drivers/hwmon/ltc4261.c - kernel/msm-4.19 - Gitiles

 /*
  * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller
  *
  * Copyright (C) 2010 Ericsson AB.
  *
  * Derived from:
  *
  *  Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
  *  Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
  *
  * Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.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/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>

 /* chip registers */
 #define LTC4261_STATUS	0x00	/* readonly */
 #define LTC4261_FAULT	0x01
 #define LTC4261_ALERT	0x02
 #define LTC4261_CONTROL	0x03
 #define LTC4261_SENSE_H	0x04
 #define LTC4261_SENSE_L	0x05
 #define LTC4261_ADIN2_H	0x06
 #define LTC4261_ADIN2_L	0x07
 #define LTC4261_ADIN_H	0x08
 #define LTC4261_ADIN_L	0x09

 /*
  * Fault register bits
  */
 #define FAULT_OV	(1<<0)
 #define FAULT_UV	(1<<1)
 #define FAULT_OC	(1<<2)

 struct ltc4261_data {
 	struct device *hwmon_dev;

 	struct mutex update_lock;
 	bool valid;
 	unsigned long last_updated;	/* in jiffies */

 	/* Registers */
 	u8 regs[10];
 };

 static struct ltc4261_data *ltc4261_update_device(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct ltc4261_data *data = i2c_get_clientdata(client);
 	struct ltc4261_data *ret = data;

 	mutex_lock(&data->update_lock);

 	if (time_after(jiffies, data->last_updated + HZ / 4) || !data->valid) {
 		int i;

 		/* Read registers -- 0x00 to 0x09 */
 		for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
 			int val;

 			val = i2c_smbus_read_byte_data(client, i);
 			if (unlikely(val < 0)) {
 				dev_dbg(dev,
 					"Failed to read ADC value: error %d\n",
 					val);
 				ret = ERR_PTR(val);
 				data->valid = 0;
 				goto abort;
 			}
 			data->regs[i] = val;
 		}
 		data->last_updated = jiffies;
 		data->valid = 1;
 	}
 abort:
 	mutex_unlock(&data->update_lock);
 	return ret;
 }

 /* Return the voltage from the given register in mV or mA */
 static int ltc4261_get_value(struct ltc4261_data *data, u8 reg)
 {
 	u32 val;

 	val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6);

 	switch (reg) {
 	case LTC4261_ADIN_H:
 	case LTC4261_ADIN2_H:
 		/* 2.5mV resolution. Convert to mV. */
 		val = val * 25 / 10;
 		break;
 	case LTC4261_SENSE_H:
 		/*
 		 * 62.5uV resolution. Convert to current as measured with
 		 * an 1 mOhm sense resistor, in mA. If a different sense
 		 * resistor is installed, calculate the actual current by
 		 * dividing the reported current by the sense resistor value
 		 * in mOhm.
 		 */
 		val = val * 625 / 10;
 		break;
 	default:
 		/* If we get here, the developer messed up */
 		WARN_ON_ONCE(1);
 		val = 0;
 		break;
 	}

 	return val;
 }

 static ssize_t ltc4261_show_value(struct device *dev,
 				  struct device_attribute *da, char *buf)
 {
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 	struct ltc4261_data *data = ltc4261_update_device(dev);
 	int value;

 	if (IS_ERR(data))
 		return PTR_ERR(data);

 	value = ltc4261_get_value(data, attr->index);
 	return snprintf(buf, PAGE_SIZE, "%d\n", value);
 }

 static ssize_t ltc4261_show_bool(struct device *dev,
 				 struct device_attribute *da, char *buf)
 {
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 	struct i2c_client *client = to_i2c_client(dev);
 	struct ltc4261_data *data = ltc4261_update_device(dev);
 	u8 fault;

 	if (IS_ERR(data))
 		return PTR_ERR(data);

 	fault = data->regs[LTC4261_FAULT] & attr->index;
 	if (fault)		/* Clear reported faults in chip register */
 		i2c_smbus_write_byte_data(client, LTC4261_FAULT, ~fault);

 	return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0);
 }

 /*
  * These macros are used below in constructing device attribute objects
  * for use with sysfs_create_group() to make a sysfs device file
  * for each register.
  */

 #define LTC4261_VALUE(name, ltc4261_cmd_idx) \
 	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 	ltc4261_show_value, NULL, ltc4261_cmd_idx)

 #define LTC4261_BOOL(name, mask) \
 	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
 	ltc4261_show_bool, NULL, (mask))

 /*
  * Input voltages.
  */
 LTC4261_VALUE(in1_input, LTC4261_ADIN_H);
 LTC4261_VALUE(in2_input, LTC4261_ADIN2_H);

 /*
  * Voltage alarms. The chip has only one set of voltage alarm status bits,
  * triggered by input voltage alarms. In many designs, those alarms are
  * associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin
  * to the OV pin. ADIN2 is, however, not available on all chip variants.
  * To ensure that the alarm condition is reported to the user, report it
  * with both voltage sensors.
  */
 LTC4261_BOOL(in1_min_alarm, FAULT_UV);
 LTC4261_BOOL(in1_max_alarm, FAULT_OV);
 LTC4261_BOOL(in2_min_alarm, FAULT_UV);
 LTC4261_BOOL(in2_max_alarm, FAULT_OV);

 /* Currents (via sense resistor) */
 LTC4261_VALUE(curr1_input, LTC4261_SENSE_H);

 /* Overcurrent alarm */
 LTC4261_BOOL(curr1_max_alarm, FAULT_OC);

 static struct attribute *ltc4261_attributes[] = {
 	&sensor_dev_attr_in1_input.dev_attr.attr,
 	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
 	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
 	&sensor_dev_attr_in2_input.dev_attr.attr,
 	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
 	&sensor_dev_attr_in2_max_alarm.dev_attr.attr,

 	&sensor_dev_attr_curr1_input.dev_attr.attr,
 	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,

 	NULL,
 };

 static const struct attribute_group ltc4261_group = {
 	.attrs = ltc4261_attributes,
 };

 static int ltc4261_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct i2c_adapter *adapter = client->adapter;
 	struct ltc4261_data *data;
 	int ret;

 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 		return -ENODEV;

 	if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) {
 		dev_err(&client->dev, "Failed to read status register\n");
 		return -ENODEV;
 	}

 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data) {
 		ret = -ENOMEM;
 		goto out_kzalloc;
 	}

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

 	/* Clear faults */
 	i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00);

 	/* Register sysfs hooks */
 	ret = sysfs_create_group(&client->dev.kobj, &ltc4261_group);
 	if (ret)
 		goto out_sysfs_create_group;

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

 	return 0;

 out_hwmon_device_register:
 	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);
 out_sysfs_create_group:
 	kfree(data);
 out_kzalloc:
 	return ret;
 }

 static int ltc4261_remove(struct i2c_client *client)
 {
 	struct ltc4261_data *data = i2c_get_clientdata(client);

 	hwmon_device_unregister(data->hwmon_dev);
 	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);

 	kfree(data);

 	return 0;
 }

 static const struct i2c_device_id ltc4261_id[] = {
 	{"ltc4261", 0},
 	{}
 };

 MODULE_DEVICE_TABLE(i2c, ltc4261_id);

 /* This is the driver that will be inserted */
 static struct i2c_driver ltc4261_driver = {
 	.driver = {
 		   .name = "ltc4261",
 		   },
 	.probe = ltc4261_probe,
 	.remove = ltc4261_remove,
 	.id_table = ltc4261_id,
 };

 module_i2c_driver(ltc4261_driver);

 MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
 MODULE_DESCRIPTION("LTC4261 driver");
 MODULE_LICENSE("GPL");
	/*
	* Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller
	*
	* Copyright (C) 2010 Ericsson AB.
	*
	* Derived from:
	*
	* Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
	* Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
	*
	* Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.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/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/err.h>
	#include <linux/slab.h>
	#include <linux/i2c.h>
	#include <linux/hwmon.h>
	#include <linux/hwmon-sysfs.h>

	/* chip registers */
	#define LTC4261_STATUS 0x00 /* readonly */
	#define LTC4261_FAULT 0x01
	#define LTC4261_ALERT 0x02
	#define LTC4261_CONTROL 0x03
	#define LTC4261_SENSE_H 0x04
	#define LTC4261_SENSE_L 0x05
	#define LTC4261_ADIN2_H 0x06
	#define LTC4261_ADIN2_L 0x07
	#define LTC4261_ADIN_H 0x08
	#define LTC4261_ADIN_L 0x09

	/*
	* Fault register bits
	*/
	#define FAULT_OV (1<<0)
	#define FAULT_UV (1<<1)
	#define FAULT_OC (1<<2)

	struct ltc4261_data {
	struct device *hwmon_dev;

	struct mutex update_lock;
	bool valid;
	unsigned long last_updated; /* in jiffies */

	/* Registers */
	u8 regs[10];
	};

	static struct ltc4261_data ltc4261_update_device(struct device dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct ltc4261_data *data = i2c_get_clientdata(client);
	struct ltc4261_data *ret = data;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ / 4) \|\| !data->valid) {
	int i;

	/* Read registers -- 0x00 to 0x09 */
	for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
	int val;

	val = i2c_smbus_read_byte_data(client, i);
	if (unlikely(val < 0)) {
	dev_dbg(dev,
	"Failed to read ADC value: error %d\n",
	val);
	ret = ERR_PTR(val);
	data->valid = 0;
	goto abort;
	}
	data->regs[i] = val;
	}
	data->last_updated = jiffies;
	data->valid = 1;
	}
	abort:
	mutex_unlock(&data->update_lock);
	return ret;
	}

	/* Return the voltage from the given register in mV or mA */
	static int ltc4261_get_value(struct ltc4261_data *data, u8 reg)
	{
	u32 val;

	val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6);

	switch (reg) {
	case LTC4261_ADIN_H:
	case LTC4261_ADIN2_H:
	/* 2.5mV resolution. Convert to mV. */
	val = val * 25 / 10;
	break;
	case LTC4261_SENSE_H:
	/*
	* 62.5uV resolution. Convert to current as measured with
	* an 1 mOhm sense resistor, in mA. If a different sense
	* resistor is installed, calculate the actual current by
	* dividing the reported current by the sense resistor value
	* in mOhm.
	*/
	val = val * 625 / 10;
	break;
	default:
	/* If we get here, the developer messed up */
	WARN_ON_ONCE(1);
	val = 0;
	break;
	}

	return val;
	}

	static ssize_t ltc4261_show_value(struct device *dev,
	struct device_attribute da, char buf)
	{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ltc4261_data *data = ltc4261_update_device(dev);
	int value;

	if (IS_ERR(data))
	return PTR_ERR(data);

	value = ltc4261_get_value(data, attr->index);
	return snprintf(buf, PAGE_SIZE, "%d\n", value);
	}

	static ssize_t ltc4261_show_bool(struct device *dev,
	struct device_attribute da, char buf)
	{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct i2c_client *client = to_i2c_client(dev);
	struct ltc4261_data *data = ltc4261_update_device(dev);
	u8 fault;

	if (IS_ERR(data))
	return PTR_ERR(data);

	fault = data->regs[LTC4261_FAULT] & attr->index;
	if (fault) /* Clear reported faults in chip register */
	i2c_smbus_write_byte_data(client, LTC4261_FAULT, ~fault);

	return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0);
	}

	/*
	* These macros are used below in constructing device attribute objects
	* for use with sysfs_create_group() to make a sysfs device file
	* for each register.
	*/

	#define LTC4261_VALUE(name, ltc4261_cmd_idx) \
	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	ltc4261_show_value, NULL, ltc4261_cmd_idx)

	#define LTC4261_BOOL(name, mask) \
	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
	ltc4261_show_bool, NULL, (mask))

	/*
	* Input voltages.
	*/
	LTC4261_VALUE(in1_input, LTC4261_ADIN_H);
	LTC4261_VALUE(in2_input, LTC4261_ADIN2_H);

	/*
	* Voltage alarms. The chip has only one set of voltage alarm status bits,
	* triggered by input voltage alarms. In many designs, those alarms are
	* associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin
	* to the OV pin. ADIN2 is, however, not available on all chip variants.
	* To ensure that the alarm condition is reported to the user, report it
	* with both voltage sensors.
	*/
	LTC4261_BOOL(in1_min_alarm, FAULT_UV);
	LTC4261_BOOL(in1_max_alarm, FAULT_OV);
	LTC4261_BOOL(in2_min_alarm, FAULT_UV);
	LTC4261_BOOL(in2_max_alarm, FAULT_OV);

	/* Currents (via sense resistor) */
	LTC4261_VALUE(curr1_input, LTC4261_SENSE_H);

	/* Overcurrent alarm */
	LTC4261_BOOL(curr1_max_alarm, FAULT_OC);

	static struct attribute *ltc4261_attributes[] = {
	&sensor_dev_attr_in1_input.dev_attr.attr,
	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
	&sensor_dev_attr_in2_input.dev_attr.attr,
	&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in2_max_alarm.dev_attr.attr,

	&sensor_dev_attr_curr1_input.dev_attr.attr,
	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,

	NULL,
	};

	static const struct attribute_group ltc4261_group = {
	.attrs = ltc4261_attributes,
	};

	static int ltc4261_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct i2c_adapter *adapter = client->adapter;
	struct ltc4261_data *data;
	int ret;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
	return -ENODEV;

	if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) {
	dev_err(&client->dev, "Failed to read status register\n");
	return -ENODEV;
	}

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data) {
	ret = -ENOMEM;
	goto out_kzalloc;
	}

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

	/* Clear faults */
	i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00);

	/* Register sysfs hooks */
	ret = sysfs_create_group(&client->dev.kobj, &ltc4261_group);
	if (ret)
	goto out_sysfs_create_group;

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

	return 0;

	out_hwmon_device_register:
	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);
	out_sysfs_create_group:
	kfree(data);
	out_kzalloc:
	return ret;
	}

	static int ltc4261_remove(struct i2c_client *client)
	{
	struct ltc4261_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &ltc4261_group);

	kfree(data);

	return 0;
	}

	static const struct i2c_device_id ltc4261_id[] = {
	{"ltc4261", 0},
	{}
	};

	MODULE_DEVICE_TABLE(i2c, ltc4261_id);

	/* This is the driver that will be inserted */
	static struct i2c_driver ltc4261_driver = {
	.driver = {
	.name = "ltc4261",
	},
	.probe = ltc4261_probe,
	.remove = ltc4261_remove,
	.id_table = ltc4261_id,
	};

	module_i2c_driver(ltc4261_driver);

	MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
	MODULE_DESCRIPTION("LTC4261 driver");
	MODULE_LICENSE("GPL");