[deliverable/linux.git] / drivers / rtc / rtc-pcf8583.c

/*
 *  drivers/rtc/rtc-pcf8583.c
 *
 *  Copyright (C) 2000 Russell King
 *  Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix
 *
 * 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 PCF8583 RTC & RAM chip
 *
 *  Converted to the generic RTC susbsystem by G. Liakhovetski (2006)
 */
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/bcd.h>

struct rtc_mem {
	unsigned int	loc;
	unsigned int	nr;
	unsigned char	*data;
};

struct pcf8583 {
	struct rtc_device *rtc;
	unsigned char ctrl;
};

#define CTRL_STOP	0x80
#define CTRL_HOLD	0x40
#define CTRL_32KHZ	0x00
#define CTRL_MASK	0x08
#define CTRL_ALARMEN	0x04
#define CTRL_ALARM	0x02
#define CTRL_TIMER	0x01


static struct i2c_driver pcf8583_driver;

#define get_ctrl(x)    ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl
#define set_ctrl(x, v) get_ctrl(x) = v

#define CMOS_YEAR	(64 + 128)
#define CMOS_CHECKSUM	(63)

static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt)
{
	unsigned char buf[8], addr[1] = { 1 };
	struct i2c_msg msgs[2] = {
		{
			.addr = client->addr,
			.flags = 0,
			.len = 1,
			.buf = addr,
		}, {
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = 6,
			.buf = buf,
		}
	};
	int ret;

	memset(buf, 0, sizeof(buf));

	ret = i2c_transfer(client->adapter, msgs, 2);
	if (ret == 2) {
		dt->tm_year = buf[4] >> 6;
		dt->tm_wday = buf[5] >> 5;

		buf[4] &= 0x3f;
		buf[5] &= 0x1f;

		dt->tm_sec = bcd2bin(buf[1]);
		dt->tm_min = bcd2bin(buf[2]);
		dt->tm_hour = bcd2bin(buf[3]);
		dt->tm_mday = bcd2bin(buf[4]);
		dt->tm_mon = bcd2bin(buf[5]) - 1;
	}

	return ret == 2 ? 0 : -EIO;
}

static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo)
{
	unsigned char buf[8];
	int ret, len = 6;

	buf[0] = 0;
	buf[1] = get_ctrl(client) | 0x80;
	buf[2] = 0;
	buf[3] = bin2bcd(dt->tm_sec);
	buf[4] = bin2bcd(dt->tm_min);
	buf[5] = bin2bcd(dt->tm_hour);

	if (datetoo) {
		len = 8;
		buf[6] = bin2bcd(dt->tm_mday) | (dt->tm_year << 6);
		buf[7] = bin2bcd(dt->tm_mon + 1)  | (dt->tm_wday << 5);
	}

	ret = i2c_master_send(client, (char *)buf, len);
	if (ret != len)
		return -EIO;

	buf[1] = get_ctrl(client);
	ret = i2c_master_send(client, (char *)buf, 2);

	return ret == 2 ? 0 : -EIO;
}

static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)
{
	*ctrl = get_ctrl(client);
	return 0;
}

static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)
{
	unsigned char buf[2];

	buf[0] = 0;
	buf[1] = *ctrl;
	set_ctrl(client, *ctrl);

	return i2c_master_send(client, (char *)buf, 2);
}

static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem)
{
	unsigned char addr[1];
	struct i2c_msg msgs[2] = {
		{
			.addr = client->addr,
			.flags = 0,
			.len = 1,
			.buf = addr,
		}, {
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = mem->nr,
			.buf = mem->data,
		}
	};

	if (mem->loc < 8)
		return -EINVAL;

	addr[0] = mem->loc;

	return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
}

static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem)
{
	unsigned char buf[9];
	int ret;

	if (mem->loc < 8 || mem->nr > 8)
		return -EINVAL;

	buf[0] = mem->loc;
	memcpy(buf + 1, mem->data, mem->nr);

	ret = i2c_master_send(client, buf, mem->nr + 1);
	return ret == mem->nr + 1 ? 0 : -EIO;
}

static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned char ctrl, year[2];
	struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year };
	int real_year, year_offset, err;

	/*
	 * Ensure that the RTC is running.
	 */
	pcf8583_get_ctrl(client, &ctrl);
	if (ctrl & (CTRL_STOP | CTRL_HOLD)) {
		unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD);

		dev_warn(dev, "resetting control %02x -> %02x\n",
			ctrl, new_ctrl);

		err = pcf8583_set_ctrl(client, &new_ctrl);
		if (err < 0)
			return err;
	}

	if (pcf8583_get_datetime(client, tm) ||
	    pcf8583_read_mem(client, &mem))
		return -EIO;

	real_year = year[0];

	/*
	 * The RTC year holds the LSB two bits of the current
	 * year, which should reflect the LSB two bits of the
	 * CMOS copy of the year.  Any difference indicates
	 * that we have to correct the CMOS version.
	 */
	year_offset = tm->tm_year - (real_year & 3);
	if (year_offset < 0)
		/*
		 * RTC year wrapped.  Adjust it appropriately.
		 */
		year_offset += 4;

	tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;

	return 0;
}

static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct i2c_client *client = to_i2c_client(dev);
	unsigned char year[2], chk;
	struct rtc_mem cmos_year  = { CMOS_YEAR, sizeof(year), year };
	struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk };
	unsigned int proper_year = tm->tm_year + 1900;
	int ret;

	/*
	 * The RTC's own 2-bit year must reflect the least
	 * significant two bits of the CMOS year.
	 */

	ret = pcf8583_set_datetime(client, tm, 1);
	if (ret)
		return ret;

	ret = pcf8583_read_mem(client, &cmos_check);
	if (ret)
		return ret;

	ret = pcf8583_read_mem(client, &cmos_year);
	if (ret)
		return ret;

	chk -= year[1] + year[0];

	year[1] = proper_year / 100;
	year[0] = proper_year % 100;

	chk += year[1] + year[0];

	ret = pcf8583_write_mem(client, &cmos_year);

	if (ret)
		return ret;

	ret = pcf8583_write_mem(client, &cmos_check);

	return ret;
}

static const struct rtc_class_ops pcf8583_rtc_ops = {
	.read_time	= pcf8583_rtc_read_time,
	.set_time	= pcf8583_rtc_set_time,
};

static int pcf8583_probe(struct i2c_client *client,
				const struct i2c_device_id *id)
{
	struct pcf8583 *pcf8583;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
		return -ENODEV;

	pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583),
				GFP_KERNEL);
	if (!pcf8583)
		return -ENOMEM;

	i2c_set_clientdata(client, pcf8583);

	pcf8583->rtc = devm_rtc_device_register(&client->dev,
				pcf8583_driver.driver.name,
				&pcf8583_rtc_ops, THIS_MODULE);

	if (IS_ERR(pcf8583->rtc))
		return PTR_ERR(pcf8583->rtc);

	return 0;
}

static const struct i2c_device_id pcf8583_id[] = {
	{ "pcf8583", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, pcf8583_id);

static struct i2c_driver pcf8583_driver = {
	.driver = {
		.name	= "pcf8583",
		.owner	= THIS_MODULE,
	},
	.probe		= pcf8583_probe,
	.id_table	= pcf8583_id,
};

module_i2c_driver(pcf8583_driver);

MODULE_AUTHOR("Russell King");
MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
9c0c5705 L	1	/*
	2	* drivers/rtc/rtc-pcf8583.c
	3	*
	4	* Copyright (C) 2000 Russell King
02bb584f	5	* Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix
9c0c5705 L	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	* Driver for PCF8583 RTC & RAM chip
	12	*
	13	* Converted to the generic RTC susbsystem by G. Liakhovetski (2006)
	14	*/
	15	#include <linux/module.h>
	16	#include <linux/i2c.h>
	17	#include <linux/slab.h>
77459b05	18	#include <linux/rtc.h>
9c0c5705 L	19	#include <linux/init.h>
	20	#include <linux/errno.h>
	21	#include <linux/bcd.h>
	22
	23	struct rtc_mem {
	24	unsigned int loc;
	25	unsigned int nr;
	26	unsigned char *data;
	27	};
	28
	29	struct pcf8583 {
9c0c5705 L	30	struct rtc_device *rtc;
	31	unsigned char ctrl;
	32	};
	33
	34	#define CTRL_STOP 0x80
	35	#define CTRL_HOLD 0x40
	36	#define CTRL_32KHZ 0x00
	37	#define CTRL_MASK 0x08
	38	#define CTRL_ALARMEN 0x04
	39	#define CTRL_ALARM 0x02
	40	#define CTRL_TIMER 0x01
	41
9c0c5705 L	42
	43	static struct i2c_driver pcf8583_driver;
	44
	45	#define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl
	46	#define set_ctrl(x, v) get_ctrl(x) = v
	47
	48	#define CMOS_YEAR (64 + 128)
	49	#define CMOS_CHECKSUM (63)
	50
	51	static int pcf8583_get_datetime(struct i2c_client client, struct rtc_time dt)
	52	{
	53	unsigned char buf[8], addr[1] = { 1 };
	54	struct i2c_msg msgs[2] = {
	55	{
	56	.addr = client->addr,
	57	.flags = 0,
	58	.len = 1,
	59	.buf = addr,
	60	}, {
	61	.addr = client->addr,
	62	.flags = I2C_M_RD,
	63	.len = 6,
	64	.buf = buf,
	65	}
	66	};
	67	int ret;
	68
	69	memset(buf, 0, sizeof(buf));
	70
	71	ret = i2c_transfer(client->adapter, msgs, 2);
	72	if (ret == 2) {
	73	dt->tm_year = buf[4] >> 6;
	74	dt->tm_wday = buf[5] >> 5;
	75
	76	buf[4] &= 0x3f;
	77	buf[5] &= 0x1f;
	78
fe20ba70 AB	79	dt->tm_sec = bcd2bin(buf[1]);
	80	dt->tm_min = bcd2bin(buf[2]);
	81	dt->tm_hour = bcd2bin(buf[3]);
	82	dt->tm_mday = bcd2bin(buf[4]);
	83	dt->tm_mon = bcd2bin(buf[5]) - 1;
9c0c5705 L	84	}
	85
	86	return ret == 2 ? 0 : -EIO;
	87	}
	88
	89	static int pcf8583_set_datetime(struct i2c_client client, struct rtc_time dt, int datetoo)
	90	{
	91	unsigned char buf[8];
	92	int ret, len = 6;
	93
	94	buf[0] = 0;
	95	buf[1] = get_ctrl(client) \| 0x80;
	96	buf[2] = 0;
fe20ba70 AB	97	buf[3] = bin2bcd(dt->tm_sec);
	98	buf[4] = bin2bcd(dt->tm_min);
	99	buf[5] = bin2bcd(dt->tm_hour);
9c0c5705 L	100
	101	if (datetoo) {
	102	len = 8;
fe20ba70 AB	103	buf[6] = bin2bcd(dt->tm_mday) \| (dt->tm_year << 6);
fe20ba70 AB	104	buf[7] = bin2bcd(dt->tm_mon + 1) \| (dt->tm_wday << 5);
9c0c5705 L	105	}
	106
	107	ret = i2c_master_send(client, (char *)buf, len);
	108	if (ret != len)
	109	return -EIO;
	110
	111	buf[1] = get_ctrl(client);
	112	ret = i2c_master_send(client, (char *)buf, 2);
	113
	114	return ret == 2 ? 0 : -EIO;
	115	}
	116
	117	static int pcf8583_get_ctrl(struct i2c_client client, unsigned char ctrl)
	118	{
	119	*ctrl = get_ctrl(client);
	120	return 0;
	121	}
	122
	123	static int pcf8583_set_ctrl(struct i2c_client client, unsigned char ctrl)
	124	{
	125	unsigned char buf[2];
	126
	127	buf[0] = 0;
	128	buf[1] = *ctrl;
	129	set_ctrl(client, *ctrl);
	130
	131	return i2c_master_send(client, (char *)buf, 2);
	132	}
	133
	134	static int pcf8583_read_mem(struct i2c_client client, struct rtc_mem mem)
	135	{
	136	unsigned char addr[1];
	137	struct i2c_msg msgs[2] = {
	138	{
	139	.addr = client->addr,
	140	.flags = 0,
	141	.len = 1,
	142	.buf = addr,
	143	}, {
	144	.addr = client->addr,
	145	.flags = I2C_M_RD,
	146	.len = mem->nr,
	147	.buf = mem->data,
	148	}
	149	};
	150
	151	if (mem->loc < 8)
	152	return -EINVAL;
	153
	154	addr[0] = mem->loc;
	155
	156	return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
	157	}
	158
	159	static int pcf8583_write_mem(struct i2c_client client, struct rtc_mem mem)
	160	{
037e291c JD	161	unsigned char buf[9];
037e291c JD	162	int ret;
9c0c5705	163
037e291c	164	if (mem->loc < 8 \|\| mem->nr > 8)
9c0c5705 L	165	return -EINVAL;
9c0c5705 L	166
037e291c JD	167	buf[0] = mem->loc;
037e291c JD	168	memcpy(buf + 1, mem->data, mem->nr);
9c0c5705	169
037e291c JD	170	ret = i2c_master_send(client, buf, mem->nr + 1);
037e291c JD	171	return ret == mem->nr + 1 ? 0 : -EIO;
9c0c5705 L	172	}
	173
	174	static int pcf8583_rtc_read_time(struct device dev, struct rtc_time tm)
	175	{
	176	struct i2c_client *client = to_i2c_client(dev);
	177	unsigned char ctrl, year[2];
	178	struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year };
	179	int real_year, year_offset, err;
	180
	181	/*
	182	* Ensure that the RTC is running.
	183	*/
	184	pcf8583_get_ctrl(client, &ctrl);
	185	if (ctrl & (CTRL_STOP \| CTRL_HOLD)) {
	186	unsigned char new_ctrl = ctrl & ~(CTRL_STOP \| CTRL_HOLD);
	187
79d13405 JH	188	dev_warn(dev, "resetting control %02x -> %02x\n",
79d13405 JH	189	ctrl, new_ctrl);
9c0c5705	190
d1bda80a SK	191	err = pcf8583_set_ctrl(client, &new_ctrl);
d1bda80a SK	192	if (err < 0)
9c0c5705 L	193	return err;
	194	}
	195
	196	if (pcf8583_get_datetime(client, tm) \|\|
	197	pcf8583_read_mem(client, &mem))
	198	return -EIO;
	199
	200	real_year = year[0];
	201
	202	/*
	203	* The RTC year holds the LSB two bits of the current
	204	* year, which should reflect the LSB two bits of the
	205	* CMOS copy of the year. Any difference indicates
	206	* that we have to correct the CMOS version.
	207	*/
	208	year_offset = tm->tm_year - (real_year & 3);
	209	if (year_offset < 0)
	210	/*
	211	* RTC year wrapped. Adjust it appropriately.
	212	*/
	213	year_offset += 4;
	214
0ed8f210	215	tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;
9c0c5705 L	216
	217	return 0;
	218	}
	219
	220	static int pcf8583_rtc_set_time(struct device dev, struct rtc_time tm)
	221	{
	222	struct i2c_client *client = to_i2c_client(dev);
	223	unsigned char year[2], chk;
	224	struct rtc_mem cmos_year = { CMOS_YEAR, sizeof(year), year };
	225	struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk };
0ed8f210	226	unsigned int proper_year = tm->tm_year + 1900;
9c0c5705 L	227	int ret;
	228
	229	/*
	230	* The RTC's own 2-bit year must reflect the least
	231	* significant two bits of the CMOS year.
	232	*/
	233
	234	ret = pcf8583_set_datetime(client, tm, 1);
	235	if (ret)
	236	return ret;
	237
	238	ret = pcf8583_read_mem(client, &cmos_check);
	239	if (ret)
	240	return ret;
	241
	242	ret = pcf8583_read_mem(client, &cmos_year);
	243	if (ret)
	244	return ret;
	245
	246	chk -= year[1] + year[0];
	247
0ed8f210 RK	248	year[1] = proper_year / 100;
0ed8f210 RK	249	year[0] = proper_year % 100;
9c0c5705 L	250
	251	chk += year[1] + year[0];
	252
	253	ret = pcf8583_write_mem(client, &cmos_year);
	254
	255	if (ret)
	256	return ret;
	257
	258	ret = pcf8583_write_mem(client, &cmos_check);
	259
	260	return ret;
	261	}
	262
ff8371ac	263	static const struct rtc_class_ops pcf8583_rtc_ops = {
9c0c5705 L	264	.read_time = pcf8583_rtc_read_time,
	265	.set_time = pcf8583_rtc_set_time,
	266	};
	267
02bb584f WS	268	static int pcf8583_probe(struct i2c_client *client,
02bb584f WS	269	const struct i2c_device_id *id)
9c0c5705	270	{
02bb584f	271	struct pcf8583 *pcf8583;
9c0c5705	272
02bb584f WS	273	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
02bb584f WS	274	return -ENODEV;
c018664c	275
4ad21183 JH	276	pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583),
4ad21183 JH	277	GFP_KERNEL);
02bb584f	278	if (!pcf8583)
9c0c5705 L	279	return -ENOMEM;
9c0c5705 L	280
b74d2caa AZ	281	i2c_set_clientdata(client, pcf8583);
b74d2caa AZ	282
4ad21183 JH	283	pcf8583->rtc = devm_rtc_device_register(&client->dev,
	284	pcf8583_driver.driver.name,
	285	&pcf8583_rtc_ops, THIS_MODULE);
9c0c5705	286
4ad21183 JH	287	if (IS_ERR(pcf8583->rtc))
4ad21183 JH	288	return PTR_ERR(pcf8583->rtc);
9c0c5705	289
02bb584f	290	return 0;
02bb584f	291	}
9c0c5705	292
02bb584f WS	293	static const struct i2c_device_id pcf8583_id[] = {
	294	{ "pcf8583", 0 },
	295	{ }
	296	};
	297	MODULE_DEVICE_TABLE(i2c, pcf8583_id);
9c0c5705	298
02bb584f WS	299	static struct i2c_driver pcf8583_driver = {
	300	.driver = {
	301	.name = "pcf8583",
	302	.owner = THIS_MODULE,
	303	},
	304	.probe = pcf8583_probe,
02bb584f WS	305	.id_table = pcf8583_id,
02bb584f WS	306	};
9c0c5705	307
0abc9201	308	module_i2c_driver(pcf8583_driver);
9c0c5705 L	309
	310	MODULE_AUTHOR("Russell King");
	311	MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
	312	MODULE_LICENSE("GPL");