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

 /*
  * 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.rst 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/module.h>
 #include <linux/of_device.h>
 #include <linux/platform_data/ads7828.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/regulator/consumer.h>

 /* The ADS7828 registers */
 #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 regmap *regmap;
 	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);
 }

 /* sysfs callback function */
 static ssize_t ads7828_in_show(struct device *dev,
 			       struct device_attribute *da, char *buf)
 {
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 	struct ads7828_data *data = dev_get_drvdata(dev);
 	u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index);
 	unsigned int regval;
 	int err;

 	err = regmap_read(data->regmap, cmd, &regval);
 	if (err < 0)
 		return err;

 	return sprintf(buf, "%d\n",
 		       DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000));
 }

 static SENSOR_DEVICE_ATTR_RO(in0_input, ads7828_in, 0);
 static SENSOR_DEVICE_ATTR_RO(in1_input, ads7828_in, 1);
 static SENSOR_DEVICE_ATTR_RO(in2_input, ads7828_in, 2);
 static SENSOR_DEVICE_ATTR_RO(in3_input, ads7828_in, 3);
 static SENSOR_DEVICE_ATTR_RO(in4_input, ads7828_in, 4);
 static SENSOR_DEVICE_ATTR_RO(in5_input, ads7828_in, 5);
 static SENSOR_DEVICE_ATTR_RO(in6_input, ads7828_in, 6);
 static SENSOR_DEVICE_ATTR_RO(in7_input, ads7828_in, 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 const struct regmap_config ads2828_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 16,
 };

 static const struct regmap_config ads2830_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 };

 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;
 	unsigned int vref_mv = ADS7828_INT_VREF_MV;
 	unsigned int vref_uv;
 	bool diff_input = false;
 	bool ext_vref = false;
 	unsigned int regval;
 	enum ads7828_chips chip;
 	struct regulator *reg;

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

 	if (pdata) {
 		diff_input = pdata->diff_input;
 		ext_vref = pdata->ext_vref;
 		if (ext_vref && pdata->vref_mv)
 			vref_mv = pdata->vref_mv;
 	} else if (dev->of_node) {
 		diff_input = of_property_read_bool(dev->of_node,
 						   "ti,differential-input");
 		reg = devm_regulator_get_optional(dev, "vref");
 		if (!IS_ERR(reg)) {
 			vref_uv = regulator_get_voltage(reg);
 			vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
 			if (vref_mv < ADS7828_EXT_VREF_MV_MIN ||
 			    vref_mv > ADS7828_EXT_VREF_MV_MAX)
 				return -EINVAL;
 			ext_vref = true;
 		}
 	}

 	if (client->dev.of_node)
 		chip = (enum ads7828_chips)
 			of_device_get_match_data(&client->dev);
 	else
 		chip = id->driver_data;

 	/* Bound Vref with min/max values */
 	vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,
 			    ADS7828_EXT_VREF_MV_MAX);

 	/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
 	if (chip == ads7828) {
 		data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);
 		data->regmap = devm_regmap_init_i2c(client,
 						    &ads2828_regmap_config);
 	} else {
 		data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);
 		data->regmap = devm_regmap_init_i2c(client,
 						    &ads2830_regmap_config);
 	}

 	if (IS_ERR(data->regmap))
 		return PTR_ERR(data->regmap);

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

 	/*
 	 * Datasheet specifies internal reference voltage is disabled by
 	 * default. The internal reference voltage needs to be enabled and
 	 * voltage needs to settle before getting valid ADC data. So perform a
 	 * dummy read to enable the internal reference voltage.
 	 */
 	if (!ext_vref)
 		regmap_read(data->regmap, data->cmd_byte, &regval);

 	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 const struct of_device_id __maybe_unused ads7828_of_match[] = {
 	{
 		.compatible = "ti,ads7828",
 		.data = (void *)ads7828
 	},
 	{
 		.compatible = "ti,ads7830",
 		.data = (void *)ads7830
 	},
 	{ },
 };
 MODULE_DEVICE_TABLE(of, ads7828_of_match);

 static struct i2c_driver ads7828_driver = {
 	.driver = {
 		.name = "ads7828",
 		.of_match_table = of_match_ptr(ads7828_of_match),
 	},

 	.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.rst 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/module.h>
	#include <linux/of_device.h>
	#include <linux/platform_data/ads7828.h>
	#include <linux/regmap.h>
	#include <linux/slab.h>
	#include <linux/regulator/consumer.h>

	/* The ADS7828 registers */
	#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 regmap *regmap;
	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);
	}

	/* sysfs callback function */
	static ssize_t ads7828_in_show(struct device *dev,
	struct device_attribute da, char buf)
	{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ads7828_data *data = dev_get_drvdata(dev);
	u8 cmd = ads7828_cmd_byte(data->cmd_byte, attr->index);
	unsigned int regval;
	int err;

	err = regmap_read(data->regmap, cmd, &regval);
	if (err < 0)
	return err;

	return sprintf(buf, "%d\n",
	DIV_ROUND_CLOSEST(regval * data->lsb_resol, 1000));
	}

	static SENSOR_DEVICE_ATTR_RO(in0_input, ads7828_in, 0);
	static SENSOR_DEVICE_ATTR_RO(in1_input, ads7828_in, 1);
	static SENSOR_DEVICE_ATTR_RO(in2_input, ads7828_in, 2);
	static SENSOR_DEVICE_ATTR_RO(in3_input, ads7828_in, 3);
	static SENSOR_DEVICE_ATTR_RO(in4_input, ads7828_in, 4);
	static SENSOR_DEVICE_ATTR_RO(in5_input, ads7828_in, 5);
	static SENSOR_DEVICE_ATTR_RO(in6_input, ads7828_in, 6);
	static SENSOR_DEVICE_ATTR_RO(in7_input, ads7828_in, 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 const struct regmap_config ads2828_regmap_config = {
	.reg_bits = 8,
	.val_bits = 16,
	};

	static const struct regmap_config ads2830_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	};

	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;
	unsigned int vref_mv = ADS7828_INT_VREF_MV;
	unsigned int vref_uv;
	bool diff_input = false;
	bool ext_vref = false;
	unsigned int regval;
	enum ads7828_chips chip;
	struct regulator *reg;

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

	if (pdata) {
	diff_input = pdata->diff_input;
	ext_vref = pdata->ext_vref;
	if (ext_vref && pdata->vref_mv)
	vref_mv = pdata->vref_mv;
	} else if (dev->of_node) {
	diff_input = of_property_read_bool(dev->of_node,
	"ti,differential-input");
	reg = devm_regulator_get_optional(dev, "vref");
	if (!IS_ERR(reg)) {
	vref_uv = regulator_get_voltage(reg);
	vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
	if (vref_mv < ADS7828_EXT_VREF_MV_MIN \|\|
	vref_mv > ADS7828_EXT_VREF_MV_MAX)
	return -EINVAL;
	ext_vref = true;
	}
	}

	if (client->dev.of_node)
	chip = (enum ads7828_chips)
	of_device_get_match_data(&client->dev);
	else
	chip = id->driver_data;

	/* Bound Vref with min/max values */
	vref_mv = clamp_val(vref_mv, ADS7828_EXT_VREF_MV_MIN,
	ADS7828_EXT_VREF_MV_MAX);

	/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
	if (chip == ads7828) {
	data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 4096);
	data->regmap = devm_regmap_init_i2c(client,
	&ads2828_regmap_config);
	} else {
	data->lsb_resol = DIV_ROUND_CLOSEST(vref_mv * 1000, 256);
	data->regmap = devm_regmap_init_i2c(client,
	&ads2830_regmap_config);
	}

	if (IS_ERR(data->regmap))
	return PTR_ERR(data->regmap);

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

	/*
	* Datasheet specifies internal reference voltage is disabled by
	* default. The internal reference voltage needs to be enabled and
	* voltage needs to settle before getting valid ADC data. So perform a
	* dummy read to enable the internal reference voltage.
	*/
	if (!ext_vref)
	regmap_read(data->regmap, data->cmd_byte, &regval);

	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 const struct of_device_id __maybe_unused ads7828_of_match[] = {
	{
	.compatible = "ti,ads7828",
	.data = (void *)ads7828
	},
	{
	.compatible = "ti,ads7830",
	.data = (void *)ads7830
	},
	{ },
	};
	MODULE_DEVICE_TABLE(of, ads7828_of_match);

	static struct i2c_driver ads7828_driver = {
	.driver = {
	.name = "ads7828",
	.of_match_table = of_match_ptr(ads7828_of_match),
	},

	.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");