[linux-2.6-block.git] / drivers / hwmon / ads7828.c

/*
 * ads7828.c - lm_sensors driver for ads7828 12-bit 8-channel ADC
 * (C) 2007 EADS Astrium
 *
 * This driver is based on the lm75 and other lm_sensors/hwmon drivers
 *
 * Written by Steve Hardy <shardy@redhat.com>
 *
 * For further information, see the Documentation/hwmon/ads7828 file.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_data/ads7828.h>
#include <linux/slab.h>

/* The ADS7828 registers */
#define ADS7828_NCH		8	/* 8 channels supported */
#define ADS7828_CMD_SD_SE	0x80	/* Single ended inputs */
#define ADS7828_CMD_PD1		0x04	/* Internal vref OFF && A/D ON */
#define ADS7828_CMD_PD3		0x0C	/* Internal vref ON && A/D ON */
#define ADS7828_INT_VREF_MV	2500	/* Internal vref is 2.5V, 2500mV */
#define ADS7828_EXT_VREF_MV_MIN	50	/* External vref min value 0.05V */
#define ADS7828_EXT_VREF_MV_MAX	5250	/* External vref max value 5.25V */

/* Client specific data */
struct ads7828_data {
	struct device *hwmon_dev;
	struct mutex update_lock;	/* Mutex protecting updates */
	unsigned long last_updated;	/* Last updated time (in jiffies) */
	u16 adc_input[ADS7828_NCH];	/* ADS7828_NCH samples */
	bool valid;			/* Validity flag */
	bool diff_input;		/* Differential input */
	bool ext_vref;			/* External voltage reference */
	unsigned int vref_mv;		/* voltage reference value */
	u8 cmd_byte;			/* Command byte without channel bits */
	unsigned int lsb_resol;		/* Resolution of the ADC sample LSB */
};

/* Command byte C2,C1,C0 - see datasheet */
static inline u8 ads7828_cmd_byte(u8 cmd, int ch)
{
	return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);
}

/* Update data for the device (all 8 channels) */
static struct ads7828_data *ads7828_update_device(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct ads7828_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
			|| !data->valid) {
		unsigned int ch;
		dev_dbg(&client->dev, "Starting ads7828 update\n");

		for (ch = 0; ch < ADS7828_NCH; ch++) {
			u8 cmd = ads7828_cmd_byte(data->cmd_byte, ch);
			data->adc_input[ch] =
				i2c_smbus_read_word_swapped(client, cmd);
		}
		data->last_updated = jiffies;
		data->valid = true;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

/* sysfs callback function */
static ssize_t ads7828_show_in(struct device *dev, struct device_attribute *da,
			       char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ads7828_data *data = ads7828_update_device(dev);
	unsigned int value = DIV_ROUND_CLOSEST(data->adc_input[attr->index] *
					       data->lsb_resol, 1000);

	return sprintf(buf, "%d\n", value);
}

static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ads7828_show_in, NULL, 0);
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1);
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2);
static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3);
static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4);
static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5);
static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6);
static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 7);

static struct attribute *ads7828_attributes[] = {
	&sensor_dev_attr_in0_input.dev_attr.attr,
	&sensor_dev_attr_in1_input.dev_attr.attr,
	&sensor_dev_attr_in2_input.dev_attr.attr,
	&sensor_dev_attr_in3_input.dev_attr.attr,
	&sensor_dev_attr_in4_input.dev_attr.attr,
	&sensor_dev_attr_in5_input.dev_attr.attr,
	&sensor_dev_attr_in6_input.dev_attr.attr,
	&sensor_dev_attr_in7_input.dev_attr.attr,
	NULL
};

static const struct attribute_group ads7828_group = {
	.attrs = ads7828_attributes,
};

static int ads7828_remove(struct i2c_client *client)
{
	struct ads7828_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &ads7828_group);

	return 0;
}

static int ads7828_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct ads7828_platform_data *pdata = client->dev.platform_data;
	struct ads7828_data *data;
	int err;

	data = devm_kzalloc(&client->dev, sizeof(struct ads7828_data),
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	if (pdata) {
		data->diff_input = pdata->diff_input;
		data->ext_vref = pdata->ext_vref;
		if (data->ext_vref)
			data->vref_mv = pdata->vref_mv;
	}

	/* Bound Vref with min/max values if it was provided */
	if (data->vref_mv)
		data->vref_mv = SENSORS_LIMIT(data->vref_mv,
					      ADS7828_EXT_VREF_MV_MIN,
					      ADS7828_EXT_VREF_MV_MAX);
	else
		data->vref_mv = ADS7828_INT_VREF_MV;

	data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096);

	data->cmd_byte = data->ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
	if (!data->diff_input)
		data->cmd_byte |= ADS7828_CMD_SD_SE;

	i2c_set_clientdata(client, data);
	mutex_init(&data->update_lock);

	err = sysfs_create_group(&client->dev.kobj, &ads7828_group);
	if (err)
		return err;

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto error;
	}

	return 0;

error:
	sysfs_remove_group(&client->dev.kobj, &ads7828_group);
	return err;
}

static const struct i2c_device_id ads7828_device_ids[] = {
	{ "ads7828", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);

static struct i2c_driver ads7828_driver = {
	.driver = {
		.name = "ads7828",
	},

	.id_table = ads7828_device_ids,
	.probe = ads7828_probe,
	.remove = ads7828_remove,
};

module_i2c_driver(ads7828_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter");
Commit	Line	Data
5812f928	1	/*
d13d6232 GR	2	* ads7828.c - lm_sensors driver for ads7828 12-bit 8-channel ADC
	3	* (C) 2007 EADS Astrium
	4	*
	5	* This driver is based on the lm75 and other lm_sensors/hwmon drivers
	6	*
	7	* Written by Steve Hardy <shardy@redhat.com>
	8	*
46d78462	9	* For further information, see the Documentation/hwmon/ads7828 file.
d13d6232 GR	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License as published by
	13	* the Free Software Foundation; either version 2 of the License, or
	14	* (at your option) any later version.
	15	*
	16	* This program is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	* GNU General Public License for more details.
	20	*
	21	* You should have received a copy of the GNU General Public License
	22	* along with this program; if not, write to the Free Software
	23	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	24	*/
5812f928	25
46d78462	26	#include <linux/err.h>
5812f928 SH	27	#include <linux/hwmon.h>
5812f928 SH	28	#include <linux/hwmon-sysfs.h>
46d78462 VD	29	#include <linux/i2c.h>
	30	#include <linux/init.h>
	31	#include <linux/jiffies.h>
	32	#include <linux/module.h>
5812f928	33	#include <linux/mutex.h>
46d78462 VD	34	#include <linux/platform_data/ads7828.h>
46d78462 VD	35	#include <linux/slab.h>
5812f928 SH	36
5812f928 SH	37	/* The ADS7828 registers */
46d78462 VD	38	#define ADS7828_NCH 8 /* 8 channels supported */
	39	#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
	40	#define ADS7828_CMD_PD1 0x04 /* Internal vref OFF && A/D ON */
	41	#define ADS7828_CMD_PD3 0x0C /* Internal vref ON && A/D ON */
	42	#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
	43	#define ADS7828_EXT_VREF_MV_MIN 50 /* External vref min value 0.05V */
	44	#define ADS7828_EXT_VREF_MV_MAX 5250 /* External vref max value 5.25V */
	45
	46	/* Client specific data */
5812f928	47	struct ads7828_data {
5812f928	48	struct device *hwmon_dev;
46d78462 VD	49	struct mutex update_lock; /* Mutex protecting updates */
	50	unsigned long last_updated; /* Last updated time (in jiffies) */
	51	u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH samples */
	52	bool valid; /* Validity flag */
	53	bool diff_input; /* Differential input */
	54	bool ext_vref; /* External voltage reference */
	55	unsigned int vref_mv; /* voltage reference value */
	56	u8 cmd_byte; /* Command byte without channel bits */
	57	unsigned int lsb_resol; /* Resolution of the ADC sample LSB */
5812f928 SH	58	};
5812f928 SH	59
46d78462 VD	60	/* Command byte C2,C1,C0 - see datasheet */
46d78462 VD	61	static inline u8 ads7828_cmd_byte(u8 cmd, int ch)
5812f928	62	{
46d78462	63	return cmd \| (((ch >> 1) \| (ch & 0x01) << 2) << 4);
5812f928 SH	64	}
	65
	66	/* Update data for the device (all 8 channels) */
	67	static struct ads7828_data ads7828_update_device(struct device dev)
	68	{
	69	struct i2c_client *client = to_i2c_client(dev);
	70	struct ads7828_data *data = i2c_get_clientdata(client);
	71
	72	mutex_lock(&data->update_lock);
	73
	74	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	75	\|\| !data->valid) {
	76	unsigned int ch;
	77	dev_dbg(&client->dev, "Starting ads7828 update\n");
	78
	79	for (ch = 0; ch < ADS7828_NCH; ch++) {
46d78462	80	u8 cmd = ads7828_cmd_byte(data->cmd_byte, ch);
90f4102c JD	81	data->adc_input[ch] =
90f4102c JD	82	i2c_smbus_read_word_swapped(client, cmd);
5812f928 SH	83	}
5812f928 SH	84	data->last_updated = jiffies;
46d78462	85	data->valid = true;
5812f928 SH	86	}
	87
	88	mutex_unlock(&data->update_lock);
	89
	90	return data;
	91	}
	92
	93	/* sysfs callback function */
46d78462 VD	94	static ssize_t ads7828_show_in(struct device dev, struct device_attribute da,
46d78462 VD	95	char *buf)
5812f928 SH	96	{
	97	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	98	struct ads7828_data *data = ads7828_update_device(dev);
46d78462 VD	99	unsigned int value = DIV_ROUND_CLOSEST(data->adc_input[attr->index] *
46d78462 VD	100	data->lsb_resol, 1000);
5812f928	101
46d78462 VD	102	return sprintf(buf, "%d\n", value);
46d78462 VD	103	}
5812f928	104
46d78462 VD	105	static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ads7828_show_in, NULL, 0);
	106	static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1);
	107	static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2);
	108	static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3);
	109	static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4);
	110	static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5);
	111	static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6);
	112	static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 7);
5812f928 SH	113
	114	static struct attribute *ads7828_attributes[] = {
	115	&sensor_dev_attr_in0_input.dev_attr.attr,
	116	&sensor_dev_attr_in1_input.dev_attr.attr,
	117	&sensor_dev_attr_in2_input.dev_attr.attr,
	118	&sensor_dev_attr_in3_input.dev_attr.attr,
	119	&sensor_dev_attr_in4_input.dev_attr.attr,
	120	&sensor_dev_attr_in5_input.dev_attr.attr,
	121	&sensor_dev_attr_in6_input.dev_attr.attr,
	122	&sensor_dev_attr_in7_input.dev_attr.attr,
	123	NULL
	124	};
	125
	126	static const struct attribute_group ads7828_group = {
	127	.attrs = ads7828_attributes,
	128	};
	129
7347cb38	130	static int ads7828_remove(struct i2c_client *client)
5812f928 SH	131	{
5812f928 SH	132	struct ads7828_data *data = i2c_get_clientdata(client);
46d78462	133
5812f928 SH	134	hwmon_device_unregister(data->hwmon_dev);
5812f928 SH	135	sysfs_remove_group(&client->dev.kobj, &ads7828_group);
5812f928	136
7347cb38 JD	137	return 0;
7347cb38 JD	138	}
5812f928	139
7347cb38 JD	140	static int ads7828_probe(struct i2c_client *client,
	141	const struct i2c_device_id *id)
	142	{
46d78462	143	struct ads7828_platform_data *pdata = client->dev.platform_data;
7347cb38 JD	144	struct ads7828_data *data;
7347cb38 JD	145	int err;
5812f928	146
34e3f7f5 GR	147	data = devm_kzalloc(&client->dev, sizeof(struct ads7828_data),
	148	GFP_KERNEL);
	149	if (!data)
	150	return -ENOMEM;
5812f928	151
46d78462 VD	152	if (pdata) {
	153	data->diff_input = pdata->diff_input;
	154	data->ext_vref = pdata->ext_vref;
	155	if (data->ext_vref)
	156	data->vref_mv = pdata->vref_mv;
	157	}
	158
	159	/* Bound Vref with min/max values if it was provided */
	160	if (data->vref_mv)
	161	data->vref_mv = SENSORS_LIMIT(data->vref_mv,
	162	ADS7828_EXT_VREF_MV_MIN,
	163	ADS7828_EXT_VREF_MV_MAX);
	164	else
	165	data->vref_mv = ADS7828_INT_VREF_MV;
	166
	167	data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096);
	168
	169	data->cmd_byte = data->ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
	170	if (!data->diff_input)
	171	data->cmd_byte \|= ADS7828_CMD_SD_SE;
	172
7347cb38	173	i2c_set_clientdata(client, data);
5812f928 SH	174	mutex_init(&data->update_lock);
5812f928 SH	175
5812f928 SH	176	err = sysfs_create_group(&client->dev.kobj, &ads7828_group);
5812f928 SH	177	if (err)
34e3f7f5	178	return err;
5812f928 SH	179
	180	data->hwmon_dev = hwmon_device_register(&client->dev);
	181	if (IS_ERR(data->hwmon_dev)) {
	182	err = PTR_ERR(data->hwmon_dev);
46d78462	183	goto error;
5812f928 SH	184	}
	185
	186	return 0;
	187
46d78462	188	error:
5812f928	189	sysfs_remove_group(&client->dev.kobj, &ads7828_group);
5812f928 SH	190	return err;
	191	}
	192
46d78462 VD	193	static const struct i2c_device_id ads7828_device_ids[] = {
	194	{ "ads7828", 0 },
	195	{ }
	196	};
	197	MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
5812f928	198
46d78462 VD	199	static struct i2c_driver ads7828_driver = {
	200	.driver = {
	201	.name = "ads7828",
	202	},
5812f928	203
46d78462 VD	204	.id_table = ads7828_device_ids,
	205	.probe = ads7828_probe,
	206	.remove = ads7828_remove,
	207	};
5812f928	208
46d78462	209	module_i2c_driver(ads7828_driver);
5812f928	210
5812f928	211	MODULE_LICENSE("GPL");
46d78462 VD	212	MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
46d78462 VD	213	MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter");