[linux-2.6-block.git] / drivers / misc / ds1682.c

/*
 * Dallas Semiconductor DS1682 Elapsed Time Recorder device driver
 *
 * Written by: Grant Likely <grant.likely@secretlab.ca>
 *
 * Copyright (C) 2007 Secret Lab Technologies 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.
 */

/*
 * The DS1682 elapsed timer recorder is a simple device that implements
 * one elapsed time counter, one event counter, an alarm signal and 10
 * bytes of general purpose EEPROM.
 *
 * This driver provides access to the DS1682 counters and user data via
 * the sysfs.  The following attributes are added to the device node:
 *     elapsed_time (u32): Total elapsed event time in ms resolution
 *     alarm_time (u32): When elapsed time exceeds the value in alarm_time,
 *                       then the alarm pin is asserted.
 *     event_count (u16): number of times the event pin has gone low.
 *     eeprom (u8[10]): general purpose EEPROM
 *
 * Counter registers and user data are both read/write unless the device
 * has been write protected.  This driver does not support turning off write
 * protection.  Once write protection is turned on, it is impossible to
 * turn it off again, so I have left the feature out of this driver to avoid
 * accidental enabling, but it is trivial to add write protect support.
 *
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/sysfs.h>
#include <linux/ctype.h>
#include <linux/hwmon-sysfs.h>

/* Device registers */
#define DS1682_REG_CONFIG		0x00
#define DS1682_REG_ALARM		0x01
#define DS1682_REG_ELAPSED		0x05
#define DS1682_REG_EVT_CNTR		0x09
#define DS1682_REG_EEPROM		0x0b
#define DS1682_REG_RESET		0x1d
#define DS1682_REG_WRITE_DISABLE	0x1e
#define DS1682_REG_WRITE_MEM_DISABLE	0x1f

#define DS1682_EEPROM_SIZE		10

/*
 * Generic counter attributes
 */
static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr,
			   char *buf)
{
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
	struct i2c_client *client = to_i2c_client(dev);
	unsigned long long val, check;
	__le32 val_le = 0;
	int rc;

	dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name);

	/* Read the register */
	rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr,
					   (u8 *)&val_le);
	if (rc < 0)
		return -EIO;

	val = le32_to_cpu(val_le);

	if (sattr->index == DS1682_REG_ELAPSED) {
		int retries = 5;

		/* Detect and retry when a tick occurs mid-read */
		do {
			rc = i2c_smbus_read_i2c_block_data(client, sattr->index,
							   sattr->nr,
							   (u8 *)&val_le);
			if (rc < 0 || retries <= 0)
				return -EIO;

			check = val;
			val = le32_to_cpu(val_le);
			retries--;
		} while (val != check && val != (check + 1));
	}

	/* Format the output string and return # of bytes
	 * Special case: the 32 bit regs are time values with 1/4s
	 * resolution, scale them up to milliseconds
	 */
	return sprintf(buf, "%llu\n", (sattr->nr == 4) ? (val * 250) : val);
}

static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
	struct i2c_client *client = to_i2c_client(dev);
	u64 val;
	__le32 val_le;
	int rc;

	dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name);

	/* Decode input */
	rc = kstrtoull(buf, 0, &val);
	if (rc < 0) {
		dev_dbg(dev, "input string not a number\n");
		return -EINVAL;
	}

	/* Special case: the 32 bit regs are time values with 1/4s
	 * resolution, scale input down to quarter-seconds */
	if (sattr->nr == 4)
		do_div(val, 250);

	/* write out the value */
	val_le = cpu_to_le32(val);
	rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr,
					    (u8 *) & val_le);
	if (rc < 0) {
		dev_err(dev, "register write failed; reg=0x%x, size=%i\n",
			sattr->index, sattr->nr);
		return -EIO;
	}

	return count;
}

/*
 * Simple register attributes
 */
static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show,
			    ds1682_store, 4, DS1682_REG_ELAPSED);
static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show,
			    ds1682_store, 4, DS1682_REG_ALARM);
static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show,
			    ds1682_store, 2, DS1682_REG_EVT_CNTR);

static const struct attribute_group ds1682_group = {
	.attrs = (struct attribute *[]) {
		&sensor_dev_attr_elapsed_time.dev_attr.attr,
		&sensor_dev_attr_alarm_time.dev_attr.attr,
		&sensor_dev_attr_event_count.dev_attr.attr,
		NULL,
	},
};

/*
 * User data attribute
 */
static ssize_t ds1682_eeprom_read(struct file *filp, struct kobject *kobj,
				  struct bin_attribute *attr,
				  char *buf, loff_t off, size_t count)
{
	struct i2c_client *client = kobj_to_i2c_client(kobj);
	int rc;

	dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n",
		buf, off, count);

	rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off,
					   count, buf);
	if (rc < 0)
		return -EIO;

	return count;
}

static ssize_t ds1682_eeprom_write(struct file *filp, struct kobject *kobj,
				   struct bin_attribute *attr,
				   char *buf, loff_t off, size_t count)
{
	struct i2c_client *client = kobj_to_i2c_client(kobj);

	dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n",
		buf, off, count);

	/* Write out to the device */
	if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off,
					   count, buf) < 0)
		return -EIO;

	return count;
}

static const struct bin_attribute ds1682_eeprom_attr = {
	.attr = {
		.name = "eeprom",
		.mode = S_IRUGO | S_IWUSR,
	},
	.size = DS1682_EEPROM_SIZE,
	.read = ds1682_eeprom_read,
	.write = ds1682_eeprom_write,
};

/*
 * Called when a ds1682 device is matched with this driver
 */
static int ds1682_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	int rc;

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_I2C_BLOCK)) {
		dev_err(&client->dev, "i2c bus does not support the ds1682\n");
		rc = -ENODEV;
		goto exit;
	}

	rc = sysfs_create_group(&client->dev.kobj, &ds1682_group);
	if (rc)
		goto exit;

	rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
	if (rc)
		goto exit_bin_attr;

	return 0;

 exit_bin_attr:
	sysfs_remove_group(&client->dev.kobj, &ds1682_group);
 exit:
	return rc;
}

static int ds1682_remove(struct i2c_client *client)
{
	sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
	sysfs_remove_group(&client->dev.kobj, &ds1682_group);
	return 0;
}

static const struct i2c_device_id ds1682_id[] = {
	{ "ds1682", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ds1682_id);

static const struct of_device_id ds1682_of_match[] = {
	{ .compatible = "dallas,ds1682", },
	{}
};
MODULE_DEVICE_TABLE(of, ds1682_of_match);

static struct i2c_driver ds1682_driver = {
	.driver = {
		.name = "ds1682",
		.of_match_table = ds1682_of_match,
	},
	.probe = ds1682_probe,
	.remove = ds1682_remove,
	.id_table = ds1682_id,
};

module_i2c_driver(ds1682_driver);

MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
5162b75b GL	1	/*
	2	* Dallas Semiconductor DS1682 Elapsed Time Recorder device driver
	3	*
	4	* Written by: Grant Likely <grant.likely@secretlab.ca>
	5	*
	6	* Copyright (C) 2007 Secret Lab Technologies Ltd.
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
	13	/*
	14	* The DS1682 elapsed timer recorder is a simple device that implements
	15	* one elapsed time counter, one event counter, an alarm signal and 10
	16	* bytes of general purpose EEPROM.
	17	*
	18	* This driver provides access to the DS1682 counters and user data via
	19	* the sysfs. The following attributes are added to the device node:
	20	* elapsed_time (u32): Total elapsed event time in ms resolution
	21	* alarm_time (u32): When elapsed time exceeds the value in alarm_time,
	22	* then the alarm pin is asserted.
	23	* event_count (u16): number of times the event pin has gone low.
	24	* eeprom (u8[10]): general purpose EEPROM
	25	*
	26	* Counter registers and user data are both read/write unless the device
	27	* has been write protected. This driver does not support turning off write
	28	* protection. Once write protection is turned on, it is impossible to
	29	* turn it off again, so I have left the feature out of this driver to avoid
	30	* accidental enabling, but it is trivial to add write protect support.
	31	*
	32	*/
	33
	34	#include <linux/module.h>
5162b75b GL	35	#include <linux/i2c.h>
	36	#include <linux/string.h>
	37	#include <linux/list.h>
	38	#include <linux/sysfs.h>
	39	#include <linux/ctype.h>
	40	#include <linux/hwmon-sysfs.h>
	41
	42	/* Device registers */
	43	#define DS1682_REG_CONFIG 0x00
	44	#define DS1682_REG_ALARM 0x01
	45	#define DS1682_REG_ELAPSED 0x05
	46	#define DS1682_REG_EVT_CNTR 0x09
	47	#define DS1682_REG_EEPROM 0x0b
	48	#define DS1682_REG_RESET 0x1d
	49	#define DS1682_REG_WRITE_DISABLE 0x1e
	50	#define DS1682_REG_WRITE_MEM_DISABLE 0x1f
	51
	52	#define DS1682_EEPROM_SIZE 10
	53
	54	/*
	55	* Generic counter attributes
	56	*/
	57	static ssize_t ds1682_show(struct device dev, struct device_attribute attr,
	58	char *buf)
	59	{
	60	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
	61	struct i2c_client *client = to_i2c_client(dev);
066ed427	62	unsigned long long val, check;
2fa065fd	63	__le32 val_le = 0;
5162b75b GL	64	int rc;
	65
	66	dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name);
	67
	68	/* Read the register */
	69	rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr,
2fa065fd	70	(u8 *)&val_le);
5162b75b GL	71	if (rc < 0)
	72	return -EIO;
	73
2fa065fd	74	val = le32_to_cpu(val_le);
5162b75b	75
066ed427 TV	76	if (sattr->index == DS1682_REG_ELAPSED) {
	77	int retries = 5;
	78
	79	/* Detect and retry when a tick occurs mid-read */
	80	do {
	81	rc = i2c_smbus_read_i2c_block_data(client, sattr->index,
	82	sattr->nr,
	83	(u8 *)&val_le);
	84	if (rc < 0 \|\| retries <= 0)
	85	return -EIO;
	86
	87	check = val;
	88	val = le32_to_cpu(val_le);
	89	retries--;
	90	} while (val != check && val != (check + 1));
	91	}
	92
2fa065fd AS	93	/* Format the output string and return # of bytes
	94	* Special case: the 32 bit regs are time values with 1/4s
	95	* resolution, scale them up to milliseconds
	96	*/
	97	return sprintf(buf, "%llu\n", (sattr->nr == 4) ? (val * 250) : val);
5162b75b GL	98	}
	99
	100	static ssize_t ds1682_store(struct device dev, struct device_attribute attr,
	101	const char *buf, size_t count)
	102	{
	103	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
	104	struct i2c_client *client = to_i2c_client(dev);
5162b75b GL	105	u64 val;
	106	__le32 val_le;
	107	int rc;
	108
	109	dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name);
	110
	111	/* Decode input */
40300745 SB	112	rc = kstrtoull(buf, 0, &val);
40300745 SB	113	if (rc < 0) {
5162b75b GL	114	dev_dbg(dev, "input string not a number\n");
	115	return -EINVAL;
	116	}
	117
	118	/* Special case: the 32 bit regs are time values with 1/4s
	119	* resolution, scale input down to quarter-seconds */
	120	if (sattr->nr == 4)
	121	do_div(val, 250);
	122
	123	/* write out the value */
	124	val_le = cpu_to_le32(val);
	125	rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr,
	126	(u8 *) & val_le);
	127	if (rc < 0) {
	128	dev_err(dev, "register write failed; reg=0x%x, size=%i\n",
	129	sattr->index, sattr->nr);
	130	return -EIO;
	131	}
	132
	133	return count;
	134	}
	135
	136	/*
	137	* Simple register attributes
	138	*/
	139	static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO \| S_IWUSR, ds1682_show,
	140	ds1682_store, 4, DS1682_REG_ELAPSED);
	141	static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO \| S_IWUSR, ds1682_show,
	142	ds1682_store, 4, DS1682_REG_ALARM);
	143	static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO \| S_IWUSR, ds1682_show,
	144	ds1682_store, 2, DS1682_REG_EVT_CNTR);
	145
	146	static const struct attribute_group ds1682_group = {
	147	.attrs = (struct attribute *[]) {
	148	&sensor_dev_attr_elapsed_time.dev_attr.attr,
	149	&sensor_dev_attr_alarm_time.dev_attr.attr,
	150	&sensor_dev_attr_event_count.dev_attr.attr,
	151	NULL,
	152	},
	153	};
	154
	155	/*
	156	* User data attribute
	157	*/
2c3c8bea CW	158	static ssize_t ds1682_eeprom_read(struct file filp, struct kobject kobj,
2c3c8bea CW	159	struct bin_attribute *attr,
05bd711e	160	char *buf, loff_t off, size_t count)
5162b75b GL	161	{
	162	struct i2c_client *client = kobj_to_i2c_client(kobj);
	163	int rc;
	164
	165	dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n",
	166	buf, off, count);
	167
5162b75b GL	168	rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off,
	169	count, buf);
	170	if (rc < 0)
	171	return -EIO;
	172
	173	return count;
	174	}
	175
2c3c8bea CW	176	static ssize_t ds1682_eeprom_write(struct file filp, struct kobject kobj,
2c3c8bea CW	177	struct bin_attribute *attr,
05bd711e	178	char *buf, loff_t off, size_t count)
5162b75b GL	179	{
	180	struct i2c_client *client = kobj_to_i2c_client(kobj);
	181
	182	dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n",
	183	buf, off, count);
	184
5162b75b GL	185	/* Write out to the device */
	186	if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off,
	187	count, buf) < 0)
	188	return -EIO;
	189
	190	return count;
	191	}
	192
57daedf8	193	static const struct bin_attribute ds1682_eeprom_attr = {
5162b75b GL	194	.attr = {
	195	.name = "eeprom",
	196	.mode = S_IRUGO \| S_IWUSR,
5162b75b GL	197	},
	198	.size = DS1682_EEPROM_SIZE,
	199	.read = ds1682_eeprom_read,
	200	.write = ds1682_eeprom_write,
	201	};
	202
	203	/*
	204	* Called when a ds1682 device is matched with this driver
	205	*/
d2653e92 JD	206	static int ds1682_probe(struct i2c_client *client,
d2653e92 JD	207	const struct i2c_device_id *id)
5162b75b GL	208	{
	209	int rc;
	210
	211	if (!i2c_check_functionality(client->adapter,
	212	I2C_FUNC_SMBUS_I2C_BLOCK)) {
	213	dev_err(&client->dev, "i2c bus does not support the ds1682\n");
	214	rc = -ENODEV;
	215	goto exit;
	216	}
	217
	218	rc = sysfs_create_group(&client->dev.kobj, &ds1682_group);
	219	if (rc)
	220	goto exit;
	221
	222	rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
	223	if (rc)
	224	goto exit_bin_attr;
	225
	226	return 0;
	227
	228	exit_bin_attr:
	229	sysfs_remove_group(&client->dev.kobj, &ds1682_group);
	230	exit:
	231	return rc;
	232	}
	233
	234	static int ds1682_remove(struct i2c_client *client)
	235	{
	236	sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
	237	sysfs_remove_group(&client->dev.kobj, &ds1682_group);
	238	return 0;
	239	}
	240
3760f736 JD	241	static const struct i2c_device_id ds1682_id[] = {
	242	{ "ds1682", 0 },
	243	{ }
	244	};
	245	MODULE_DEVICE_TABLE(i2c, ds1682_id);
	246
5ef16854 JMC	247	static const struct of_device_id ds1682_of_match[] = {
	248	{ .compatible = "dallas,ds1682", },
	249	{}
	250	};
	251	MODULE_DEVICE_TABLE(of, ds1682_of_match);
	252
5162b75b GL	253	static struct i2c_driver ds1682_driver = {
	254	.driver = {
	255	.name = "ds1682",
5ef16854	256	.of_match_table = ds1682_of_match,
5162b75b GL	257	},
	258	.probe = ds1682_probe,
	259	.remove = ds1682_remove,
3760f736	260	.id_table = ds1682_id,
5162b75b GL	261	};
5162b75b GL	262
a64fe2ed	263	module_i2c_driver(ds1682_driver);
5162b75b GL	264
	265	MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
	266	MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
	267	MODULE_LICENSE("GPL");