[deliverable/linux.git] / drivers / rtc / rtc-ds1672.c

/*
 * An rtc/i2c driver for the Dallas DS1672
 * Copyright 2005-06 Tower Technologies
 *
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 * 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/i2c.h>
#include <linux/rtc.h>
#include <linux/module.h>

#define DRV_VERSION "0.4"

/* Registers */

#define DS1672_REG_CNT_BASE	0
#define DS1672_REG_CONTROL	4
#define DS1672_REG_TRICKLE	5

#define DS1672_REG_CONTROL_EOSC	0x80

static struct i2c_driver ds1672_driver;

/*
 * In the routines that deal directly with the ds1672 hardware, we use
 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
 * Epoch is initialized as 2000. Time is set to UTC.
 */
static int ds1672_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
	unsigned long time;
	unsigned char addr = DS1672_REG_CNT_BASE;
	unsigned char buf[4];

	struct i2c_msg msgs[] = {
		{/* setup read ptr */
			.addr = client->addr,
			.len = 1,
			.buf = &addr
		},
		{/* read date */
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = 4,
			.buf = buf
		},
	};

	/* read date registers */
	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
		dev_err(&client->dev, "%s: read error\n", __func__);
		return -EIO;
	}

	dev_dbg(&client->dev,
		"%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
		__func__, buf[0], buf[1], buf[2], buf[3]);

	time = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];

	rtc_time_to_tm(time, tm);

	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
		"mday=%d, mon=%d, year=%d, wday=%d\n",
		__func__, tm->tm_sec, tm->tm_min, tm->tm_hour,
		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

	return 0;
}

static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
{
	int xfer;
	unsigned char buf[6];

	buf[0] = DS1672_REG_CNT_BASE;
	buf[1] = secs & 0x000000FF;
	buf[2] = (secs & 0x0000FF00) >> 8;
	buf[3] = (secs & 0x00FF0000) >> 16;
	buf[4] = (secs & 0xFF000000) >> 24;
	buf[5] = 0;		/* set control reg to enable counting */

	xfer = i2c_master_send(client, buf, 6);
	if (xfer != 6) {
		dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
		return -EIO;
	}

	return 0;
}

static int ds1672_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	return ds1672_get_datetime(to_i2c_client(dev), tm);
}

static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
{
	return ds1672_set_mmss(to_i2c_client(dev), secs);
}

static int ds1672_get_control(struct i2c_client *client, u8 *status)
{
	unsigned char addr = DS1672_REG_CONTROL;

	struct i2c_msg msgs[] = {
		{/* setup read ptr */
			.addr = client->addr,
			.len = 1,
			.buf = &addr
		},
		{/* read control */
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = 1,
			.buf = status
		},
	};

	/* read control register */
	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
		dev_err(&client->dev, "%s: read error\n", __func__);
		return -EIO;
	}

	return 0;
}

/* following are the sysfs callback functions */
static ssize_t show_control(struct device *dev, struct device_attribute *attr,
			    char *buf)
{
	struct i2c_client *client = to_i2c_client(dev);
	u8 control;
	int err;

	err = ds1672_get_control(client, &control);
	if (err)
		return err;

	return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
		       ? "disabled" : "enabled");
}

static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);

static const struct rtc_class_ops ds1672_rtc_ops = {
	.read_time = ds1672_rtc_read_time,
	.set_mmss = ds1672_rtc_set_mmss,
};

static int ds1672_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	int err = 0;
	u8 control;
	struct rtc_device *rtc;

	dev_dbg(&client->dev, "%s\n", __func__);

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

	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");

	rtc = devm_rtc_device_register(&client->dev, ds1672_driver.driver.name,
				  &ds1672_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	i2c_set_clientdata(client, rtc);

	/* read control register */
	err = ds1672_get_control(client, &control);
	if (err) {
		dev_warn(&client->dev, "Unable to read the control register\n");
	}

	if (control & DS1672_REG_CONTROL_EOSC)
		dev_warn(&client->dev, "Oscillator not enabled. "
			 "Set time to enable.\n");

	/* Register sysfs hooks */
	err = device_create_file(&client->dev, &dev_attr_control);
	if (err)
		dev_err(&client->dev, "Unable to create sysfs entry: %s\n",
			dev_attr_control.attr.name);

	return 0;
}

static struct i2c_device_id ds1672_id[] = {
	{ "ds1672", 0 },
	{ }
};

static struct i2c_driver ds1672_driver = {
	.driver = {
		   .name = "rtc-ds1672",
		   },
	.probe = &ds1672_probe,
	.id_table = ds1672_id,
};

module_i2c_driver(ds1672_driver);

MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
Commit	Line	Data
	1	/*
	2	* An rtc/i2c driver for the Dallas DS1672
	3	* Copyright 2005-06 Tower Technologies
	4	*
	5	* Author: Alessandro Zummo <a.zummo@towertech.it>
	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/i2c.h>
	13	#include <linux/rtc.h>
	14	#include <linux/module.h>
	15
	16	#define DRV_VERSION "0.4"
	17
	18	/* Registers */
	19
	20	#define DS1672_REG_CNT_BASE 0
	21	#define DS1672_REG_CONTROL 4
	22	#define DS1672_REG_TRICKLE 5
	23
	24	#define DS1672_REG_CONTROL_EOSC 0x80
	25
	26	static struct i2c_driver ds1672_driver;
	27
	28	/*
	29	* In the routines that deal directly with the ds1672 hardware, we use
	30	* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
	31	* Epoch is initialized as 2000. Time is set to UTC.
	32	*/
	33	static int ds1672_get_datetime(struct i2c_client client, struct rtc_time tm)
	34	{
	35	unsigned long time;
	36	unsigned char addr = DS1672_REG_CNT_BASE;
	37	unsigned char buf[4];
	38
	39	struct i2c_msg msgs[] = {
	40	{/* setup read ptr */
	41	.addr = client->addr,
	42	.len = 1,
	43	.buf = &addr
	44	},
	45	{/* read date */
	46	.addr = client->addr,
	47	.flags = I2C_M_RD,
	48	.len = 4,
	49	.buf = buf
	50	},
	51	};
	52
	53	/* read date registers */
	54	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
	55	dev_err(&client->dev, "%s: read error\n", __func__);
	56	return -EIO;
	57	}
	58
	59	dev_dbg(&client->dev,
	60	"%s: raw read data - counters=%02x,%02x,%02x,%02x\n",
	61	__func__, buf[0], buf[1], buf[2], buf[3]);
	62
	63	time = (buf[3] << 24) \| (buf[2] << 16) \| (buf[1] << 8) \| buf[0];
	64
	65	rtc_time_to_tm(time, tm);
	66
	67	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
	68	"mday=%d, mon=%d, year=%d, wday=%d\n",
	69	__func__, tm->tm_sec, tm->tm_min, tm->tm_hour,
	70	tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
	71
	72	return 0;
	73	}
	74
	75	static int ds1672_set_mmss(struct i2c_client *client, unsigned long secs)
	76	{
	77	int xfer;
	78	unsigned char buf[6];
	79
	80	buf[0] = DS1672_REG_CNT_BASE;
	81	buf[1] = secs & 0x000000FF;
	82	buf[2] = (secs & 0x0000FF00) >> 8;
	83	buf[3] = (secs & 0x00FF0000) >> 16;
	84	buf[4] = (secs & 0xFF000000) >> 24;
	85	buf[5] = 0; /* set control reg to enable counting */
	86
	87	xfer = i2c_master_send(client, buf, 6);
	88	if (xfer != 6) {
	89	dev_err(&client->dev, "%s: send: %d\n", __func__, xfer);
	90	return -EIO;
	91	}
	92
	93	return 0;
	94	}
	95
	96	static int ds1672_rtc_read_time(struct device dev, struct rtc_time tm)
	97	{
	98	return ds1672_get_datetime(to_i2c_client(dev), tm);
	99	}
	100
	101	static int ds1672_rtc_set_mmss(struct device *dev, unsigned long secs)
	102	{
	103	return ds1672_set_mmss(to_i2c_client(dev), secs);
	104	}
	105
	106	static int ds1672_get_control(struct i2c_client client, u8 status)
	107	{
	108	unsigned char addr = DS1672_REG_CONTROL;
	109
	110	struct i2c_msg msgs[] = {
	111	{/* setup read ptr */
	112	.addr = client->addr,
	113	.len = 1,
	114	.buf = &addr
	115	},
	116	{/* read control */
	117	.addr = client->addr,
	118	.flags = I2C_M_RD,
	119	.len = 1,
	120	.buf = status
	121	},
	122	};
	123
	124	/* read control register */
	125	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
	126	dev_err(&client->dev, "%s: read error\n", __func__);
	127	return -EIO;
	128	}
	129
	130	return 0;
	131	}
	132
	133	/* following are the sysfs callback functions */
	134	static ssize_t show_control(struct device dev, struct device_attribute attr,
	135	char *buf)
	136	{
	137	struct i2c_client *client = to_i2c_client(dev);
	138	u8 control;
	139	int err;
	140
	141	err = ds1672_get_control(client, &control);
	142	if (err)
	143	return err;
	144
	145	return sprintf(buf, "%s\n", (control & DS1672_REG_CONTROL_EOSC)
	146	? "disabled" : "enabled");
	147	}
	148
	149	static DEVICE_ATTR(control, S_IRUGO, show_control, NULL);
	150
	151	static const struct rtc_class_ops ds1672_rtc_ops = {
	152	.read_time = ds1672_rtc_read_time,
	153	.set_mmss = ds1672_rtc_set_mmss,
	154	};
	155
	156	static int ds1672_probe(struct i2c_client *client,
	157	const struct i2c_device_id *id)
	158	{
	159	int err = 0;
	160	u8 control;
	161	struct rtc_device *rtc;
	162
	163	dev_dbg(&client->dev, "%s\n", __func__);
	164
	165	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	166	return -ENODEV;
	167
	168	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
	169
	170	rtc = devm_rtc_device_register(&client->dev, ds1672_driver.driver.name,
	171	&ds1672_rtc_ops, THIS_MODULE);
	172
	173	if (IS_ERR(rtc))
	174	return PTR_ERR(rtc);
	175
	176	i2c_set_clientdata(client, rtc);
	177
	178	/* read control register */
	179	err = ds1672_get_control(client, &control);
	180	if (err) {
	181	dev_warn(&client->dev, "Unable to read the control register\n");
	182	}
	183
	184	if (control & DS1672_REG_CONTROL_EOSC)
	185	dev_warn(&client->dev, "Oscillator not enabled. "
	186	"Set time to enable.\n");
	187
	188	/* Register sysfs hooks */
	189	err = device_create_file(&client->dev, &dev_attr_control);
	190	if (err)
	191	dev_err(&client->dev, "Unable to create sysfs entry: %s\n",
	192	dev_attr_control.attr.name);
	193
	194	return 0;
	195	}
	196
	197	static struct i2c_device_id ds1672_id[] = {
	198	{ "ds1672", 0 },
	199	{ }
	200	};
	201
	202	static struct i2c_driver ds1672_driver = {
	203	.driver = {
	204	.name = "rtc-ds1672",
	205	},
	206	.probe = &ds1672_probe,
	207	.id_table = ds1672_id,
	208	};
	209
	210	module_i2c_driver(ds1672_driver);
	211
	212	MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
	213	MODULE_DESCRIPTION("Dallas/Maxim DS1672 timekeeper driver");
	214	MODULE_LICENSE("GPL");
	215	MODULE_VERSION(DRV_VERSION);