[deliverable/linux.git] / drivers / rtc / rtc-ds1307.c

/*
 * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
 *
 *  Copyright (C) 2005 James Chapman (ds1337 core)
 *  Copyright (C) 2006 David Brownell
 *
 * 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/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/rtc.h>
#include <linux/bcd.h>


/* We can't determine type by probing, but if we expect pre-Linux code
 * to have set the chip up as a clock (turning on the oscillator and
 * setting the date and time), Linux can ignore the non-clock features.
 * That's a natural job for a factory or repair bench.
 *
 * This is currently a simple no-alarms driver.  If your board has the
 * alarm irq wired up on a ds1337 or ds1339, and you want to use that,
 * then look at the rtc-rs5c372 driver for code to steal...
 */
enum ds_type {
	ds_1307,
	ds_1337,
	ds_1338,
	ds_1339,
	ds_1340,
	m41t00,
	// rs5c372 too?  different address...
};


/* RTC registers don't differ much, except for the century flag */
#define DS1307_REG_SECS		0x00	/* 00-59 */
#	define DS1307_BIT_CH		0x80
#	define DS1340_BIT_nEOSC		0x80
#define DS1307_REG_MIN		0x01	/* 00-59 */
#define DS1307_REG_HOUR		0x02	/* 00-23, or 1-12{am,pm} */
#	define DS1307_BIT_12HR		0x40	/* in REG_HOUR */
#	define DS1307_BIT_PM		0x20	/* in REG_HOUR */
#	define DS1340_BIT_CENTURY_EN	0x80	/* in REG_HOUR */
#	define DS1340_BIT_CENTURY	0x40	/* in REG_HOUR */
#define DS1307_REG_WDAY		0x03	/* 01-07 */
#define DS1307_REG_MDAY		0x04	/* 01-31 */
#define DS1307_REG_MONTH	0x05	/* 01-12 */
#	define DS1337_BIT_CENTURY	0x80	/* in REG_MONTH */
#define DS1307_REG_YEAR		0x06	/* 00-99 */

/* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
 * start at 7, and they differ a LOT. Only control and status matter for
 * basic RTC date and time functionality; be careful using them.
 */
#define DS1307_REG_CONTROL	0x07		/* or ds1338 */
#	define DS1307_BIT_OUT		0x80
#	define DS1338_BIT_OSF		0x20
#	define DS1307_BIT_SQWE		0x10
#	define DS1307_BIT_RS1		0x02
#	define DS1307_BIT_RS0		0x01
#define DS1337_REG_CONTROL	0x0e
#	define DS1337_BIT_nEOSC		0x80
#	define DS1337_BIT_RS2		0x10
#	define DS1337_BIT_RS1		0x08
#	define DS1337_BIT_INTCN		0x04
#	define DS1337_BIT_A2IE		0x02
#	define DS1337_BIT_A1IE		0x01
#define DS1340_REG_CONTROL	0x07
#	define DS1340_BIT_OUT		0x80
#	define DS1340_BIT_FT		0x40
#	define DS1340_BIT_CALIB_SIGN	0x20
#	define DS1340_M_CALIBRATION	0x1f
#define DS1340_REG_FLAG		0x09
#	define DS1340_BIT_OSF		0x80
#define DS1337_REG_STATUS	0x0f
#	define DS1337_BIT_OSF		0x80
#	define DS1337_BIT_A2I		0x02
#	define DS1337_BIT_A1I		0x01
#define DS1339_REG_TRICKLE	0x10


struct ds1307 {
	u8			reg_addr;
	bool			has_nvram;
	u8			regs[8];
	enum ds_type		type;
	struct i2c_msg		msg[2];
	struct i2c_client	*client;
	struct i2c_client	dev;
	struct rtc_device	*rtc;
};

struct chip_desc {
	char			name[9];
	unsigned		nvram56:1;
	unsigned		alarm:1;
	enum ds_type		type;
};

static const struct chip_desc chips[] = { {
	.name		= "ds1307",
	.type		= ds_1307,
	.nvram56	= 1,
}, {
	.name		= "ds1337",
	.type		= ds_1337,
	.alarm		= 1,
}, {
	.name		= "ds1338",
	.type		= ds_1338,
	.nvram56	= 1,
}, {
	.name		= "ds1339",
	.type		= ds_1339,
	.alarm		= 1,
}, {
	.name		= "ds1340",
	.type		= ds_1340,
}, {
	.name		= "m41t00",
	.type		= m41t00,
}, };

static inline const struct chip_desc *find_chip(const char *s)
{
	unsigned i;

	for (i = 0; i < ARRAY_SIZE(chips); i++)
		if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0)
			return &chips[i];
	return NULL;
}

static int ds1307_get_time(struct device *dev, struct rtc_time *t)
{
	struct ds1307	*ds1307 = dev_get_drvdata(dev);
	int		tmp;

	/* read the RTC date and time registers all at once */
	ds1307->msg[1].flags = I2C_M_RD;
	ds1307->msg[1].len = 7;

	tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
			ds1307->msg, 2);
	if (tmp != 2) {
		dev_err(dev, "%s error %d\n", "read", tmp);
		return -EIO;
	}

	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
			"read",
			ds1307->regs[0], ds1307->regs[1],
			ds1307->regs[2], ds1307->regs[3],
			ds1307->regs[4], ds1307->regs[5],
			ds1307->regs[6]);

	t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f);
	t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
	tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
	t->tm_hour = BCD2BIN(tmp);
	t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
	t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
	tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
	t->tm_mon = BCD2BIN(tmp) - 1;

	/* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
	t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100;

	dev_dbg(dev, "%s secs=%d, mins=%d, "
		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
		"read", t->tm_sec, t->tm_min,
		t->tm_hour, t->tm_mday,
		t->tm_mon, t->tm_year, t->tm_wday);

	/* initial clock setting can be undefined */
	return rtc_valid_tm(t);
}

static int ds1307_set_time(struct device *dev, struct rtc_time *t)
{
	struct ds1307	*ds1307 = dev_get_drvdata(dev);
	int		result;
	int		tmp;
	u8		*buf = ds1307->regs;

	dev_dbg(dev, "%s secs=%d, mins=%d, "
		"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
		"write", t->tm_sec, t->tm_min,
		t->tm_hour, t->tm_mday,
		t->tm_mon, t->tm_year, t->tm_wday);

	*buf++ = 0;		/* first register addr */
	buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec);
	buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min);
	buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour);
	buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1);
	buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday);
	buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1);

	/* assume 20YY not 19YY */
	tmp = t->tm_year - 100;
	buf[DS1307_REG_YEAR] = BIN2BCD(tmp);

	switch (ds1307->type) {
	case ds_1337:
	case ds_1339:
		buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
		break;
	case ds_1340:
		buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
				| DS1340_BIT_CENTURY;
		break;
	default:
		break;
	}

	ds1307->msg[1].flags = 0;
	ds1307->msg[1].len = 8;

	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
		"write", buf[0], buf[1], buf[2], buf[3],
		buf[4], buf[5], buf[6]);

	result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
			&ds1307->msg[1], 1);
	if (result != 1) {
		dev_err(dev, "%s error %d\n", "write", tmp);
		return -EIO;
	}
	return 0;
}

static const struct rtc_class_ops ds13xx_rtc_ops = {
	.read_time	= ds1307_get_time,
	.set_time	= ds1307_set_time,
};

/*----------------------------------------------------------------------*/

#define NVRAM_SIZE	56

static ssize_t
ds1307_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
		char *buf, loff_t off, size_t count)
{
	struct i2c_client	*client;
	struct ds1307		*ds1307;
	struct i2c_msg		msg[2];
	int			result;

	client = to_i2c_client(container_of(kobj, struct device, kobj));
	ds1307 = i2c_get_clientdata(client);

	if (unlikely(off >= NVRAM_SIZE))
		return 0;
	if ((off + count) > NVRAM_SIZE)
		count = NVRAM_SIZE - off;
	if (unlikely(!count))
		return count;

	msg[0].addr = client->addr;
	msg[0].flags = 0;
	msg[0].len = 1;
	msg[0].buf = buf;

	buf[0] = 8 + off;

	msg[1].addr = client->addr;
	msg[1].flags = I2C_M_RD;
	msg[1].len = count;
	msg[1].buf = buf;

	result = i2c_transfer(to_i2c_adapter(client->dev.parent), msg, 2);
	if (result != 2) {
		dev_err(&client->dev, "%s error %d\n", "nvram read", result);
		return -EIO;
	}
	return count;
}

static ssize_t
ds1307_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
		char *buf, loff_t off, size_t count)
{
	struct i2c_client	*client;
	u8			buffer[NVRAM_SIZE + 1];
	int			ret;

	client = to_i2c_client(container_of(kobj, struct device, kobj));

	if (unlikely(off >= NVRAM_SIZE))
		return -EFBIG;
	if ((off + count) > NVRAM_SIZE)
		count = NVRAM_SIZE - off;
	if (unlikely(!count))
		return count;

	buffer[0] = 8 + off;
	memcpy(buffer + 1, buf, count);

	ret = i2c_master_send(client, buffer, count + 1);
	return (ret < 0) ? ret : (ret - 1);
}

static struct bin_attribute nvram = {
	.attr = {
		.name	= "nvram",
		.mode	= S_IRUGO | S_IWUSR,
		.owner	= THIS_MODULE,
	},

	.read	= ds1307_nvram_read,
	.write	= ds1307_nvram_write,
	.size	= NVRAM_SIZE,
};

/*----------------------------------------------------------------------*/

static struct i2c_driver ds1307_driver;

static int __devinit ds1307_probe(struct i2c_client *client)
{
	struct ds1307		*ds1307;
	int			err = -ENODEV;
	int			tmp;
	const struct chip_desc	*chip;
	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);

	chip = find_chip(client->name);
	if (!chip) {
		dev_err(&client->dev, "unknown chip type '%s'\n",
				client->name);
		return -ENODEV;
	}

	if (!i2c_check_functionality(adapter,
			I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
		return -EIO;

	if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
		return -ENOMEM;

	ds1307->client = client;
	i2c_set_clientdata(client, ds1307);

	ds1307->msg[0].addr = client->addr;
	ds1307->msg[0].flags = 0;
	ds1307->msg[0].len = 1;
	ds1307->msg[0].buf = &ds1307->reg_addr;

	ds1307->msg[1].addr = client->addr;
	ds1307->msg[1].flags = I2C_M_RD;
	ds1307->msg[1].len = sizeof(ds1307->regs);
	ds1307->msg[1].buf = ds1307->regs;

	ds1307->type = chip->type;

	switch (ds1307->type) {
	case ds_1337:
	case ds_1339:
		ds1307->reg_addr = DS1337_REG_CONTROL;
		ds1307->msg[1].len = 2;

		/* get registers that the "rtc" read below won't read... */
		tmp = i2c_transfer(adapter, ds1307->msg, 2);
		if (tmp != 2) {
			pr_debug("read error %d\n", tmp);
			err = -EIO;
			goto exit_free;
		}

		ds1307->reg_addr = 0;
		ds1307->msg[1].len = sizeof(ds1307->regs);

		/* oscillator off?  turn it on, so clock can tick. */
		if (ds1307->regs[0] & DS1337_BIT_nEOSC)
			i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
				ds1307->regs[0] & ~DS1337_BIT_nEOSC);

		/* oscillator fault?  clear flag, and warn */
		if (ds1307->regs[1] & DS1337_BIT_OSF) {
			i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
				ds1307->regs[1] & ~DS1337_BIT_OSF);
			dev_warn(&client->dev, "SET TIME!\n");
		}
		break;
	default:
		break;
	}

read_rtc:
	/* read RTC registers */

	tmp = i2c_transfer(adapter, ds1307->msg, 2);
	if (tmp != 2) {
		pr_debug("read error %d\n", tmp);
		err = -EIO;
		goto exit_free;
	}

	/* minimal sanity checking; some chips (like DS1340) don't
	 * specify the extra bits as must-be-zero, but there are
	 * still a few values that are clearly out-of-range.
	 */
	tmp = ds1307->regs[DS1307_REG_SECS];
	switch (ds1307->type) {
	case ds_1340:
		/* FIXME read register with DS1340_BIT_OSF, use that to
		 * trigger the "set time" warning (*after* restarting the
		 * oscillator!) instead of this weaker ds1307/m41t00 test.
		 */
	case ds_1307:
	case m41t00:
		/* clock halted?  turn it on, so clock can tick. */
		if (tmp & DS1307_BIT_CH) {
			i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
			dev_warn(&client->dev, "SET TIME!\n");
			goto read_rtc;
		}
		break;
	case ds_1338:
		/* clock halted?  turn it on, so clock can tick. */
		if (tmp & DS1307_BIT_CH)
			i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);

		/* oscillator fault?  clear flag, and warn */
		if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
			i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
					ds1307->regs[DS1307_REG_CONTROL]
					& ~DS1338_BIT_OSF);
			dev_warn(&client->dev, "SET TIME!\n");
			goto read_rtc;
		}
		break;
	case ds_1337:
	case ds_1339:
		break;
	}

	tmp = ds1307->regs[DS1307_REG_SECS];
	tmp = BCD2BIN(tmp & 0x7f);
	if (tmp > 60)
		goto exit_bad;
	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
	if (tmp > 60)
		goto exit_bad;

	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
	if (tmp == 0 || tmp > 31)
		goto exit_bad;

	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
	if (tmp == 0 || tmp > 12)
		goto exit_bad;

	tmp = ds1307->regs[DS1307_REG_HOUR];
	switch (ds1307->type) {
	case ds_1340:
	case m41t00:
		/* NOTE: ignores century bits; fix before deploying
		 * systems that will run through year 2100.
		 */
		break;
	default:
		if (!(tmp & DS1307_BIT_12HR))
			break;

		/* Be sure we're in 24 hour mode.  Multi-master systems
		 * take note...
		 */
		tmp = BCD2BIN(tmp & 0x1f);
		if (tmp == 12)
			tmp = 0;
		if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
			tmp += 12;
		i2c_smbus_write_byte_data(client,
				DS1307_REG_HOUR,
				BIN2BCD(tmp));
	}

	ds1307->rtc = rtc_device_register(client->name, &client->dev,
				&ds13xx_rtc_ops, THIS_MODULE);
	if (IS_ERR(ds1307->rtc)) {
		err = PTR_ERR(ds1307->rtc);
		dev_err(&client->dev,
			"unable to register the class device\n");
		goto exit_free;
	}

	if (chip->nvram56) {
		err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
		if (err == 0) {
			ds1307->has_nvram = true;
			dev_info(&client->dev, "56 bytes nvram\n");
		}
	}

	return 0;

exit_bad:
	dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
			"bogus register",
			ds1307->regs[0], ds1307->regs[1],
			ds1307->regs[2], ds1307->regs[3],
			ds1307->regs[4], ds1307->regs[5],
			ds1307->regs[6]);

exit_free:
	kfree(ds1307);
	return err;
}

static int __devexit ds1307_remove(struct i2c_client *client)
{
	struct ds1307	*ds1307 = i2c_get_clientdata(client);

	if (ds1307->has_nvram)
		sysfs_remove_bin_file(&client->dev.kobj, &nvram);

	rtc_device_unregister(ds1307->rtc);
	kfree(ds1307);
	return 0;
}

static struct i2c_driver ds1307_driver = {
	.driver = {
		.name	= "rtc-ds1307",
		.owner	= THIS_MODULE,
	},
	.probe		= ds1307_probe,
	.remove		= __devexit_p(ds1307_remove),
};

static int __init ds1307_init(void)
{
	return i2c_add_driver(&ds1307_driver);
}
module_init(ds1307_init);

static void __exit ds1307_exit(void)
{
	i2c_del_driver(&ds1307_driver);
}
module_exit(ds1307_exit);

MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
MODULE_LICENSE("GPL");
Commit	Line	Data
1abb0dc9 DB	1	/*
	2	* rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
	3	*
	4	* Copyright (C) 2005 James Chapman (ds1337 core)
	5	* Copyright (C) 2006 David Brownell
	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	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/init.h>
	14	#include <linux/slab.h>
	15	#include <linux/i2c.h>
	16	#include <linux/string.h>
	17	#include <linux/rtc.h>
	18	#include <linux/bcd.h>
	19
	20
	21
	22	/* We can't determine type by probing, but if we expect pre-Linux code
	23	* to have set the chip up as a clock (turning on the oscillator and
	24	* setting the date and time), Linux can ignore the non-clock features.
	25	* That's a natural job for a factory or repair bench.
	26	*
045e0e85 DB	27	* This is currently a simple no-alarms driver. If your board has the
	28	* alarm irq wired up on a ds1337 or ds1339, and you want to use that,
	29	* then look at the rtc-rs5c372 driver for code to steal...
1abb0dc9 DB	30	*/
1abb0dc9 DB	31	enum ds_type {
045e0e85 DB	32	ds_1307,
	33	ds_1337,
	34	ds_1338,
	35	ds_1339,
	36	ds_1340,
	37	m41t00,
1abb0dc9 DB	38	// rs5c372 too? different address...
	39	};
	40
1abb0dc9 DB	41
	42	/* RTC registers don't differ much, except for the century flag */
	43	#define DS1307_REG_SECS 0x00 /* 00-59 */
	44	# define DS1307_BIT_CH 0x80
be5f59f4	45	# define DS1340_BIT_nEOSC 0x80
1abb0dc9 DB	46	#define DS1307_REG_MIN 0x01 /* 00-59 */
1abb0dc9 DB	47	#define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */
c065f35c DB	48	# define DS1307_BIT_12HR 0x40 /* in REG_HOUR */
c065f35c DB	49	# define DS1307_BIT_PM 0x20 /* in REG_HOUR */
1abb0dc9 DB	50	# define DS1340_BIT_CENTURY_EN 0x80 /* in REG_HOUR */
	51	# define DS1340_BIT_CENTURY 0x40 /* in REG_HOUR */
	52	#define DS1307_REG_WDAY 0x03 /* 01-07 */
	53	#define DS1307_REG_MDAY 0x04 /* 01-31 */
	54	#define DS1307_REG_MONTH 0x05 /* 01-12 */
	55	# define DS1337_BIT_CENTURY 0x80 /* in REG_MONTH */
	56	#define DS1307_REG_YEAR 0x06 /* 00-99 */
	57
	58	/* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
045e0e85 DB	59	* start at 7, and they differ a LOT. Only control and status matter for
045e0e85 DB	60	* basic RTC date and time functionality; be careful using them.
1abb0dc9	61	*/
045e0e85	62	#define DS1307_REG_CONTROL 0x07 /* or ds1338 */
1abb0dc9	63	# define DS1307_BIT_OUT 0x80
be5f59f4	64	# define DS1338_BIT_OSF 0x20
1abb0dc9 DB	65	# define DS1307_BIT_SQWE 0x10
	66	# define DS1307_BIT_RS1 0x02
	67	# define DS1307_BIT_RS0 0x01
	68	#define DS1337_REG_CONTROL 0x0e
	69	# define DS1337_BIT_nEOSC 0x80
	70	# define DS1337_BIT_RS2 0x10
	71	# define DS1337_BIT_RS1 0x08
	72	# define DS1337_BIT_INTCN 0x04
	73	# define DS1337_BIT_A2IE 0x02
	74	# define DS1337_BIT_A1IE 0x01
045e0e85 DB	75	#define DS1340_REG_CONTROL 0x07
	76	# define DS1340_BIT_OUT 0x80
	77	# define DS1340_BIT_FT 0x40
	78	# define DS1340_BIT_CALIB_SIGN 0x20
	79	# define DS1340_M_CALIBRATION 0x1f
be5f59f4 RG	80	#define DS1340_REG_FLAG 0x09
be5f59f4 RG	81	# define DS1340_BIT_OSF 0x80
1abb0dc9 DB	82	#define DS1337_REG_STATUS 0x0f
	83	# define DS1337_BIT_OSF 0x80
	84	# define DS1337_BIT_A2I 0x02
	85	# define DS1337_BIT_A1I 0x01
	86	#define DS1339_REG_TRICKLE 0x10
	87
	88
	89
	90	struct ds1307 {
	91	u8 reg_addr;
682d73f6	92	bool has_nvram;
1abb0dc9 DB	93	u8 regs[8];
	94	enum ds_type type;
	95	struct i2c_msg msg[2];
045e0e85 DB	96	struct i2c_client *client;
045e0e85 DB	97	struct i2c_client dev;
1abb0dc9 DB	98	struct rtc_device *rtc;
	99	};
	100
045e0e85 DB	101	struct chip_desc {
	102	char name[9];
	103	unsigned nvram56:1;
	104	unsigned alarm:1;
	105	enum ds_type type;
	106	};
	107
	108	static const struct chip_desc chips[] = { {
	109	.name = "ds1307",
	110	.type = ds_1307,
	111	.nvram56 = 1,
	112	}, {
	113	.name = "ds1337",
	114	.type = ds_1337,
	115	.alarm = 1,
	116	}, {
	117	.name = "ds1338",
	118	.type = ds_1338,
	119	.nvram56 = 1,
	120	}, {
	121	.name = "ds1339",
	122	.type = ds_1339,
	123	.alarm = 1,
	124	}, {
	125	.name = "ds1340",
	126	.type = ds_1340,
	127	}, {
	128	.name = "m41t00",
	129	.type = m41t00,
	130	}, };
	131
	132	static inline const struct chip_desc find_chip(const char s)
	133	{
	134	unsigned i;
	135
	136	for (i = 0; i < ARRAY_SIZE(chips); i++)
	137	if (strnicmp(s, chips[i].name, sizeof chips[i].name) == 0)
	138	return &chips[i];
	139	return NULL;
	140	}
1abb0dc9 DB	141
	142	static int ds1307_get_time(struct device dev, struct rtc_time t)
	143	{
	144	struct ds1307 *ds1307 = dev_get_drvdata(dev);
	145	int tmp;
	146
045e0e85	147	/* read the RTC date and time registers all at once */
1abb0dc9 DB	148	ds1307->msg[1].flags = I2C_M_RD;
	149	ds1307->msg[1].len = 7;
	150
045e0e85 DB	151	tmp = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
045e0e85 DB	152	ds1307->msg, 2);
1abb0dc9 DB	153	if (tmp != 2) {
	154	dev_err(dev, "%s error %d\n", "read", tmp);
	155	return -EIO;
	156	}
	157
	158	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
	159	"read",
	160	ds1307->regs[0], ds1307->regs[1],
	161	ds1307->regs[2], ds1307->regs[3],
	162	ds1307->regs[4], ds1307->regs[5],
	163	ds1307->regs[6]);
	164
	165	t->tm_sec = BCD2BIN(ds1307->regs[DS1307_REG_SECS] & 0x7f);
	166	t->tm_min = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
	167	tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
	168	t->tm_hour = BCD2BIN(tmp);
	169	t->tm_wday = BCD2BIN(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
	170	t->tm_mday = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
	171	tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
	172	t->tm_mon = BCD2BIN(tmp) - 1;
	173
	174	/* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
	175	t->tm_year = BCD2BIN(ds1307->regs[DS1307_REG_YEAR]) + 100;
	176
	177	dev_dbg(dev, "%s secs=%d, mins=%d, "
	178	"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
	179	"read", t->tm_sec, t->tm_min,
	180	t->tm_hour, t->tm_mday,
	181	t->tm_mon, t->tm_year, t->tm_wday);
	182
045e0e85 DB	183	/* initial clock setting can be undefined */
045e0e85 DB	184	return rtc_valid_tm(t);
1abb0dc9 DB	185	}
	186
	187	static int ds1307_set_time(struct device dev, struct rtc_time t)
	188	{
	189	struct ds1307 *ds1307 = dev_get_drvdata(dev);
	190	int result;
	191	int tmp;
	192	u8 *buf = ds1307->regs;
	193
	194	dev_dbg(dev, "%s secs=%d, mins=%d, "
	195	"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
11966adc JG	196	"write", t->tm_sec, t->tm_min,
	197	t->tm_hour, t->tm_mday,
	198	t->tm_mon, t->tm_year, t->tm_wday);
1abb0dc9 DB	199
	200	buf++ = 0; / first register addr */
	201	buf[DS1307_REG_SECS] = BIN2BCD(t->tm_sec);
	202	buf[DS1307_REG_MIN] = BIN2BCD(t->tm_min);
	203	buf[DS1307_REG_HOUR] = BIN2BCD(t->tm_hour);
	204	buf[DS1307_REG_WDAY] = BIN2BCD(t->tm_wday + 1);
	205	buf[DS1307_REG_MDAY] = BIN2BCD(t->tm_mday);
	206	buf[DS1307_REG_MONTH] = BIN2BCD(t->tm_mon + 1);
	207
	208	/* assume 20YY not 19YY */
	209	tmp = t->tm_year - 100;
	210	buf[DS1307_REG_YEAR] = BIN2BCD(tmp);
	211
be5f59f4 RG	212	switch (ds1307->type) {
	213	case ds_1337:
	214	case ds_1339:
1abb0dc9	215	buf[DS1307_REG_MONTH] \|= DS1337_BIT_CENTURY;
be5f59f4 RG	216	break;
be5f59f4 RG	217	case ds_1340:
1abb0dc9 DB	218	buf[DS1307_REG_HOUR] \|= DS1340_BIT_CENTURY_EN
1abb0dc9 DB	219	\| DS1340_BIT_CENTURY;
be5f59f4 RG	220	break;
	221	default:
	222	break;
	223	}
1abb0dc9 DB	224
	225	ds1307->msg[1].flags = 0;
	226	ds1307->msg[1].len = 8;
	227
	228	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
	229	"write", buf[0], buf[1], buf[2], buf[3],
	230	buf[4], buf[5], buf[6]);
	231
045e0e85 DB	232	result = i2c_transfer(to_i2c_adapter(ds1307->client->dev.parent),
045e0e85 DB	233	&ds1307->msg[1], 1);
1abb0dc9 DB	234	if (result != 1) {
	235	dev_err(dev, "%s error %d\n", "write", tmp);
	236	return -EIO;
	237	}
	238	return 0;
	239	}
	240
ff8371ac	241	static const struct rtc_class_ops ds13xx_rtc_ops = {
1abb0dc9 DB	242	.read_time = ds1307_get_time,
	243	.set_time = ds1307_set_time,
	244	};
	245
682d73f6 DB	246	/----------------------------------------------------------------------/
	247
	248	#define NVRAM_SIZE 56
	249
	250	static ssize_t
	251	ds1307_nvram_read(struct kobject kobj, struct bin_attribute attr,
	252	char *buf, loff_t off, size_t count)
	253	{
	254	struct i2c_client *client;
	255	struct ds1307 *ds1307;
	256	struct i2c_msg msg[2];
	257	int result;
	258
	259	client = to_i2c_client(container_of(kobj, struct device, kobj));
	260	ds1307 = i2c_get_clientdata(client);
	261
	262	if (unlikely(off >= NVRAM_SIZE))
	263	return 0;
	264	if ((off + count) > NVRAM_SIZE)
	265	count = NVRAM_SIZE - off;
	266	if (unlikely(!count))
	267	return count;
	268
	269	msg[0].addr = client->addr;
	270	msg[0].flags = 0;
	271	msg[0].len = 1;
	272	msg[0].buf = buf;
	273
	274	buf[0] = 8 + off;
	275
	276	msg[1].addr = client->addr;
	277	msg[1].flags = I2C_M_RD;
	278	msg[1].len = count;
	279	msg[1].buf = buf;
	280
	281	result = i2c_transfer(to_i2c_adapter(client->dev.parent), msg, 2);
	282	if (result != 2) {
	283	dev_err(&client->dev, "%s error %d\n", "nvram read", result);
	284	return -EIO;
	285	}
	286	return count;
	287	}
	288
	289	static ssize_t
	290	ds1307_nvram_write(struct kobject kobj, struct bin_attribute attr,
	291	char *buf, loff_t off, size_t count)
	292	{
	293	struct i2c_client *client;
	294	u8 buffer[NVRAM_SIZE + 1];
	295	int ret;
	296
	297	client = to_i2c_client(container_of(kobj, struct device, kobj));
	298
	299	if (unlikely(off >= NVRAM_SIZE))
	300	return -EFBIG;
	301	if ((off + count) > NVRAM_SIZE)
	302	count = NVRAM_SIZE - off;
	303	if (unlikely(!count))
	304	return count;
	305
	306	buffer[0] = 8 + off;
	307	memcpy(buffer + 1, buf, count);
	308
	309	ret = i2c_master_send(client, buffer, count + 1);
310	return (ret < 0) ? ret : (ret - 1);
311	}
312
313	static struct bin_attribute nvram = {
314	.attr = {
315	.name = "nvram",
316	.mode = S_IRUGO \| S_IWUSR,
317	.owner = THIS_MODULE,
318	},
319
320	.read = ds1307_nvram_read,
321	.write = ds1307_nvram_write,
322	.size = NVRAM_SIZE,
323	};
324
325	/----------------------------------------------------------------------/
326
1abb0dc9 DB	327	static struct i2c_driver ds1307_driver;
1abb0dc9 DB	328
c065f35c	329	static int __devinit ds1307_probe(struct i2c_client *client)
1abb0dc9 DB	330	{
	331	struct ds1307 *ds1307;
	332	int err = -ENODEV;
1abb0dc9	333	int tmp;
045e0e85	334	const struct chip_desc *chip;
c065f35c	335	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
1abb0dc9	336
c065f35c DB	337	chip = find_chip(client->name);
	338	if (!chip) {
	339	dev_err(&client->dev, "unknown chip type '%s'\n",
	340	client->name);
	341	return -ENODEV;
1abb0dc9 DB	342	}
1abb0dc9 DB	343
c065f35c DB	344	if (!i2c_check_functionality(adapter,
	345	I2C_FUNC_I2C \| I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
	346	return -EIO;
	347
	348	if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL)))
	349	return -ENOMEM;
045e0e85 DB	350
045e0e85 DB	351	ds1307->client = client;
1abb0dc9 DB	352	i2c_set_clientdata(client, ds1307);
	353
	354	ds1307->msg[0].addr = client->addr;
	355	ds1307->msg[0].flags = 0;
	356	ds1307->msg[0].len = 1;
	357	ds1307->msg[0].buf = &ds1307->reg_addr;
	358
	359	ds1307->msg[1].addr = client->addr;
	360	ds1307->msg[1].flags = I2C_M_RD;
	361	ds1307->msg[1].len = sizeof(ds1307->regs);
	362	ds1307->msg[1].buf = ds1307->regs;
	363
045e0e85 DB	364	ds1307->type = chip->type;
	365
	366	switch (ds1307->type) {
	367	case ds_1337:
	368	case ds_1339:
1abb0dc9 DB	369	ds1307->reg_addr = DS1337_REG_CONTROL;
	370	ds1307->msg[1].len = 2;
	371
be5f59f4	372	/* get registers that the "rtc" read below won't read... */
045e0e85	373	tmp = i2c_transfer(adapter, ds1307->msg, 2);
1abb0dc9 DB	374	if (tmp != 2) {
	375	pr_debug("read error %d\n", tmp);
	376	err = -EIO;
	377	goto exit_free;
	378	}
	379
	380	ds1307->reg_addr = 0;
	381	ds1307->msg[1].len = sizeof(ds1307->regs);
	382
be5f59f4 RG	383	/* oscillator off? turn it on, so clock can tick. */
	384	if (ds1307->regs[0] & DS1337_BIT_nEOSC)
	385	i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
	386	ds1307->regs[0] & ~DS1337_BIT_nEOSC);
	387
	388	/* oscillator fault? clear flag, and warn */
	389	if (ds1307->regs[1] & DS1337_BIT_OSF) {
	390	i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
	391	ds1307->regs[1] & ~DS1337_BIT_OSF);
	392	dev_warn(&client->dev, "SET TIME!\n");
1abb0dc9	393	}
045e0e85 DB	394	break;
	395	default:
	396	break;
	397	}
1abb0dc9 DB	398
	399	read_rtc:
	400	/* read RTC registers */
	401
045e0e85	402	tmp = i2c_transfer(adapter, ds1307->msg, 2);
1abb0dc9 DB	403	if (tmp != 2) {
	404	pr_debug("read error %d\n", tmp);
	405	err = -EIO;
	406	goto exit_free;
	407	}
	408
	409	/* minimal sanity checking; some chips (like DS1340) don't
	410	* specify the extra bits as must-be-zero, but there are
	411	* still a few values that are clearly out-of-range.
	412	*/
	413	tmp = ds1307->regs[DS1307_REG_SECS];
045e0e85	414	switch (ds1307->type) {
be5f59f4 RG	415	case ds_1340:
	416	/* FIXME read register with DS1340_BIT_OSF, use that to
	417	* trigger the "set time" warning (after restarting the
	418	* oscillator!) instead of this weaker ds1307/m41t00 test.
	419	*/
045e0e85	420	case ds_1307:
045e0e85	421	case m41t00:
be5f59f4	422	/* clock halted? turn it on, so clock can tick. */
045e0e85	423	if (tmp & DS1307_BIT_CH) {
be5f59f4 RG	424	i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
be5f59f4 RG	425	dev_warn(&client->dev, "SET TIME!\n");
045e0e85	426	goto read_rtc;
1abb0dc9	427	}
045e0e85	428	break;
be5f59f4 RG	429	case ds_1338:
be5f59f4 RG	430	/* clock halted? turn it on, so clock can tick. */
045e0e85	431	if (tmp & DS1307_BIT_CH)
be5f59f4 RG	432	i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
	433
	434	/* oscillator fault? clear flag, and warn */
	435	if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
	436	i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
bd16f9eb	437	ds1307->regs[DS1307_REG_CONTROL]
be5f59f4 RG	438	& ~DS1338_BIT_OSF);
	439	dev_warn(&client->dev, "SET TIME!\n");
	440	goto read_rtc;
	441	}
045e0e85	442	break;
c065f35c DB	443	case ds_1337:
c065f35c DB	444	case ds_1339:
045e0e85	445	break;
1abb0dc9	446	}
045e0e85 DB	447
045e0e85 DB	448	tmp = ds1307->regs[DS1307_REG_SECS];
1abb0dc9 DB	449	tmp = BCD2BIN(tmp & 0x7f);
1abb0dc9 DB	450	if (tmp > 60)
c065f35c	451	goto exit_bad;
1abb0dc9 DB	452	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);
1abb0dc9 DB	453	if (tmp > 60)
c065f35c	454	goto exit_bad;
1abb0dc9 DB	455
	456	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
	457	if (tmp == 0 \|\| tmp > 31)
c065f35c	458	goto exit_bad;
1abb0dc9 DB	459
	460	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
	461	if (tmp == 0 \|\| tmp > 12)
c065f35c	462	goto exit_bad;
1abb0dc9	463
1abb0dc9	464	tmp = ds1307->regs[DS1307_REG_HOUR];
c065f35c DB	465	switch (ds1307->type) {
	466	case ds_1340:
	467	case m41t00:
	468	/* NOTE: ignores century bits; fix before deploying
	469	* systems that will run through year 2100.
	470	*/
	471	break;
	472	default:
	473	if (!(tmp & DS1307_BIT_12HR))
	474	break;
	475
	476	/* Be sure we're in 24 hour mode. Multi-master systems
	477	* take note...
	478	*/
	479	tmp = BCD2BIN(tmp & 0x1f);
	480	if (tmp == 12)
	481	tmp = 0;
	482	if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
	483	tmp += 12;
1abb0dc9 DB	484	i2c_smbus_write_byte_data(client,
	485	DS1307_REG_HOUR,
	486	BIN2BCD(tmp));
	487	}
	488
1abb0dc9 DB	489	ds1307->rtc = rtc_device_register(client->name, &client->dev,
	490	&ds13xx_rtc_ops, THIS_MODULE);
	491	if (IS_ERR(ds1307->rtc)) {
	492	err = PTR_ERR(ds1307->rtc);
	493	dev_err(&client->dev,
	494	"unable to register the class device\n");
c065f35c	495	goto exit_free;
1abb0dc9 DB	496	}
1abb0dc9 DB	497
682d73f6 DB	498	if (chip->nvram56) {
	499	err = sysfs_create_bin_file(&client->dev.kobj, &nvram);
	500	if (err == 0) {
	501	ds1307->has_nvram = true;
	502	dev_info(&client->dev, "56 bytes nvram\n");
	503	}
	504	}
	505
1abb0dc9 DB	506	return 0;
1abb0dc9 DB	507
c065f35c DB	508	exit_bad:
	509	dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
	510	"bogus register",
	511	ds1307->regs[0], ds1307->regs[1],
	512	ds1307->regs[2], ds1307->regs[3],
	513	ds1307->regs[4], ds1307->regs[5],
	514	ds1307->regs[6]);
	515
1abb0dc9 DB	516	exit_free:
1abb0dc9 DB	517	kfree(ds1307);
1abb0dc9 DB	518	return err;
	519	}
	520
c065f35c	521	static int __devexit ds1307_remove(struct i2c_client *client)
1abb0dc9	522	{
1abb0dc9 DB	523	struct ds1307 *ds1307 = i2c_get_clientdata(client);
1abb0dc9 DB	524
682d73f6 DB	525	if (ds1307->has_nvram)
	526	sysfs_remove_bin_file(&client->dev.kobj, &nvram);
	527
1abb0dc9	528	rtc_device_unregister(ds1307->rtc);
1abb0dc9 DB	529	kfree(ds1307);
	530	return 0;
	531	}
	532
	533	static struct i2c_driver ds1307_driver = {
	534	.driver = {
c065f35c	535	.name = "rtc-ds1307",
1abb0dc9 DB	536	.owner = THIS_MODULE,
1abb0dc9 DB	537	},
c065f35c DB	538	.probe = ds1307_probe,
c065f35c DB	539	.remove = __devexit_p(ds1307_remove),
1abb0dc9 DB	540	};
	541
	542	static int __init ds1307_init(void)
	543	{
	544	return i2c_add_driver(&ds1307_driver);
	545	}
	546	module_init(ds1307_init);
	547
	548	static void __exit ds1307_exit(void)
	549	{
	550	i2c_del_driver(&ds1307_driver);
	551	}
	552	module_exit(ds1307_exit);
	553
	554	MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
	555	MODULE_LICENSE("GPL");