[linux-2.6-block.git] / drivers / rtc / rtc-ds1390.c

/*
 * 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>
 *
 * 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.
 *
 * 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 rtc_valid_tm(dt);
}

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 struct spi_driver ds1390_driver = {
	.driver = {
		.name	= "rtc-ds1390",
	},
	.probe	= ds1390_probe,
};

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