[deliverable/linux.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>

#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

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

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[1];

	return 0;
}

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

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

	chip = kzalloc(sizeof *chip, GFP_KERNEL);
	if (!chip) {
		dev_err(&spi->dev, "unable to allocate device memory\n");
		return -ENOMEM;
	}
	dev_set_drvdata(&spi->dev, chip);

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

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

	return res;
}

static int __devexit ds1390_remove(struct spi_device *spi)
{
	struct ds1390 *chip = platform_get_drvdata(spi);

	rtc_device_unregister(chip->rtc);
	kfree(chip);

	return 0;
}

static struct spi_driver ds1390_driver = {
	.driver = {
		.name	= "rtc-ds1390",
		.owner	= THIS_MODULE,
	},
	.probe	= ds1390_probe,
	.remove = __devexit_p(ds1390_remove),
};

static __init int ds1390_init(void)
{
	return spi_register_driver(&ds1390_driver);
}
module_init(ds1390_init);

static __exit void ds1390_exit(void)
{
	spi_unregister_driver(&ds1390_driver);
}
module_exit(ds1390_exit);

MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver");
MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>");
MODULE_LICENSE("GPL");
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>
	22
	23	#define DS1390_REG_100THS 0x00
	24	#define DS1390_REG_SECONDS 0x01
	25	#define DS1390_REG_MINUTES 0x02
	26	#define DS1390_REG_HOURS 0x03
	27	#define DS1390_REG_DAY 0x04
	28	#define DS1390_REG_DATE 0x05
	29	#define DS1390_REG_MONTH_CENT 0x06
	30	#define DS1390_REG_YEAR 0x07
	31
	32	#define DS1390_REG_ALARM_100THS 0x08
	33	#define DS1390_REG_ALARM_SECONDS 0x09
	34	#define DS1390_REG_ALARM_MINUTES 0x0A
	35	#define DS1390_REG_ALARM_HOURS 0x0B
	36	#define DS1390_REG_ALARM_DAY_DATE 0x0C
	37
	38	#define DS1390_REG_CONTROL 0x0D
	39	#define DS1390_REG_STATUS 0x0E
	40	#define DS1390_REG_TRICKLE 0x0F
	41
	42	struct ds1390 {
	43	struct rtc_device *rtc;
	44	u8 txrx_buf[9]; /* cmd + 8 registers */
	45	};
	46
06de1808 MJ	47	static int ds1390_get_reg(struct device *dev, unsigned char address,
	48	unsigned char *data)
	49	{
	50	struct spi_device *spi = to_spi_device(dev);
	51	struct ds1390 *chip = dev_get_drvdata(dev);
	52	int status;
	53
	54	if (!data)
	55	return -EINVAL;
	56
	57	/* Clear MSB to indicate read */
	58	chip->txrx_buf[0] = address & 0x7f;
	59	/* do the i/o */
	60	status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 1);
	61	if (status != 0)
	62	return status;
	63
	64	*data = chip->txrx_buf[1];
	65
	66	return 0;
	67	}
	68
7b9b2ef1	69	static int ds1390_read_time(struct device dev, struct rtc_time dt)
06de1808 MJ	70	{
	71	struct spi_device *spi = to_spi_device(dev);
	72	struct ds1390 *chip = dev_get_drvdata(dev);
	73	int status;
	74
	75	/* build the message */
	76	chip->txrx_buf[0] = DS1390_REG_SECONDS;
	77
	78	/* do the i/o */
	79	status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8);
	80	if (status != 0)
	81	return status;
	82
	83	/* The chip sends data in this order:
	84	* Seconds, Minutes, Hours, Day, Date, Month / Century, Year */
	85	dt->tm_sec = bcd2bin(chip->txrx_buf[0]);
	86	dt->tm_min = bcd2bin(chip->txrx_buf[1]);
	87	dt->tm_hour = bcd2bin(chip->txrx_buf[2]);
	88	dt->tm_wday = bcd2bin(chip->txrx_buf[3]);
	89	dt->tm_mday = bcd2bin(chip->txrx_buf[4]);
	90	/* mask off century bit */
	91	dt->tm_mon = bcd2bin(chip->txrx_buf[5] & 0x7f) - 1;
	92	/* adjust for century bit */
	93	dt->tm_year = bcd2bin(chip->txrx_buf[6]) + ((chip->txrx_buf[5] & 0x80) ? 100 : 0);
	94
	95	return rtc_valid_tm(dt);
	96	}
	97
7b9b2ef1	98	static int ds1390_set_time(struct device dev, struct rtc_time dt)
06de1808 MJ	99	{
	100	struct spi_device *spi = to_spi_device(dev);
	101	struct ds1390 *chip = dev_get_drvdata(dev);
	102
	103	/* build the message */
	104	chip->txrx_buf[0] = DS1390_REG_SECONDS \| 0x80;
	105	chip->txrx_buf[1] = bin2bcd(dt->tm_sec);
	106	chip->txrx_buf[2] = bin2bcd(dt->tm_min);
	107	chip->txrx_buf[3] = bin2bcd(dt->tm_hour);
	108	chip->txrx_buf[4] = bin2bcd(dt->tm_wday);
	109	chip->txrx_buf[5] = bin2bcd(dt->tm_mday);
	110	chip->txrx_buf[6] = bin2bcd(dt->tm_mon + 1) \|
	111	((dt->tm_year > 99) ? 0x80 : 0x00);
	112	chip->txrx_buf[7] = bin2bcd(dt->tm_year % 100);
	113
	114	/* do the i/o */
	115	return spi_write_then_read(spi, chip->txrx_buf, 8, NULL, 0);
	116	}
	117
06de1808 MJ	118	static const struct rtc_class_ops ds1390_rtc_ops = {
	119	.read_time = ds1390_read_time,
	120	.set_time = ds1390_set_time,
	121	};
	122
	123	static int __devinit ds1390_probe(struct spi_device *spi)
	124	{
	125	struct rtc_device *rtc;
	126	unsigned char tmp;
	127	struct ds1390 *chip;
	128	int res;
	129
06de1808 MJ	130	spi->mode = SPI_MODE_3;
	131	spi->bits_per_word = 8;
	132	spi_setup(spi);
	133
	134	chip = kzalloc(sizeof *chip, GFP_KERNEL);
	135	if (!chip) {
7b9b2ef1	136	dev_err(&spi->dev, "unable to allocate device memory\n");
06de1808 MJ	137	return -ENOMEM;
06de1808 MJ	138	}
06de1808 MJ	139	dev_set_drvdata(&spi->dev, chip);
	140
	141	res = ds1390_get_reg(&spi->dev, DS1390_REG_SECONDS, &tmp);
7b9b2ef1 AZ	142	if (res != 0) {
	143	dev_err(&spi->dev, "unable to read device\n");
	144	kfree(chip);
06de1808 MJ	145	return res;
	146	}
	147
7b9b2ef1 AZ	148	chip->rtc = rtc_device_register("ds1390",
	149	&spi->dev, &ds1390_rtc_ops, THIS_MODULE);
	150	if (IS_ERR(chip->rtc)) {
	151	dev_err(&spi->dev, "unable to register device\n");
	152	res = PTR_ERR(chip->rtc);
	153	kfree(chip);
	154	}
	155
	156	return res;
06de1808 MJ	157	}
	158
	159	static int __devexit ds1390_remove(struct spi_device *spi)
	160	{
	161	struct ds1390 *chip = platform_get_drvdata(spi);
06de1808	162
7b9b2ef1	163	rtc_device_unregister(chip->rtc);
06de1808 MJ	164	kfree(chip);
	165
	166	return 0;
	167	}
	168
	169	static struct spi_driver ds1390_driver = {
	170	.driver = {
	171	.name = "rtc-ds1390",
	172	.owner = THIS_MODULE,
	173	},
	174	.probe = ds1390_probe,
	175	.remove = __devexit_p(ds1390_remove),
	176	};
	177
	178	static __init int ds1390_init(void)
	179	{
	180	return spi_register_driver(&ds1390_driver);
	181	}
	182	module_init(ds1390_init);
	183
	184	static __exit void ds1390_exit(void)
	185	{
	186	spi_unregister_driver(&ds1390_driver);
	187	}
	188	module_exit(ds1390_exit);
	189
7b9b2ef1	190	MODULE_DESCRIPTION("Dallas/Maxim DS1390/93/94 SPI RTC driver");
06de1808 MJ	191	MODULE_AUTHOR("Mark Jackson <mpfj@mimc.co.uk>");
06de1808 MJ	192	MODULE_LICENSE("GPL");