[linux.git] / drivers / rtc / rtc-max6902.c

/* drivers/rtc/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.
 *
 * Driver for MAX6902 spi RTC
 *
 */

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

#define MAX6902_REG_SECONDS		0x01
#define MAX6902_REG_MINUTES		0x03
#define MAX6902_REG_HOURS		0x05
#define MAX6902_REG_DATE		0x07
#define MAX6902_REG_MONTH		0x09
#define MAX6902_REG_DAY			0x0B
#define MAX6902_REG_YEAR		0x0D
#define MAX6902_REG_CONTROL		0x0F
#define MAX6902_REG_CENTURY		0x13

static int max6902_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 '0' to write */
	buf[0] = address & 0x7f;
	buf[1] = data;

	return spi_write_then_read(spi, buf, 2, NULL, 0);
}

static int max6902_get_reg(struct device *dev, unsigned char address,
				unsigned char *data)
{
	struct spi_device *spi = to_spi_device(dev);

	/* Set MSB to indicate read */
	*data = address | 0x80;

	return spi_write_then_read(spi, data, 1, data, 1);
}

static int max6902_read_time(struct device *dev, struct rtc_time *dt)
{
	int err, century;
	struct spi_device *spi = to_spi_device(dev);
	unsigned char buf[8];

	buf[0] = 0xbf;	/* Burst read */

	err = spi_write_then_read(spi, buf, 1, buf, 8);
	if (err != 0)
		return err;

	/* The chip sends data in this order:
	 * Seconds, Minutes, Hours, Date, Month, Day, Year */
	dt->tm_sec	= bcd2bin(buf[0]);
	dt->tm_min	= bcd2bin(buf[1]);
	dt->tm_hour	= bcd2bin(buf[2]);
	dt->tm_mday	= bcd2bin(buf[3]);
	dt->tm_mon	= bcd2bin(buf[4]) - 1;
	dt->tm_wday	= bcd2bin(buf[5]);
	dt->tm_year	= bcd2bin(buf[6]);

	/* Read century */
	err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &buf[0]);
	if (err != 0)
		return err;

	century = bcd2bin(buf[0]) * 100;

	dt->tm_year += century;
	dt->tm_year -= 1900;

	return 0;
}

static int max6902_set_time(struct device *dev, struct rtc_time *dt)
{
	dt->tm_year = dt->tm_year + 1900;

	/* Remove write protection */
	max6902_set_reg(dev, MAX6902_REG_CONTROL, 0);

	max6902_set_reg(dev, MAX6902_REG_SECONDS, bin2bcd(dt->tm_sec));
	max6902_set_reg(dev, MAX6902_REG_MINUTES, bin2bcd(dt->tm_min));
	max6902_set_reg(dev, MAX6902_REG_HOURS, bin2bcd(dt->tm_hour));

	max6902_set_reg(dev, MAX6902_REG_DATE, bin2bcd(dt->tm_mday));
	max6902_set_reg(dev, MAX6902_REG_MONTH, bin2bcd(dt->tm_mon + 1));
	max6902_set_reg(dev, MAX6902_REG_DAY, bin2bcd(dt->tm_wday));
	max6902_set_reg(dev, MAX6902_REG_YEAR, bin2bcd(dt->tm_year % 100));
	max6902_set_reg(dev, MAX6902_REG_CENTURY, bin2bcd(dt->tm_year / 100));

	/* Compulab used a delay here. However, the datasheet
	 * does not mention a delay being required anywhere... */
	/* delay(2000); */

	/* Write protect */
	max6902_set_reg(dev, MAX6902_REG_CONTROL, 0x80);

	return 0;
}

static const struct rtc_class_ops max6902_rtc_ops = {
	.read_time	= max6902_read_time,
	.set_time	= max6902_set_time,
};

static int max6902_probe(struct spi_device *spi)
{
	struct rtc_device *rtc;
	unsigned char tmp;
	int res;

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

	res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp);
	if (res != 0)
		return res;

	rtc = devm_rtc_device_register(&spi->dev, "max6902",
				&max6902_rtc_ops, THIS_MODULE);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	spi_set_drvdata(spi, rtc);
	return 0;
}

static struct spi_driver max6902_driver = {
	.driver = {
		.name	= "rtc-max6902",
	},
	.probe	= max6902_probe,
};

module_spi_driver(max6902_driver);

MODULE_DESCRIPTION("max6902 spi RTC driver");
MODULE_AUTHOR("Raphael Assenat");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:rtc-max6902");
Commit	Line	Data
f30c2269	1	/* drivers/rtc/rtc-max6902.c
8e12ecc2 RA	2	*
	3	* Copyright (C) 2006 8D Technologies inc.
	4	* Copyright (C) 2004 Compulab Ltd.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* Driver for MAX6902 spi RTC
	11	*
8e12ecc2 RA	12	*/
8e12ecc2 RA	13
8e12ecc2	14	#include <linux/module.h>
8e12ecc2 RA	15	#include <linux/kernel.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/init.h>
	18	#include <linux/rtc.h>
	19	#include <linux/spi/spi.h>
	20	#include <linux/bcd.h>
8e12ecc2 RA	21
	22	#define MAX6902_REG_SECONDS 0x01
	23	#define MAX6902_REG_MINUTES 0x03
	24	#define MAX6902_REG_HOURS 0x05
	25	#define MAX6902_REG_DATE 0x07
	26	#define MAX6902_REG_MONTH 0x09
	27	#define MAX6902_REG_DAY 0x0B
	28	#define MAX6902_REG_YEAR 0x0D
	29	#define MAX6902_REG_CONTROL 0x0F
	30	#define MAX6902_REG_CENTURY 0x13
	31
a5771c6c	32	static int max6902_set_reg(struct device *dev, unsigned char address,
8e12ecc2 RA	33	unsigned char data)
	34	{
	35	struct spi_device *spi = to_spi_device(dev);
	36	unsigned char buf[2];
	37
	38	/* MSB must be '0' to write */
	39	buf[0] = address & 0x7f;
	40	buf[1] = data;
	41
a5771c6c	42	return spi_write_then_read(spi, buf, 2, NULL, 0);
8e12ecc2 RA	43	}
	44
	45	static int max6902_get_reg(struct device *dev, unsigned char address,
	46	unsigned char *data)
	47	{
	48	struct spi_device *spi = to_spi_device(dev);
8e12ecc2 RA	49
8e12ecc2 RA	50	/* Set MSB to indicate read */
a5771c6c	51	*data = address \| 0x80;
8e12ecc2	52
a5771c6c	53	return spi_write_then_read(spi, data, 1, data, 1);
8e12ecc2 RA	54	}
8e12ecc2 RA	55
a5771c6c	56	static int max6902_read_time(struct device dev, struct rtc_time dt)
8e12ecc2	57	{
a5771c6c	58	int err, century;
8e12ecc2	59	struct spi_device *spi = to_spi_device(dev);
a5771c6c	60	unsigned char buf[8];
8e12ecc2	61
a5771c6c	62	buf[0] = 0xbf; /* Burst read */
8e12ecc2	63
a5771c6c AZ	64	err = spi_write_then_read(spi, buf, 1, buf, 8);
	65	if (err != 0)
	66	return err;
8e12ecc2 RA	67
	68	/* The chip sends data in this order:
	69	* Seconds, Minutes, Hours, Date, Month, Day, Year */
a5771c6c AZ	70	dt->tm_sec = bcd2bin(buf[0]);
	71	dt->tm_min = bcd2bin(buf[1]);
	72	dt->tm_hour = bcd2bin(buf[2]);
	73	dt->tm_mday = bcd2bin(buf[3]);
	74	dt->tm_mon = bcd2bin(buf[4]) - 1;
	75	dt->tm_wday = bcd2bin(buf[5]);
	76	dt->tm_year = bcd2bin(buf[6]);
	77
	78	/* Read century */
	79	err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &buf[0]);
	80	if (err != 0)
	81	return err;
8e12ecc2	82
a5771c6c	83	century = bcd2bin(buf[0]) * 100;
8e12ecc2 RA	84
	85	dt->tm_year += century;
	86	dt->tm_year -= 1900;
	87
22652ba7	88	return 0;
8e12ecc2 RA	89	}
8e12ecc2 RA	90
a5771c6c	91	static int max6902_set_time(struct device dev, struct rtc_time dt)
8e12ecc2	92	{
a5771c6c	93	dt->tm_year = dt->tm_year + 1900;
8e12ecc2 RA	94
8e12ecc2 RA	95	/* Remove write protection */
08348d2f	96	max6902_set_reg(dev, MAX6902_REG_CONTROL, 0);
8e12ecc2	97
08348d2f AL	98	max6902_set_reg(dev, MAX6902_REG_SECONDS, bin2bcd(dt->tm_sec));
	99	max6902_set_reg(dev, MAX6902_REG_MINUTES, bin2bcd(dt->tm_min));
	100	max6902_set_reg(dev, MAX6902_REG_HOURS, bin2bcd(dt->tm_hour));
8e12ecc2	101
08348d2f AL	102	max6902_set_reg(dev, MAX6902_REG_DATE, bin2bcd(dt->tm_mday));
	103	max6902_set_reg(dev, MAX6902_REG_MONTH, bin2bcd(dt->tm_mon + 1));
	104	max6902_set_reg(dev, MAX6902_REG_DAY, bin2bcd(dt->tm_wday));
	105	max6902_set_reg(dev, MAX6902_REG_YEAR, bin2bcd(dt->tm_year % 100));
	106	max6902_set_reg(dev, MAX6902_REG_CENTURY, bin2bcd(dt->tm_year / 100));
8e12ecc2 RA	107
	108	/* Compulab used a delay here. However, the datasheet
	109	* does not mention a delay being required anywhere... */
	110	/* delay(2000); */
	111
	112	/* Write protect */
08348d2f	113	max6902_set_reg(dev, MAX6902_REG_CONTROL, 0x80);
8e12ecc2 RA	114
	115	return 0;
	116	}
	117
ff8371ac	118	static const struct rtc_class_ops max6902_rtc_ops = {
8e12ecc2 RA	119	.read_time = max6902_read_time,
	120	.set_time = max6902_set_time,
	121	};
	122
5a167f45	123	static int max6902_probe(struct spi_device *spi)
8e12ecc2 RA	124	{
	125	struct rtc_device *rtc;
	126	unsigned char tmp;
8e12ecc2 RA	127	int res;
8e12ecc2 RA	128
8e12ecc2 RA	129	spi->mode = SPI_MODE_3;
	130	spi->bits_per_word = 8;
	131	spi_setup(spi);
	132
8e12ecc2	133	res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp);
a5771c6c	134	if (res != 0)
8e12ecc2	135	return res;
a5771c6c	136
04353a73 JH	137	rtc = devm_rtc_device_register(&spi->dev, "max6902",
04353a73 JH	138	&max6902_rtc_ops, THIS_MODULE);
a5771c6c AZ	139	if (IS_ERR(rtc))
a5771c6c AZ	140	return PTR_ERR(rtc);
8e12ecc2	141
a5ef73f0	142	spi_set_drvdata(spi, rtc);
8e12ecc2 RA	143	return 0;
	144	}
	145
8e12ecc2 RA	146	static struct spi_driver max6902_driver = {
8e12ecc2 RA	147	.driver = {
5c076fce	148	.name = "rtc-max6902",
8e12ecc2	149	},
5c076fce	150	.probe = max6902_probe,
8e12ecc2 RA	151	};
8e12ecc2 RA	152
109e9418	153	module_spi_driver(max6902_driver);
8e12ecc2	154
83246a16 SK	155	MODULE_DESCRIPTION("max6902 spi RTC driver");
	156	MODULE_AUTHOR("Raphael Assenat");
	157	MODULE_LICENSE("GPL");
e0626e38	158	MODULE_ALIAS("spi:rtc-max6902");