

	/* do the i/o */
	status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8);
	if (status != 0)
		return status;

	/* The chip sends data in this order:
	 * Seconds, Minutes, Hours, Day, Date, Month / Century, Year */
	dt->tm_sec	= bcd2bin(chip->txrx_buf[0]);
	dt->tm_min	= bcd2bin(chip->txrx_buf[1]);
	dt->tm_hour	= bcd2bin(chip->txrx_buf[2]);
	dt->tm_wday	= bcd2bin(chip->txrx_buf[3]);
	dt->tm_mday	= bcd2bin(chip->txrx_buf[4]);
	/* mask off century bit */
	dt->tm_mon	= bcd2bin(chip->txrx_buf[5] & 0x7f) - 1;
	/* adjust for century bit */
	dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0);

	return 0;
}

static int ds1390_set_time(struct device *dev, struct rtc_time *dt)
{
	struct spi_device *spi = to_spi_device(dev);
	struct ds1390 *chip = dev_get_drvdata(dev);

	/* build the message */
	chip->txrx_buf[0] = DS1390_REG_SECONDS | 0x80;
	chip->txrx_buf[1] = bin2bcd(dt->tm_sec);
	chip->txrx_buf[2] = bin2bcd(dt->tm_min);
	chip->txrx_buf[3] = bin2bcd(dt->tm_hour);
	chip->txrx_buf[4] = bin2bcd(dt->tm_wday);
	chip->txrx_buf[5] = bin2bcd(dt->tm_mday);
	chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) |
				((dt->tm_year > 99) ? 0x80 : 0x00);
	chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100);

	/* do the i/o */
	return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0);
}

static const struct rtc_class_ops ds1390_rtc_ops = {
	.read_time	= ds1390_read_time,
	.set_time	= ds1390_set_time,
};

static int ds1390_probe(struct spi_device *spi)
{
	unsigned char tmp;
	struct ds1390 *chip;
	int res;

	spi->mode = SPI_MODE_3;
	spi->bits_per_word = 8;
	spi_setup(spi);

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

	spi_set_drvdata(spi, chip);

	res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp);
	if (res != 0) {
		dev_err(&spi->dev, "unable to read device\n");
		return res;
	}

	if (spi->dev.of_node)
		ds1390_trickle_of_init(spi);

	chip->rtc = devm_rtc_device_register(&spi->dev, "ds1390",
					&ds1390_rtc_ops, THIS_MODULE);
	if (IS_ERR(chip->rtc)) {
		dev_err(&spi->dev, "unable to register device\n");
		res = PTR_ERR(chip->rtc);
	}

	return res;
}

static const struct of_device_id ds1390_of_match[] __maybe_unused = {
	{ .compatible = "dallas,ds1390" },
	{}
};
MODULE_DEVICE_TABLE(of, ds1390_of_match);

static const struct spi_device_id ds1390_spi_ids[] = {
	{ .name = "ds1390" },
	{}
};
MODULE_DEVICE_TABLE(spi, ds1390_spi_ids);

static struct spi_driver ds1390_driver = {
	.driver = {
		.name	= "rtc-ds1390",
		.of_match_table = of_match_ptr(ds1390_of_match),
	},
	.probe	= ds1390_probe,
	.id_table = ds1390_spi_ids,
};

module_spi_driver(ds1390_driver);

MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver");
MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:rtc-ds1390");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
06de1808	2	/*
7b9b2ef1	3	* rtc-ds1390.c -- driver for the Dallas/Maxim DS1390/93/94 SPI RTC
06de1808 MJ	4	*
	5	* Copyright (C) 2008 Mercury IMC Ltd
	6	* Written by Mark Jackson <mpfj@mimc.co.uk>
	7	*
7b9b2ef1 AZ	8	* NOTE: Currently this driver only supports the bare minimum for read
7b9b2ef1 AZ	9	* and write the RTC. The extra features provided by the chip family
06de1808 MJ	10	* (alarms, trickle charger, different control registers) are unavailable.
	11	*/
	12
7b9b2ef1 AZ	13	#include <linux/init.h>
7b9b2ef1 AZ	14	#include <linux/module.h>
06de1808 MJ	15	#include <linux/platform_device.h>
	16	#include <linux/rtc.h>
	17	#include <linux/spi/spi.h>
	18	#include <linux/bcd.h>
5a0e3ad6	19	#include <linux/slab.h>
fa395fb8	20	#include <linux/of.h>
06de1808 MJ	21
	22	#define DS1390_REG_100THS 0x00
	23	#define DS1390_REG_SECONDS 0x01
	24	#define DS1390_REG_MINUTES 0x02
	25	#define DS1390_REG_HOURS 0x03
	26	#define DS1390_REG_DAY 0x04
	27	#define DS1390_REG_DATE 0x05
	28	#define DS1390_REG_MONTH_CENT 0x06
	29	#define DS1390_REG_YEAR 0x07
	30
	31	#define DS1390_REG_ALARM_100THS 0x08
	32	#define DS1390_REG_ALARM_SECONDS 0x09
	33	#define DS1390_REG_ALARM_MINUTES 0x0A
	34	#define DS1390_REG_ALARM_HOURS 0x0B
	35	#define DS1390_REG_ALARM_DAY_DATE 0x0C
	36
	37	#define DS1390_REG_CONTROL 0x0D
	38	#define DS1390_REG_STATUS 0x0E
	39	#define DS1390_REG_TRICKLE 0x0F
	40
fa395fb8 IG	41	#define DS1390_TRICKLE_CHARGER_ENABLE 0xA0
	42	#define DS1390_TRICKLE_CHARGER_250_OHM 0x01
	43	#define DS1390_TRICKLE_CHARGER_2K_OHM 0x02
	44	#define DS1390_TRICKLE_CHARGER_4K_OHM 0x03
	45	#define DS1390_TRICKLE_CHARGER_NO_DIODE 0x04
	46	#define DS1390_TRICKLE_CHARGER_DIODE 0x08
	47
06de1808 MJ	48	struct ds1390 {
	49	struct rtc_device *rtc;
	50	u8 txrx_buf[9]; /* cmd + 8 registers */
	51	};
	52
fa395fb8 IG	53	static void ds1390_set_reg(struct device *dev, unsigned char address,
	54	unsigned char data)
	55	{
	56	struct spi_device *spi = to_spi_device(dev);
	57	unsigned char buf[2];
	58
	59	/* MSB must be '1' to write */
	60	buf[0] = address \| 0x80;
	61	buf[1] = data;
	62
	63	spi_write(spi, buf, 2);
	64	}
	65
06de1808 MJ	66	static int ds1390_get_reg(struct device *dev, unsigned char address,
	67	unsigned char *data)
	68	{
	69	struct spi_device *spi = to_spi_device(dev);
	70	struct ds1390 *chip = dev_get_drvdata(dev);
	71	int status;
	72
	73	if (!data)
	74	return -EINVAL;
	75
	76	/* Clear MSB to indicate read */
	77	chip->txrx_buf[0] = address & 0x7f;
	78	/* do the i/o */
	79	status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1);
	80	if (status != 0)
	81	return status;
	82
2ec68825	83	*data = chip->txrx_buf[0];
06de1808 MJ	84
	85	return 0;
	86	}
	87
fa395fb8 IG	88	static void ds1390_trickle_of_init(struct spi_device *spi)
	89	{
	90	u32 ohms = 0;
	91	u8 value;
	92
	93	if (of_property_read_u32(spi->dev.of_node, "trickle-resistor-ohms",
	94	&ohms))
	95	goto out;
	96
	97	/* Enable charger */
	98	value = DS1390_TRICKLE_CHARGER_ENABLE;
	99	if (of_property_read_bool(spi->dev.of_node, "trickle-diode-disable"))
	100	value \|= DS1390_TRICKLE_CHARGER_NO_DIODE;
	101	else
	102	value \|= DS1390_TRICKLE_CHARGER_DIODE;
	103
	104	/* Resistor select */
	105	switch (ohms) {
	106	case 250:
	107	value \|= DS1390_TRICKLE_CHARGER_250_OHM;
	108	break;
	109	case 2000:
	110	value \|= DS1390_TRICKLE_CHARGER_2K_OHM;
	111	break;
	112	case 4000:
	113	value \|= DS1390_TRICKLE_CHARGER_4K_OHM;
	114	break;
	115	default:
	116	dev_warn(&spi->dev,
	117	"Unsupported ohm value %02ux in dt\n", ohms);
	118	return;
	119	}
	120
	121	ds1390_set_reg(&spi->dev, DS1390_REG_TRICKLE, value);
	122
	123	out:
	124	return;
	125	}
	126
7b9b2ef1	127	static int ds1390_read_time(struct device dev, struct rtc_time dt)
06de1808 MJ	128	{
	129	struct spi_device *spi = to_spi_device(dev);
	130	struct ds1390 *chip = dev_get_drvdata(dev);
	131	int status;
	132
	133	/* build the message */
	134	chip->txrx_buf[0] = DS1390_REG_SECONDS;
	135
	136	/* do the i/o */
	137	status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8);
	138	if (status != 0)
	139	return status;
	140
	141	/* The chip sends data in this order:
	142	* Seconds, Minutes, Hours, Day, Date, Month / Century, Year */
	143	dt->tm_sec = bcd2bin(chip->txrx_buf[0]);
	144	dt->tm_min = bcd2bin(chip->txrx_buf[1]);
	145	dt->tm_hour = bcd2bin(chip->txrx_buf[2]);
	146	dt->tm_wday = bcd2bin(chip->txrx_buf[3]);
	147	dt->tm_mday = bcd2bin(chip->txrx_buf[4]);
	148	/* mask off century bit */
	149	dt->tm_mon = bcd2bin(chip->txrx_buf[5] & 0x7f) - 1;
	150	/* adjust for century bit */
	151	dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0);
	152
22652ba7	153	return 0;
06de1808 MJ	154	}
06de1808 MJ	155
7b9b2ef1	156	static int ds1390_set_time(struct device dev, struct rtc_time dt)
06de1808 MJ	157	{
	158	struct spi_device *spi = to_spi_device(dev);
	159	struct ds1390 *chip = dev_get_drvdata(dev);
	160
	161	/* build the message */
	162	chip->txrx_buf[0] = DS1390_REG_SECONDS \| 0x80;
	163	chip->txrx_buf[1] = bin2bcd(dt->tm_sec);
	164	chip->txrx_buf[2] = bin2bcd(dt->tm_min);
	165	chip->txrx_buf[3] = bin2bcd(dt->tm_hour);
	166	chip->txrx_buf[4] = bin2bcd(dt->tm_wday);
	167	chip->txrx_buf[5] = bin2bcd(dt->tm_mday);
	168	chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) \|
	169	((dt->tm_year > 99) ? 0x80 : 0x00);
	170	chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100);
	171
	172	/* do the i/o */
	173	return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0);
	174	}
	175
06de1808 MJ	176	static const struct rtc_class_ops ds1390_rtc_ops = {
	177	.read_time = ds1390_read_time,
	178	.set_time = ds1390_set_time,
	179	};
	180
5a167f45	181	static int ds1390_probe(struct spi_device *spi)
06de1808	182	{
06de1808 MJ	183	unsigned char tmp;
	184	struct ds1390 *chip;
	185	int res;
	186
06de1808 MJ	187	spi->mode = SPI_MODE_3;
	188	spi->bits_per_word = 8;
	189	spi_setup(spi);
	190
1ce95ba7	191	chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL);
7841fe53	192	if (!chip)
06de1808	193	return -ENOMEM;
7841fe53	194
ccbc20f9	195	spi_set_drvdata(spi, chip);
06de1808 MJ	196
06de1808 MJ	197	res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp);
7b9b2ef1 AZ	198	if (res != 0) {
7b9b2ef1 AZ	199	dev_err(&spi->dev, "unable to read device\n");
06de1808 MJ	200	return res;
	201	}
	202
fa395fb8 IG	203	if (spi->dev.of_node)
	204	ds1390_trickle_of_init(spi);
	205
1ce95ba7 JH	206	chip->rtc = devm_rtc_device_register(&spi->dev, "ds1390",
1ce95ba7 JH	207	&ds1390_rtc_ops, THIS_MODULE);
7b9b2ef1 AZ	208	if (IS_ERR(chip->rtc)) {
	209	dev_err(&spi->dev, "unable to register device\n");
	210	res = PTR_ERR(chip->rtc);
7b9b2ef1 AZ	211	}
	212
	213	return res;
06de1808 MJ	214	}
06de1808 MJ	215
cca1e2f7	216	static const struct of_device_id ds1390_of_match[] __maybe_unused = {
3ba2c76a AB	217	{ .compatible = "dallas,ds1390" },
	218	{}
	219	};
	220	MODULE_DEVICE_TABLE(of, ds1390_of_match);
	221
da87639d MB	222	static const struct spi_device_id ds1390_spi_ids[] = {
	223	{ .name = "ds1390" },
	224	{}
	225	};
	226	MODULE_DEVICE_TABLE(spi, ds1390_spi_ids);
	227
06de1808 MJ	228	static struct spi_driver ds1390_driver = {
	229	.driver = {
	230	.name = "rtc-ds1390",
3ba2c76a	231	.of_match_table = of_match_ptr(ds1390_of_match),
06de1808 MJ	232	},
06de1808 MJ	233	.probe = ds1390_probe,
da87639d	234	.id_table = ds1390_spi_ids,
06de1808 MJ	235	};
06de1808 MJ	236
109e9418	237	module_spi_driver(ds1390_driver);
06de1808	238
7b9b2ef1	239	MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver");
06de1808 MJ	240	MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>");
06de1808 MJ	241	MODULE_LICENSE("GPL");
e0626e38	242	MODULE_ALIAS("spi:rtc-ds1390");