drivers/hwmon/ads7828.c - linux - Git at Google

 /*
 	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_list = normal_i2c,
 };

 /* 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);
	/*
	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_list = normal_i2c,
	};

	/* 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);