[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/err.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 = {
		.loc = CMOS_YEAR,
		.nr = sizeof(year),
		.data = 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  = {
		.loc = CMOS_YEAR,
		.nr = sizeof(year),
		.data = year
	};
	struct rtc_mem cmos_check = {
		.loc = CMOS_CHECKSUM,
		.nr = 1,
		.data = &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);

	return PTR_ERR_OR_ZERO(pcf8583->rtc);
}

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",
	},
	.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	19	#include <linux/init.h>
ee605e0b	20	#include <linux/err.h>
9c0c5705 L	21	#include <linux/errno.h>
	22	#include <linux/bcd.h>
	23
	24	struct rtc_mem {
	25	unsigned int loc;
	26	unsigned int nr;
	27	unsigned char *data;
	28	};
	29
	30	struct pcf8583 {
9c0c5705 L	31	struct rtc_device *rtc;
	32	unsigned char ctrl;
	33	};
	34
	35	#define CTRL_STOP 0x80
	36	#define CTRL_HOLD 0x40
	37	#define CTRL_32KHZ 0x00
	38	#define CTRL_MASK 0x08
	39	#define CTRL_ALARMEN 0x04
	40	#define CTRL_ALARM 0x02
	41	#define CTRL_TIMER 0x01
	42
9c0c5705 L	43
	44	static struct i2c_driver pcf8583_driver;
	45
	46	#define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl
	47	#define set_ctrl(x, v) get_ctrl(x) = v
	48
	49	#define CMOS_YEAR (64 + 128)
	50	#define CMOS_CHECKSUM (63)
	51
	52	static int pcf8583_get_datetime(struct i2c_client client, struct rtc_time dt)
	53	{
	54	unsigned char buf[8], addr[1] = { 1 };
	55	struct i2c_msg msgs[2] = {
	56	{
	57	.addr = client->addr,
	58	.flags = 0,
	59	.len = 1,
	60	.buf = addr,
	61	}, {
	62	.addr = client->addr,
	63	.flags = I2C_M_RD,
	64	.len = 6,
	65	.buf = buf,
	66	}
	67	};
	68	int ret;
	69
	70	memset(buf, 0, sizeof(buf));
	71
	72	ret = i2c_transfer(client->adapter, msgs, 2);
	73	if (ret == 2) {
	74	dt->tm_year = buf[4] >> 6;
	75	dt->tm_wday = buf[5] >> 5;
	76
	77	buf[4] &= 0x3f;
	78	buf[5] &= 0x1f;
	79
fe20ba70 AB	80	dt->tm_sec = bcd2bin(buf[1]);
	81	dt->tm_min = bcd2bin(buf[2]);
	82	dt->tm_hour = bcd2bin(buf[3]);
	83	dt->tm_mday = bcd2bin(buf[4]);
	84	dt->tm_mon = bcd2bin(buf[5]) - 1;
9c0c5705 L	85	}
	86
	87	return ret == 2 ? 0 : -EIO;
	88	}
	89
	90	static int pcf8583_set_datetime(struct i2c_client client, struct rtc_time dt, int datetoo)
	91	{
	92	unsigned char buf[8];
	93	int ret, len = 6;
	94
	95	buf[0] = 0;
	96	buf[1] = get_ctrl(client) \| 0x80;
	97	buf[2] = 0;
fe20ba70 AB	98	buf[3] = bin2bcd(dt->tm_sec);
	99	buf[4] = bin2bcd(dt->tm_min);
	100	buf[5] = bin2bcd(dt->tm_hour);
9c0c5705 L	101
	102	if (datetoo) {
	103	len = 8;
fe20ba70 AB	104	buf[6] = bin2bcd(dt->tm_mday) \| (dt->tm_year << 6);
fe20ba70 AB	105	buf[7] = bin2bcd(dt->tm_mon + 1) \| (dt->tm_wday << 5);
9c0c5705 L	106	}
	107
	108	ret = i2c_master_send(client, (char *)buf, len);
	109	if (ret != len)
	110	return -EIO;
	111
	112	buf[1] = get_ctrl(client);
	113	ret = i2c_master_send(client, (char *)buf, 2);
	114
	115	return ret == 2 ? 0 : -EIO;
	116	}
	117
	118	static int pcf8583_get_ctrl(struct i2c_client client, unsigned char ctrl)
	119	{
	120	*ctrl = get_ctrl(client);
	121	return 0;
	122	}
	123
	124	static int pcf8583_set_ctrl(struct i2c_client client, unsigned char ctrl)
	125	{
	126	unsigned char buf[2];
	127
	128	buf[0] = 0;
	129	buf[1] = *ctrl;
	130	set_ctrl(client, *ctrl);
	131
	132	return i2c_master_send(client, (char *)buf, 2);
	133	}
	134
	135	static int pcf8583_read_mem(struct i2c_client client, struct rtc_mem mem)
	136	{
	137	unsigned char addr[1];
	138	struct i2c_msg msgs[2] = {
	139	{
	140	.addr = client->addr,
	141	.flags = 0,
	142	.len = 1,
	143	.buf = addr,
	144	}, {
	145	.addr = client->addr,
	146	.flags = I2C_M_RD,
	147	.len = mem->nr,
	148	.buf = mem->data,
	149	}
	150	};
	151
	152	if (mem->loc < 8)
	153	return -EINVAL;
	154
	155	addr[0] = mem->loc;
	156
	157	return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
	158	}
	159
	160	static int pcf8583_write_mem(struct i2c_client client, struct rtc_mem mem)
	161	{
037e291c JD	162	unsigned char buf[9];
037e291c JD	163	int ret;
9c0c5705	164
037e291c	165	if (mem->loc < 8 \|\| mem->nr > 8)
9c0c5705 L	166	return -EINVAL;
9c0c5705 L	167
037e291c JD	168	buf[0] = mem->loc;
037e291c JD	169	memcpy(buf + 1, mem->data, mem->nr);
9c0c5705	170
037e291c JD	171	ret = i2c_master_send(client, buf, mem->nr + 1);
037e291c JD	172	return ret == mem->nr + 1 ? 0 : -EIO;
9c0c5705 L	173	}
	174
	175	static int pcf8583_rtc_read_time(struct device dev, struct rtc_time tm)
	176	{
	177	struct i2c_client *client = to_i2c_client(dev);
	178	unsigned char ctrl, year[2];
473b8645 JL	179	struct rtc_mem mem = {
	180	.loc = CMOS_YEAR,
	181	.nr = sizeof(year),
	182	.data = year
	183	};
9c0c5705 L	184	int real_year, year_offset, err;
	185
	186	/*
	187	* Ensure that the RTC is running.
	188	*/
	189	pcf8583_get_ctrl(client, &ctrl);
	190	if (ctrl & (CTRL_STOP \| CTRL_HOLD)) {
	191	unsigned char new_ctrl = ctrl & ~(CTRL_STOP \| CTRL_HOLD);
	192
79d13405 JH	193	dev_warn(dev, "resetting control %02x -> %02x\n",
79d13405 JH	194	ctrl, new_ctrl);
9c0c5705	195
d1bda80a SK	196	err = pcf8583_set_ctrl(client, &new_ctrl);
d1bda80a SK	197	if (err < 0)
9c0c5705 L	198	return err;
	199	}
	200
	201	if (pcf8583_get_datetime(client, tm) \|\|
	202	pcf8583_read_mem(client, &mem))
	203	return -EIO;
	204
	205	real_year = year[0];
	206
	207	/*
	208	* The RTC year holds the LSB two bits of the current
	209	* year, which should reflect the LSB two bits of the
	210	* CMOS copy of the year. Any difference indicates
	211	* that we have to correct the CMOS version.
	212	*/
	213	year_offset = tm->tm_year - (real_year & 3);
	214	if (year_offset < 0)
	215	/*
	216	* RTC year wrapped. Adjust it appropriately.
	217	*/
	218	year_offset += 4;
	219
0ed8f210	220	tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;
9c0c5705 L	221
	222	return 0;
	223	}
	224
	225	static int pcf8583_rtc_set_time(struct device dev, struct rtc_time tm)
	226	{
	227	struct i2c_client *client = to_i2c_client(dev);
	228	unsigned char year[2], chk;
473b8645 JL	229	struct rtc_mem cmos_year = {
	230	.loc = CMOS_YEAR,
	231	.nr = sizeof(year),
	232	.data = year
	233	};
	234	struct rtc_mem cmos_check = {
	235	.loc = CMOS_CHECKSUM,
	236	.nr = 1,
	237	.data = &chk
	238	};
0ed8f210	239	unsigned int proper_year = tm->tm_year + 1900;
9c0c5705 L	240	int ret;
	241
	242	/*
	243	* The RTC's own 2-bit year must reflect the least
	244	* significant two bits of the CMOS year.
	245	*/
	246
	247	ret = pcf8583_set_datetime(client, tm, 1);
	248	if (ret)
	249	return ret;
	250
	251	ret = pcf8583_read_mem(client, &cmos_check);
	252	if (ret)
	253	return ret;
	254
	255	ret = pcf8583_read_mem(client, &cmos_year);
	256	if (ret)
	257	return ret;
	258
	259	chk -= year[1] + year[0];
	260
0ed8f210 RK	261	year[1] = proper_year / 100;
0ed8f210 RK	262	year[0] = proper_year % 100;
9c0c5705 L	263
	264	chk += year[1] + year[0];
	265
	266	ret = pcf8583_write_mem(client, &cmos_year);
	267
	268	if (ret)
	269	return ret;
	270
	271	ret = pcf8583_write_mem(client, &cmos_check);
	272
	273	return ret;
	274	}
	275
ff8371ac	276	static const struct rtc_class_ops pcf8583_rtc_ops = {
9c0c5705 L	277	.read_time = pcf8583_rtc_read_time,
	278	.set_time = pcf8583_rtc_set_time,
	279	};
	280
02bb584f WS	281	static int pcf8583_probe(struct i2c_client *client,
02bb584f WS	282	const struct i2c_device_id *id)
9c0c5705	283	{
02bb584f	284	struct pcf8583 *pcf8583;
9c0c5705	285
02bb584f WS	286	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
02bb584f WS	287	return -ENODEV;
c018664c	288
4ad21183 JH	289	pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583),
4ad21183 JH	290	GFP_KERNEL);
02bb584f	291	if (!pcf8583)
9c0c5705 L	292	return -ENOMEM;
9c0c5705 L	293
b74d2caa AZ	294	i2c_set_clientdata(client, pcf8583);
b74d2caa AZ	295
4ad21183 JH	296	pcf8583->rtc = devm_rtc_device_register(&client->dev,
	297	pcf8583_driver.driver.name,
	298	&pcf8583_rtc_ops, THIS_MODULE);
9c0c5705	299
dac30a98	300	return PTR_ERR_OR_ZERO(pcf8583->rtc);
02bb584f	301	}
9c0c5705	302
02bb584f WS	303	static const struct i2c_device_id pcf8583_id[] = {
	304	{ "pcf8583", 0 },
	305	{ }
	306	};
	307	MODULE_DEVICE_TABLE(i2c, pcf8583_id);
9c0c5705	308
02bb584f WS	309	static struct i2c_driver pcf8583_driver = {
	310	.driver = {
	311	.name = "pcf8583",
02bb584f WS	312	},
02bb584f WS	313	.probe = pcf8583_probe,
02bb584f WS	314	.id_table = pcf8583_id,
02bb584f WS	315	};
9c0c5705	316
0abc9201	317	module_i2c_driver(pcf8583_driver);
9c0c5705 L	318
	319	MODULE_AUTHOR("Russell King");
	320	MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
	321	MODULE_LICENSE("GPL");