drivers/hwmon/ads7828.c - kernel/msm-4.9 - Gitiles

 /*
  * ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles
  * (C) 2007 EADS Astrium
  *
  * This driver is based on the lm75 and other lm_sensors/hwmon drivers
  *
  * Written by Steve Hardy <shardy@redhat.com>
  *
  * ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.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 */

 /* List of supported devices */
 enum ads7828_chips { ads7828, ads7830 };

 /* Client specific data */
 struct ads7828_data {
 	struct i2c_client *client;
 	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 */
 	s32 (*read_channel)(const struct i2c_client *client, u8 command);
 };

 /* 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 ads7828_data *data = dev_get_drvdata(dev);
 	struct i2c_client *client = data->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] = data->read_channel(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_attrs[] = {
 	&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
 };

 ATTRIBUTE_GROUPS(ads7828);

 static int ads7828_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
 	struct ads7828_platform_data *pdata = dev_get_platdata(dev);
 	struct ads7828_data *data;
 	struct device *hwmon_dev;

 	data = devm_kzalloc(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 = clamp_val(data->vref_mv,
 					  ADS7828_EXT_VREF_MV_MIN,
 					  ADS7828_EXT_VREF_MV_MAX);
 	else
 		data->vref_mv = ADS7828_INT_VREF_MV;

 	/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
 	if (id->driver_data == ads7828) {
 		data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096);
 		data->read_channel = i2c_smbus_read_word_swapped;
 	} else {
 		data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 256);
 		data->read_channel = i2c_smbus_read_byte_data;
 	}

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

 	data->client = client;
 	mutex_init(&data->update_lock);

 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 							   data,
 							   ads7828_groups);
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }

 static const struct i2c_device_id ads7828_device_ids[] = {
 	{ "ads7828", ads7828 },
 	{ "ads7830", ads7830 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);

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

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

 module_i2c_driver(ads7828_driver);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
 MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
	/*
	* ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles
	* (C) 2007 EADS Astrium
	*
	* This driver is based on the lm75 and other lm_sensors/hwmon drivers
	*
	* Written by Steve Hardy <shardy@redhat.com>
	*
	* ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.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 */

	/* List of supported devices */
	enum ads7828_chips { ads7828, ads7830 };

	/* Client specific data */
	struct ads7828_data {
	struct i2c_client *client;
	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 */
	s32 (read_channel)(const struct i2c_client client, u8 command);
	};

	/* 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 ads7828_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->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] = data->read_channel(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_attrs[] = {
	&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
	};

	ATTRIBUTE_GROUPS(ads7828);

	static int ads7828_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct device *dev = &client->dev;
	struct ads7828_platform_data *pdata = dev_get_platdata(dev);
	struct ads7828_data *data;
	struct device *hwmon_dev;

	data = devm_kzalloc(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 = clamp_val(data->vref_mv,
	ADS7828_EXT_VREF_MV_MIN,
	ADS7828_EXT_VREF_MV_MAX);
	else
	data->vref_mv = ADS7828_INT_VREF_MV;

	/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
	if (id->driver_data == ads7828) {
	data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096);
	data->read_channel = i2c_smbus_read_word_swapped;
	} else {
	data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 256);
	data->read_channel = i2c_smbus_read_byte_data;
	}

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

	data->client = client;
	mutex_init(&data->update_lock);

	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
	data,
	ads7828_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
	}

	static const struct i2c_device_id ads7828_device_ids[] = {
	{ "ads7828", ads7828 },
	{ "ads7830", ads7830 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);

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

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

	module_i2c_driver(ads7828_driver);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
	MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");