[linux-2.6-block.git] / drivers / rtc / rtc-r9701.c

/*
 * Driver for Epson RTC-9701JE
 *
 * Copyright (C) 2008 Magnus Damm
 *
 * Based on rtc-max6902.c
 *
 * Copyright (C) 2006 8D Technologies inc.
 * Copyright (C) 2004 Compulab Ltd.
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/rtc.h>
#include <linux/spi/spi.h>
#include <linux/bcd.h>
#include <linux/delay.h>
#include <linux/bitops.h>

#define RSECCNT	0x00	/* Second Counter */
#define RMINCNT	0x01	/* Minute Counter */
#define RHRCNT	0x02	/* Hour Counter */
#define RWKCNT	0x03	/* Week Counter */
#define RDAYCNT	0x04	/* Day Counter */
#define RMONCNT	0x05	/* Month Counter */
#define RYRCNT	0x06	/* Year Counter */
#define R100CNT	0x07	/* Y100 Counter */
#define RMINAR	0x08	/* Minute Alarm */
#define RHRAR	0x09	/* Hour Alarm */
#define RWKAR	0x0a	/* Week/Day Alarm */
#define RTIMCNT	0x0c	/* Interval Timer */
#define REXT	0x0d	/* Extension Register */
#define RFLAG	0x0e	/* RTC Flag Register */
#define RCR	0x0f	/* RTC Control Register */

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

	buf[0] = address & 0x7f;
	buf[1] = data;

	return spi_write(spi, buf, ARRAY_SIZE(buf));
}

static int read_regs(struct device *dev, unsigned char *regs, int no_regs)
{
	struct spi_device *spi = to_spi_device(dev);
	u8 txbuf[1], rxbuf[1];
	int k, ret;

	ret = 0;

	for (k = 0; ret == 0 && k < no_regs; k++) {
		txbuf[0] = 0x80 | regs[k];
		ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
		regs[k] = rxbuf[0];
	}

	return ret;
}

static int r9701_get_datetime(struct device *dev, struct rtc_time *dt)
{
	int ret;
	unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT,
				RDAYCNT, RMONCNT, RYRCNT };

	ret = read_regs(dev, buf, ARRAY_SIZE(buf));
	if (ret)
		return ret;

	memset(dt, 0, sizeof(*dt));

	dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */
	dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */
	dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */

	dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */
	dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */
	dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */

	/* the rtc device may contain illegal values on power up
	 * according to the data sheet. make sure they are valid.
	 */

	return rtc_valid_tm(dt);
}

static int r9701_set_datetime(struct device *dev, struct rtc_time *dt)
{
	int ret, year;

	year = dt->tm_year + 1900;
	if (year >= 2100 || year < 2000)
		return -EINVAL;

	ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour));
	ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min));
	ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec));
	ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday));
	ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1));
	ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100));
	ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday);

	return ret;
}

static const struct rtc_class_ops r9701_rtc_ops = {
	.read_time	= r9701_get_datetime,
	.set_time	= r9701_set_datetime,
};

static int r9701_probe(struct spi_device *spi)
{
	struct rtc_device *rtc;
	struct rtc_time dt;
	unsigned char tmp;
	int res;

	tmp = R100CNT;
	res = read_regs(&spi->dev, &tmp, 1);
	if (res || tmp != 0x20) {
		dev_err(&spi->dev, "cannot read RTC register\n");
		return -ENODEV;
	}

	/*
	 * The device seems to be present. Now check if the registers
	 * contain invalid values. If so, try to write a default date:
	 * 2000/1/1 00:00:00
	 */
	if (r9701_get_datetime(&spi->dev, &dt)) {
		dev_info(&spi->dev, "trying to repair invalid date/time\n");
		dt.tm_sec  = 0;
		dt.tm_min  = 0;
		dt.tm_hour = 0;
		dt.tm_mday = 1;
		dt.tm_mon  = 0;
		dt.tm_year = 100;

		if (r9701_set_datetime(&spi->dev, &dt) ||
				r9701_get_datetime(&spi->dev, &dt)) {
			dev_err(&spi->dev, "cannot repair RTC register\n");
			return -ENODEV;
		}
	}

	rtc = devm_rtc_device_register(&spi->dev, "r9701",
				&r9701_rtc_ops, THIS_MODULE);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	spi_set_drvdata(spi, rtc);

	return 0;
}

static int r9701_remove(struct spi_device *spi)
{
	return 0;
}

static struct spi_driver r9701_driver = {
	.driver = {
		.name	= "rtc-r9701",
	},
	.probe	= r9701_probe,
	.remove = r9701_remove,
};

module_spi_driver(r9701_driver);

MODULE_DESCRIPTION("r9701 spi RTC driver");
MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:rtc-r9701");
Commit	Line	Data
75b61022	1	/*
2805b969 MD	2	* Driver for Epson RTC-9701JE
	3	*
	4	* Copyright (C) 2008 Magnus Damm
	5	*
75b61022	6	* Based on rtc-max6902.c
2805b969 MD	7	*
	8	* Copyright (C) 2006 8D Technologies inc.
	9	* Copyright (C) 2004 Compulab Ltd.
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License version 2 as
	13	* published by the Free Software Foundation.
	14	*/
	15
	16	#include <linux/module.h>
2805b969 MD	17	#include <linux/kernel.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/device.h>
	20	#include <linux/init.h>
	21	#include <linux/rtc.h>
	22	#include <linux/spi/spi.h>
	23	#include <linux/bcd.h>
	24	#include <linux/delay.h>
	25	#include <linux/bitops.h>
	26
	27	#define RSECCNT 0x00 /* Second Counter */
	28	#define RMINCNT 0x01 /* Minute Counter */
	29	#define RHRCNT 0x02 /* Hour Counter */
	30	#define RWKCNT 0x03 /* Week Counter */
	31	#define RDAYCNT 0x04 /* Day Counter */
	32	#define RMONCNT 0x05 /* Month Counter */
	33	#define RYRCNT 0x06 /* Year Counter */
	34	#define R100CNT 0x07 /* Y100 Counter */
	35	#define RMINAR 0x08 /* Minute Alarm */
	36	#define RHRAR 0x09 /* Hour Alarm */
	37	#define RWKAR 0x0a /* Week/Day Alarm */
	38	#define RTIMCNT 0x0c /* Interval Timer */
	39	#define REXT 0x0d /* Extension Register */
	40	#define RFLAG 0x0e /* RTC Flag Register */
	41	#define RCR 0x0f /* RTC Control Register */
	42
	43	static int write_reg(struct device *dev, int address, unsigned char data)
	44	{
	45	struct spi_device *spi = to_spi_device(dev);
	46	unsigned char buf[2];
	47
	48	buf[0] = address & 0x7f;
	49	buf[1] = data;
	50
	51	return spi_write(spi, buf, ARRAY_SIZE(buf));
	52	}
	53
	54	static int read_regs(struct device dev, unsigned char regs, int no_regs)
	55	{
	56	struct spi_device *spi = to_spi_device(dev);
	57	u8 txbuf[1], rxbuf[1];
	58	int k, ret;
	59
	60	ret = 0;
	61
	62	for (k = 0; ret == 0 && k < no_regs; k++) {
	63	txbuf[0] = 0x80 \| regs[k];
	64	ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
	65	regs[k] = rxbuf[0];
	66	}
	67
	68	return ret;
	69	}
	70
	71	static int r9701_get_datetime(struct device dev, struct rtc_time dt)
	72	{
2805b969 MD	73	int ret;
	74	unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT,
	75	RDAYCNT, RMONCNT, RYRCNT };
	76
75b61022	77	ret = read_regs(dev, buf, ARRAY_SIZE(buf));
2805b969 MD	78	if (ret)
	79	return ret;
	80
	81	memset(dt, 0, sizeof(*dt));
	82
fe20ba70 AB	83	dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */
	84	dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */
	85	dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */
2805b969	86
fe20ba70 AB	87	dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */
	88	dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */
	89	dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */
2805b969 MD	90
	91	/* the rtc device may contain illegal values on power up
	92	* according to the data sheet. make sure they are valid.
	93	*/
	94
75b61022	95	return rtc_valid_tm(dt);
2805b969 MD	96	}
	97
	98	static int r9701_set_datetime(struct device dev, struct rtc_time dt)
	99	{
	100	int ret, year;
	101
	102	year = dt->tm_year + 1900;
	103	if (year >= 2100 \|\| year < 2000)
	104	return -EINVAL;
	105
fe20ba70 AB	106	ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour));
	107	ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min));
	108	ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec));
	109	ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday));
	110	ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1));
	111	ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100));
75b61022	112	ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday);
2805b969 MD	113
	114	return ret;
	115	}
	116
	117	static const struct rtc_class_ops r9701_rtc_ops = {
	118	.read_time = r9701_get_datetime,
	119	.set_time = r9701_set_datetime,
	120	};
	121
5a167f45	122	static int r9701_probe(struct spi_device *spi)
2805b969 MD	123	{
2805b969 MD	124	struct rtc_device *rtc;
bb58da08	125	struct rtc_time dt;
2805b969 MD	126	unsigned char tmp;
	127	int res;
	128
73737b87 AG	129	tmp = R100CNT;
	130	res = read_regs(&spi->dev, &tmp, 1);
	131	if (res \|\| tmp != 0x20) {
	132	dev_err(&spi->dev, "cannot read RTC register\n");
	133	return -ENODEV;
	134	}
	135
bb58da08 AD	136	/*
	137	* The device seems to be present. Now check if the registers
	138	* contain invalid values. If so, try to write a default date:
	139	* 2000/1/1 00:00:00
	140	*/
aa11ec59	141	if (r9701_get_datetime(&spi->dev, &dt)) {
bb58da08 AD	142	dev_info(&spi->dev, "trying to repair invalid date/time\n");
	143	dt.tm_sec = 0;
	144	dt.tm_min = 0;
	145	dt.tm_hour = 0;
	146	dt.tm_mday = 1;
	147	dt.tm_mon = 0;
	148	dt.tm_year = 100;
	149
8e74b6ed AM	150	if (r9701_set_datetime(&spi->dev, &dt) \|\|
8e74b6ed AM	151	r9701_get_datetime(&spi->dev, &dt)) {
bb58da08 AD	152	dev_err(&spi->dev, "cannot repair RTC register\n");
	153	return -ENODEV;
	154	}
	155	}
	156
9b6d955a JH	157	rtc = devm_rtc_device_register(&spi->dev, "r9701",
9b6d955a JH	158	&r9701_rtc_ops, THIS_MODULE);
2805b969 MD	159	if (IS_ERR(rtc))
	160	return PTR_ERR(rtc);
	161
fbf52c0d	162	spi_set_drvdata(spi, rtc);
2805b969	163
2805b969 MD	164	return 0;
	165	}
	166
5a167f45	167	static int r9701_remove(struct spi_device *spi)
2805b969	168	{
2805b969 MD	169	return 0;
	170	}
	171
	172	static struct spi_driver r9701_driver = {
	173	.driver = {
	174	.name = "rtc-r9701",
2805b969 MD	175	},
2805b969 MD	176	.probe = r9701_probe,
5a167f45	177	.remove = r9701_remove,
2805b969 MD	178	};
2805b969 MD	179
109e9418	180	module_spi_driver(r9701_driver);
2805b969 MD	181
	182	MODULE_DESCRIPTION("r9701 spi RTC driver");
	183	MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
	184	MODULE_LICENSE("GPL");
e0626e38	185	MODULE_ALIAS("spi:rtc-r9701");