[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 <steve@linuxrealtime.co.uk>

	Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads7828.pdf

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

/* The ADS7828 registers */
#define ADS7828_NCH 8 /* 8 channels of 12-bit A-D supported */
#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
#define ADS7828_CMD_SD_DIFF 0x00 /* Differential inputs */
#define ADS7828_CMD_PD0 0x0 /* Power Down between A-D conversions */
#define ADS7828_CMD_PD1 0x04 /* Internal ref OFF && A-D ON */
#define ADS7828_CMD_PD2 0x08 /* Internal ref ON && A-D OFF */
#define ADS7828_CMD_PD3 0x0C /* Internal ref ON && A-D ON */
#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */

/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
	I2C_CLIENT_END };

/* Insmod parameters */
I2C_CLIENT_INSMOD_1(ads7828);

/* Other module parameters */
static int se_input = 1; /* Default is SE, 0 == diff */
static int int_vref = 1; /* Default is internal ref ON */
static int vref_mv = ADS7828_INT_VREF_MV; /* set if vref != 2.5V */
module_param(se_input, bool, S_IRUGO);
module_param(int_vref, bool, S_IRUGO);
module_param(vref_mv, int, S_IRUGO);

/* Global Variables */
static u8 ads7828_cmd_byte; /* cmd byte without channel bits */
static unsigned int ads7828_lsb_resol; /* resolution of the ADC sample lsb */

/* Each client has this additional data */
struct ads7828_data {
	struct device *hwmon_dev;
	struct mutex update_lock; /* mutex protect updates */
	char valid; /* !=0 if following fields are valid */
	unsigned long last_updated; /* In jiffies */
	u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH 12-bit samples */
};

/* Function declaration - necessary due to function dependencies */
static int ads7828_detect(struct i2c_client *client,
			  struct i2c_board_info *info);
static int ads7828_probe(struct i2c_client *client,
			 const struct i2c_device_id *id);

/* The ADS7828 returns the 12-bit sample in two bytes,
	these are read as a word then byte-swapped */
static u16 ads7828_read_value(struct i2c_client *client, u8 reg)
{
	return swab16(i2c_smbus_read_word_data(client, reg));
}

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

/* 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 = channel_cmd_byte(ch);
			data->adc_input[ch] = ads7828_read_value(client, cmd);
		}
		data->last_updated = jiffies;
		data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

/* sysfs callback function */
static ssize_t 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);
	/* Print value (in mV as specified in sysfs-interface documentation) */
	return sprintf(buf, "%d\n", (data->adc_input[attr->index] *
		ads7828_lsb_resol)/1000);
}

#define in_reg(offset)\
static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\
	NULL, offset)

in_reg(0);
in_reg(1);
in_reg(2);
in_reg(3);
in_reg(4);
in_reg(5);
in_reg(6);
in_reg(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);
	kfree(i2c_get_clientdata(client));
	return 0;
}

static const struct i2c_device_id ads7828_id[] = {
	{ "ads7828", ads7828 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ads7828_id);

/* This is the driver that will be inserted */
static struct i2c_driver ads7828_driver = {
	.class = I2C_CLASS_HWMON,
	.driver = {
		.name = "ads7828",
	},
	.probe = ads7828_probe,
	.remove = ads7828_remove,
	.id_table = ads7828_id,
	.detect = ads7828_detect,
	.address_data = &addr_data,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int ads7828_detect(struct i2c_client *client,
			  struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = client->adapter;
	int ch;

	/* Check we have a valid client */
	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA))
		return -ENODEV;

	/* Now, we do the remaining detection. There is no identification
	dedicated register so attempt to sanity check using knowledge of
	the chip
	- Read from the 8 channel addresses
	- Check the top 4 bits of each result are not set (12 data bits)
	*/
	for (ch = 0; ch < ADS7828_NCH; ch++) {
		u16 in_data;
		u8 cmd = channel_cmd_byte(ch);
		in_data = ads7828_read_value(client, cmd);
		if (in_data & 0xF000) {
			pr_debug("%s : Doesn't look like an ads7828 device\n",
				 __func__);
			return -ENODEV;
		}
	}

	strlcpy(info->type, "ads7828", I2C_NAME_SIZE);

	return 0;
}

static int ads7828_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct ads7828_data *data;
	int err;

	data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL);
	if (!data) {
		err = -ENOMEM;
		goto exit;
	}

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

	/* Register sysfs hooks */
	err = sysfs_create_group(&client->dev.kobj, &ads7828_group);
	if (err)
		goto exit_free;

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

	return 0;

exit_remove:
	sysfs_remove_group(&client->dev.kobj, &ads7828_group);
exit_free:
	kfree(data);
exit:
	return err;
}

static int __init sensors_ads7828_init(void)
{
	/* Initialize the command byte according to module parameters */
	ads7828_cmd_byte = se_input ?
		ADS7828_CMD_SD_SE : ADS7828_CMD_SD_DIFF;
	ads7828_cmd_byte |= int_vref ?
		ADS7828_CMD_PD3 : ADS7828_CMD_PD1;

	/* Calculate the LSB resolution */
	ads7828_lsb_resol = (vref_mv*1000)/4096;

	return i2c_add_driver(&ads7828_driver);
}

static void __exit sensors_ads7828_exit(void)
{
	i2c_del_driver(&ads7828_driver);
}

MODULE_AUTHOR("Steve Hardy <steve@linuxrealtime.co.uk>");
MODULE_DESCRIPTION("ADS7828 driver");
MODULE_LICENSE("GPL");

module_init(sensors_ads7828_init);
module_exit(sensors_ads7828_exit);
Commit	Line	Data
5812f928 SH	1	/*
	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 <steve@linuxrealtime.co.uk>
	8
	9	Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads7828.pdf
	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	*/
	25
	26	#include <linux/module.h>
	27	#include <linux/init.h>
	28	#include <linux/slab.h>
	29	#include <linux/jiffies.h>
	30	#include <linux/i2c.h>
	31	#include <linux/hwmon.h>
	32	#include <linux/hwmon-sysfs.h>
	33	#include <linux/err.h>
	34	#include <linux/mutex.h>
	35
	36	/* The ADS7828 registers */
	37	#define ADS7828_NCH 8 /* 8 channels of 12-bit A-D supported */
	38	#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
	39	#define ADS7828_CMD_SD_DIFF 0x00 /* Differential inputs */
	40	#define ADS7828_CMD_PD0 0x0 /* Power Down between A-D conversions */
	41	#define ADS7828_CMD_PD1 0x04 /* Internal ref OFF && A-D ON */
	42	#define ADS7828_CMD_PD2 0x08 /* Internal ref ON && A-D OFF */
	43	#define ADS7828_CMD_PD3 0x0C /* Internal ref ON && A-D ON */
	44	#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
	45
	46	/* Addresses to scan */
25e9c86d	47	static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
5812f928 SH	48	I2C_CLIENT_END };
	49
	50	/* Insmod parameters */
	51	I2C_CLIENT_INSMOD_1(ads7828);
	52
	53	/* Other module parameters */
	54	static int se_input = 1; /* Default is SE, 0 == diff */
	55	static int int_vref = 1; /* Default is internal ref ON */
	56	static int vref_mv = ADS7828_INT_VREF_MV; /* set if vref != 2.5V */
	57	module_param(se_input, bool, S_IRUGO);
	58	module_param(int_vref, bool, S_IRUGO);
	59	module_param(vref_mv, int, S_IRUGO);
	60
	61	/* Global Variables */
	62	static u8 ads7828_cmd_byte; /* cmd byte without channel bits */
	63	static unsigned int ads7828_lsb_resol; /* resolution of the ADC sample lsb */
	64
	65	/* Each client has this additional data */
	66	struct ads7828_data {
5812f928 SH	67	struct device *hwmon_dev;
	68	struct mutex update_lock; /* mutex protect updates */
	69	char valid; /* !=0 if following fields are valid */
	70	unsigned long last_updated; /* In jiffies */
	71	u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH 12-bit samples */
	72	};
	73
	74	/* Function declaration - necessary due to function dependencies */
310ec792	75	static int ads7828_detect(struct i2c_client *client,
7347cb38 JD	76	struct i2c_board_info *info);
	77	static int ads7828_probe(struct i2c_client *client,
	78	const struct i2c_device_id *id);
5812f928 SH	79
	80	/* The ADS7828 returns the 12-bit sample in two bytes,
	81	these are read as a word then byte-swapped */
	82	static u16 ads7828_read_value(struct i2c_client *client, u8 reg)
	83	{
	84	return swab16(i2c_smbus_read_word_data(client, reg));
	85	}
	86
	87	static inline u8 channel_cmd_byte(int ch)
	88	{
	89	/* cmd byte C2,C1,C0 - see datasheet */
	90	u8 cmd = (((ch>>1) \| (ch&0x01)<<2)<<4);
	91	cmd \|= ads7828_cmd_byte;
	92	return cmd;
	93	}
	94
	95	/* Update data for the device (all 8 channels) */
	96	static struct ads7828_data ads7828_update_device(struct device dev)
	97	{
	98	struct i2c_client *client = to_i2c_client(dev);
	99	struct ads7828_data *data = i2c_get_clientdata(client);
	100
	101	mutex_lock(&data->update_lock);
	102
	103	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
	104	\|\| !data->valid) {
	105	unsigned int ch;
	106	dev_dbg(&client->dev, "Starting ads7828 update\n");
	107
	108	for (ch = 0; ch < ADS7828_NCH; ch++) {
	109	u8 cmd = channel_cmd_byte(ch);
	110	data->adc_input[ch] = ads7828_read_value(client, cmd);
	111	}
	112	data->last_updated = jiffies;
	113	data->valid = 1;
	114	}
	115
	116	mutex_unlock(&data->update_lock);
	117
	118	return data;
	119	}
	120
	121	/* sysfs callback function */
	122	static ssize_t show_in(struct device dev, struct device_attribute da,
	123	char *buf)
	124	{
	125	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	126	struct ads7828_data *data = ads7828_update_device(dev);
	127	/* Print value (in mV as specified in sysfs-interface documentation) */
	128	return sprintf(buf, "%d\n", (data->adc_input[attr->index] *
	129	ads7828_lsb_resol)/1000);
	130	}
	131
	132	#define in_reg(offset)\
	133	static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\
	134	NULL, offset)
	135
	136	in_reg(0);
	137	in_reg(1);
	138	in_reg(2);
	139	in_reg(3);
	140	in_reg(4);
	141	in_reg(5);
	142	in_reg(6);
143	in_reg(7);
144
145	static struct attribute *ads7828_attributes[] = {
146	&sensor_dev_attr_in0_input.dev_attr.attr,
147	&sensor_dev_attr_in1_input.dev_attr.attr,
148	&sensor_dev_attr_in2_input.dev_attr.attr,
149	&sensor_dev_attr_in3_input.dev_attr.attr,
150	&sensor_dev_attr_in4_input.dev_attr.attr,
151	&sensor_dev_attr_in5_input.dev_attr.attr,
152	&sensor_dev_attr_in6_input.dev_attr.attr,
153	&sensor_dev_attr_in7_input.dev_attr.attr,
154	NULL
155	};
156
157	static const struct attribute_group ads7828_group = {
158	.attrs = ads7828_attributes,
159	};
160
7347cb38	161	static int ads7828_remove(struct i2c_client *client)
5812f928 SH	162	{
	163	struct ads7828_data *data = i2c_get_clientdata(client);
	164	hwmon_device_unregister(data->hwmon_dev);
	165	sysfs_remove_group(&client->dev.kobj, &ads7828_group);
5812f928 SH	166	kfree(i2c_get_clientdata(client));
	167	return 0;
	168	}
	169
7347cb38 JD	170	static const struct i2c_device_id ads7828_id[] = {
	171	{ "ads7828", ads7828 },
	172	{ }
	173	};
	174	MODULE_DEVICE_TABLE(i2c, ads7828_id);
	175
5812f928 SH	176	/* This is the driver that will be inserted */
5812f928 SH	177	static struct i2c_driver ads7828_driver = {
7347cb38	178	.class = I2C_CLASS_HWMON,
5812f928 SH	179	.driver = {
	180	.name = "ads7828",
	181	},
7347cb38 JD	182	.probe = ads7828_probe,
	183	.remove = ads7828_remove,
	184	.id_table = ads7828_id,
	185	.detect = ads7828_detect,
	186	.address_data = &addr_data,
5812f928 SH	187	};
5812f928 SH	188
7347cb38	189	/* Return 0 if detection is successful, -ENODEV otherwise */
310ec792	190	static int ads7828_detect(struct i2c_client *client,
7347cb38	191	struct i2c_board_info *info)
5812f928	192	{
7347cb38	193	struct i2c_adapter *adapter = client->adapter;
52df6440	194	int ch;
5812f928 SH	195
	196	/* Check we have a valid client */
	197	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA))
7347cb38	198	return -ENODEV;
5812f928 SH	199
	200	/* Now, we do the remaining detection. There is no identification
	201	dedicated register so attempt to sanity check using knowledge of
	202	the chip
	203	- Read from the 8 channel addresses
	204	- Check the top 4 bits of each result are not set (12 data bits)
	205	*/
52df6440 JD	206	for (ch = 0; ch < ADS7828_NCH; ch++) {
	207	u16 in_data;
	208	u8 cmd = channel_cmd_byte(ch);
	209	in_data = ads7828_read_value(client, cmd);
	210	if (in_data & 0xF000) {
	211	pr_debug("%s : Doesn't look like an ads7828 device\n",
	212	__func__);
	213	return -ENODEV;
5812f928 SH	214	}
5812f928 SH	215	}
52df6440	216
7347cb38	217	strlcpy(info->type, "ads7828", I2C_NAME_SIZE);
5812f928	218
7347cb38 JD	219	return 0;
7347cb38 JD	220	}
5812f928	221
7347cb38 JD	222	static int ads7828_probe(struct i2c_client *client,
	223	const struct i2c_device_id *id)
	224	{
	225	struct ads7828_data *data;
	226	int err;
5812f928	227
7347cb38 JD	228	data = kzalloc(sizeof(struct ads7828_data), GFP_KERNEL);
	229	if (!data) {
	230	err = -ENOMEM;
	231	goto exit;
	232	}
5812f928	233
7347cb38	234	i2c_set_clientdata(client, data);
5812f928 SH	235	mutex_init(&data->update_lock);
5812f928 SH	236
5812f928 SH	237	/* Register sysfs hooks */
	238	err = sysfs_create_group(&client->dev.kobj, &ads7828_group);
	239	if (err)
7347cb38	240	goto exit_free;
5812f928 SH	241
	242	data->hwmon_dev = hwmon_device_register(&client->dev);
	243	if (IS_ERR(data->hwmon_dev)) {
	244	err = PTR_ERR(data->hwmon_dev);
	245	goto exit_remove;
	246	}
	247
	248	return 0;
	249
	250	exit_remove:
	251	sysfs_remove_group(&client->dev.kobj, &ads7828_group);
5812f928 SH	252	exit_free:
	253	kfree(data);
	254	exit:
	255	return err;
	256	}
	257
	258	static int __init sensors_ads7828_init(void)
	259	{
	260	/* Initialize the command byte according to module parameters */
	261	ads7828_cmd_byte = se_input ?
	262	ADS7828_CMD_SD_SE : ADS7828_CMD_SD_DIFF;
	263	ads7828_cmd_byte \|= int_vref ?
	264	ADS7828_CMD_PD3 : ADS7828_CMD_PD1;
	265
	266	/* Calculate the LSB resolution */
	267	ads7828_lsb_resol = (vref_mv*1000)/4096;
	268
	269	return i2c_add_driver(&ads7828_driver);
	270	}
	271
	272	static void __exit sensors_ads7828_exit(void)
	273	{
	274	i2c_del_driver(&ads7828_driver);
	275	}
	276
	277	MODULE_AUTHOR("Steve Hardy <steve@linuxrealtime.co.uk>");
	278	MODULE_DESCRIPTION("ADS7828 driver");
	279	MODULE_LICENSE("GPL");
	280
	281	module_init(sensors_ads7828_init);
	282	module_exit(sensors_ads7828_exit);