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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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.
 */

#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 0;
}

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

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
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
75b61022	2	/*
2805b969 MD	3	* Driver for Epson RTC-9701JE
	4	*
	5	* Copyright (C) 2008 Magnus Damm
	6	*
75b61022	7	* Based on rtc-max6902.c
2805b969 MD	8	*
	9	* Copyright (C) 2006 8D Technologies inc.
	10	* Copyright (C) 2004 Compulab Ltd.
2805b969 MD	11	*/
	12
	13	#include <linux/module.h>
2805b969 MD	14	#include <linux/kernel.h>
	15	#include <linux/platform_device.h>
	16	#include <linux/device.h>
	17	#include <linux/init.h>
	18	#include <linux/rtc.h>
	19	#include <linux/spi/spi.h>
	20	#include <linux/bcd.h>
	21	#include <linux/delay.h>
	22	#include <linux/bitops.h>
	23
	24	#define RSECCNT 0x00 /* Second Counter */
	25	#define RMINCNT 0x01 /* Minute Counter */
	26	#define RHRCNT 0x02 /* Hour Counter */
	27	#define RWKCNT 0x03 /* Week Counter */
	28	#define RDAYCNT 0x04 /* Day Counter */
	29	#define RMONCNT 0x05 /* Month Counter */
	30	#define RYRCNT 0x06 /* Year Counter */
	31	#define R100CNT 0x07 /* Y100 Counter */
	32	#define RMINAR 0x08 /* Minute Alarm */
	33	#define RHRAR 0x09 /* Hour Alarm */
	34	#define RWKAR 0x0a /* Week/Day Alarm */
	35	#define RTIMCNT 0x0c /* Interval Timer */
	36	#define REXT 0x0d /* Extension Register */
	37	#define RFLAG 0x0e /* RTC Flag Register */
	38	#define RCR 0x0f /* RTC Control Register */
	39
	40	static int write_reg(struct device *dev, int address, unsigned char data)
	41	{
	42	struct spi_device *spi = to_spi_device(dev);
	43	unsigned char buf[2];
	44
	45	buf[0] = address & 0x7f;
	46	buf[1] = data;
	47
	48	return spi_write(spi, buf, ARRAY_SIZE(buf));
	49	}
	50
	51	static int read_regs(struct device dev, unsigned char regs, int no_regs)
	52	{
	53	struct spi_device *spi = to_spi_device(dev);
	54	u8 txbuf[1], rxbuf[1];
	55	int k, ret;
	56
	57	ret = 0;
	58
	59	for (k = 0; ret == 0 && k < no_regs; k++) {
	60	txbuf[0] = 0x80 \| regs[k];
	61	ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1);
	62	regs[k] = rxbuf[0];
	63	}
	64
	65	return ret;
	66	}
	67
	68	static int r9701_get_datetime(struct device dev, struct rtc_time dt)
	69	{
2805b969 MD	70	int ret;
	71	unsigned char buf[] = { RSECCNT, RMINCNT, RHRCNT,
	72	RDAYCNT, RMONCNT, RYRCNT };
	73
75b61022	74	ret = read_regs(dev, buf, ARRAY_SIZE(buf));
2805b969 MD	75	if (ret)
	76	return ret;
	77
	78	memset(dt, 0, sizeof(*dt));
	79
fe20ba70 AB	80	dt->tm_sec = bcd2bin(buf[0]); /* RSECCNT */
	81	dt->tm_min = bcd2bin(buf[1]); /* RMINCNT */
	82	dt->tm_hour = bcd2bin(buf[2]); /* RHRCNT */
2805b969	83
fe20ba70 AB	84	dt->tm_mday = bcd2bin(buf[3]); /* RDAYCNT */
	85	dt->tm_mon = bcd2bin(buf[4]) - 1; /* RMONCNT */
	86	dt->tm_year = bcd2bin(buf[5]) + 100; /* RYRCNT */
2805b969 MD	87
	88	/* the rtc device may contain illegal values on power up
	89	* according to the data sheet. make sure they are valid.
	90	*/
	91
22652ba7	92	return 0;
2805b969 MD	93	}
	94
	95	static int r9701_set_datetime(struct device dev, struct rtc_time dt)
	96	{
	97	int ret, year;
	98
	99	year = dt->tm_year + 1900;
	100	if (year >= 2100 \|\| year < 2000)
	101	return -EINVAL;
	102
fe20ba70 AB	103	ret = write_reg(dev, RHRCNT, bin2bcd(dt->tm_hour));
	104	ret = ret ? ret : write_reg(dev, RMINCNT, bin2bcd(dt->tm_min));
	105	ret = ret ? ret : write_reg(dev, RSECCNT, bin2bcd(dt->tm_sec));
	106	ret = ret ? ret : write_reg(dev, RDAYCNT, bin2bcd(dt->tm_mday));
	107	ret = ret ? ret : write_reg(dev, RMONCNT, bin2bcd(dt->tm_mon + 1));
	108	ret = ret ? ret : write_reg(dev, RYRCNT, bin2bcd(dt->tm_year - 100));
75b61022	109	ret = ret ? ret : write_reg(dev, RWKCNT, 1 << dt->tm_wday);
2805b969 MD	110
	111	return ret;
	112	}
	113
	114	static const struct rtc_class_ops r9701_rtc_ops = {
	115	.read_time = r9701_get_datetime,
	116	.set_time = r9701_set_datetime,
	117	};
	118
5a167f45	119	static int r9701_probe(struct spi_device *spi)
2805b969 MD	120	{
2805b969 MD	121	struct rtc_device *rtc;
bb58da08	122	struct rtc_time dt;
2805b969 MD	123	unsigned char tmp;
	124	int res;
	125
73737b87 AG	126	tmp = R100CNT;
	127	res = read_regs(&spi->dev, &tmp, 1);
	128	if (res \|\| tmp != 0x20) {
	129	dev_err(&spi->dev, "cannot read RTC register\n");
	130	return -ENODEV;
	131	}
	132
bb58da08 AD	133	/*
	134	* The device seems to be present. Now check if the registers
	135	* contain invalid values. If so, try to write a default date:
	136	* 2000/1/1 00:00:00
	137	*/
aa11ec59	138	if (r9701_get_datetime(&spi->dev, &dt)) {
bb58da08 AD	139	dev_info(&spi->dev, "trying to repair invalid date/time\n");
	140	dt.tm_sec = 0;
	141	dt.tm_min = 0;
	142	dt.tm_hour = 0;
	143	dt.tm_mday = 1;
	144	dt.tm_mon = 0;
	145	dt.tm_year = 100;
	146
8e74b6ed AM	147	if (r9701_set_datetime(&spi->dev, &dt) \|\|
8e74b6ed AM	148	r9701_get_datetime(&spi->dev, &dt)) {
bb58da08 AD	149	dev_err(&spi->dev, "cannot repair RTC register\n");
	150	return -ENODEV;
	151	}
	152	}
	153
9b6d955a JH	154	rtc = devm_rtc_device_register(&spi->dev, "r9701",
9b6d955a JH	155	&r9701_rtc_ops, THIS_MODULE);
2805b969 MD	156	if (IS_ERR(rtc))
	157	return PTR_ERR(rtc);
	158
fbf52c0d	159	spi_set_drvdata(spi, rtc);
2805b969	160
2805b969 MD	161	return 0;
	162	}
	163
2805b969 MD	164	static struct spi_driver r9701_driver = {
	165	.driver = {
	166	.name = "rtc-r9701",
2805b969 MD	167	},
2805b969 MD	168	.probe = r9701_probe,
2805b969 MD	169	};
2805b969 MD	170
109e9418	171	module_spi_driver(r9701_driver);
2805b969 MD	172
	173	MODULE_DESCRIPTION("r9701 spi RTC driver");
	174	MODULE_AUTHOR("Magnus Damm <damm@opensource.se>");
	175	MODULE_LICENSE("GPL");
e0626e38	176	MODULE_ALIAS("spi:rtc-r9701");