drivers/hwmon/ltc4222.c - arm/linux - Git at Google

 /*
  * Driver for Linear Technology LTC4222 Dual Hot Swap controller
  *
  * Copyright (c) 2014 Guenter Roeck
  *
  * 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.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/bitops.h>
 #include <linux/i2c.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/jiffies.h>
 #include <linux/regmap.h>

 /* chip registers */

 #define LTC4222_CONTROL1	0xd0
 #define LTC4222_ALERT1		0xd1
 #define LTC4222_STATUS1		0xd2
 #define LTC4222_FAULT1		0xd3
 #define LTC4222_CONTROL2	0xd4
 #define LTC4222_ALERT2		0xd5
 #define LTC4222_STATUS2		0xd6
 #define LTC4222_FAULT2		0xd7
 #define LTC4222_SOURCE1		0xd8
 #define LTC4222_SOURCE2		0xda
 #define LTC4222_ADIN1		0xdc
 #define LTC4222_ADIN2		0xde
 #define LTC4222_SENSE1		0xe0
 #define LTC4222_SENSE2		0xe2
 #define LTC4222_ADC_CONTROL	0xe4

 /*
  * Fault register bits
  */
 #define FAULT_OV	BIT(0)
 #define FAULT_UV	BIT(1)
 #define FAULT_OC	BIT(2)
 #define FAULT_POWER_BAD	BIT(3)
 #define FAULT_FET_BAD	BIT(5)

 /* Return the voltage from the given register in mV or mA */
 static int ltc4222_get_value(struct device *dev, u8 reg)
 {
 	struct regmap *regmap = dev_get_drvdata(dev);
 	unsigned int val;
 	u8 buf[2];
 	int ret;

 	ret = regmap_bulk_read(regmap, reg, buf, 2);
 	if (ret < 0)
 		return ret;

 	val = ((buf[0] << 8) + buf[1]) >> 6;

 	switch (reg) {
 	case LTC4222_ADIN1:
 	case LTC4222_ADIN2:
 		/* 1.25 mV resolution. Convert to mV. */
 		val = DIV_ROUND_CLOSEST(val * 5, 4);
 		break;
 	case LTC4222_SOURCE1:
 	case LTC4222_SOURCE2:
 		/* 31.25 mV resolution. Convert to mV. */
 		val = DIV_ROUND_CLOSEST(val * 125, 4);
 		break;
 	case LTC4222_SENSE1:
 	case LTC4222_SENSE2:
 		/*
 		 * 62.5 uV 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 = DIV_ROUND_CLOSEST(val * 125, 2);
 		break;
 	default:
 		return -EINVAL;
 	}
 	return val;
 }

 static ssize_t ltc4222_show_value(struct device *dev,
 				  struct device_attribute *da, char *buf)
 {
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 	int value;

 	value = ltc4222_get_value(dev, attr->index);
 	if (value < 0)
 		return value;
 	return snprintf(buf, PAGE_SIZE, "%d\n", value);
 }

 static ssize_t ltc4222_show_bool(struct device *dev,
 				 struct device_attribute *da, char *buf)
 {
 	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
 	struct regmap *regmap = dev_get_drvdata(dev);
 	unsigned int fault;
 	int ret;

 	ret = regmap_read(regmap, attr->nr, &fault);
 	if (ret < 0)
 		return ret;
 	fault &= attr->index;
 	if (fault)		/* Clear reported faults in chip register */
 		regmap_update_bits(regmap, attr->nr, attr->index, 0);

 	return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
 }

 /* Voltages */
 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4222_show_value, NULL,
 			  LTC4222_SOURCE1);
 static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4222_show_value, NULL,
 			  LTC4222_ADIN1);
 static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4222_show_value, NULL,
 			  LTC4222_SOURCE2);
 static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4222_show_value, NULL,
 			  LTC4222_ADIN2);

 /*
  * Voltage alarms
  * UV/OV faults are associated with the input voltage, and power bad and fet
  * faults are associated with the output voltage.
  */
 static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 			    LTC4222_FAULT1, FAULT_UV);
 static SENSOR_DEVICE_ATTR_2(in1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 			    LTC4222_FAULT1, FAULT_OV);
 static SENSOR_DEVICE_ATTR_2(in2_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 			    LTC4222_FAULT1, FAULT_POWER_BAD | FAULT_FET_BAD);

 static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 			    LTC4222_FAULT2, FAULT_UV);
 static SENSOR_DEVICE_ATTR_2(in3_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 			    LTC4222_FAULT2, FAULT_OV);
 static SENSOR_DEVICE_ATTR_2(in4_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 			    LTC4222_FAULT2, FAULT_POWER_BAD | FAULT_FET_BAD);

 /* Current (via sense resistor) */
 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4222_show_value, NULL,
 			  LTC4222_SENSE1);
 static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4222_show_value, NULL,
 			  LTC4222_SENSE2);

 /* Overcurrent alarm */
 static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 			    LTC4222_FAULT1, FAULT_OC);
 static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 			    LTC4222_FAULT2, FAULT_OC);

 static struct attribute *ltc4222_attrs[] = {
 	&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_alarm.dev_attr.attr,
 	&sensor_dev_attr_in3_input.dev_attr.attr,
 	&sensor_dev_attr_in3_min_alarm.dev_attr.attr,
 	&sensor_dev_attr_in3_max_alarm.dev_attr.attr,
 	&sensor_dev_attr_in4_input.dev_attr.attr,
 	&sensor_dev_attr_in4_alarm.dev_attr.attr,

 	&sensor_dev_attr_curr1_input.dev_attr.attr,
 	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
 	&sensor_dev_attr_curr2_input.dev_attr.attr,
 	&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,

 	NULL,
 };
 ATTRIBUTE_GROUPS(ltc4222);

 static const struct regmap_config ltc4222_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.max_register = LTC4222_ADC_CONTROL,
 };

 static int ltc4222_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
 	struct device *hwmon_dev;
 	struct regmap *regmap;

 	regmap = devm_regmap_init_i2c(client, &ltc4222_regmap_config);
 	if (IS_ERR(regmap)) {
 		dev_err(dev, "failed to allocate register map\n");
 		return PTR_ERR(regmap);
 	}

 	/* Clear faults */
 	regmap_write(regmap, LTC4222_FAULT1, 0x00);
 	regmap_write(regmap, LTC4222_FAULT2, 0x00);

 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 							   regmap,
 							   ltc4222_groups);
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }

 static const struct i2c_device_id ltc4222_id[] = {
 	{"ltc4222", 0},
 	{ }
 };

 MODULE_DEVICE_TABLE(i2c, ltc4222_id);

 static struct i2c_driver ltc4222_driver = {
 	.driver = {
 		   .name = "ltc4222",
 		   },
 	.probe = ltc4222_probe,
 	.id_table = ltc4222_id,
 };

 module_i2c_driver(ltc4222_driver);

 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 MODULE_DESCRIPTION("LTC4222 driver");
 MODULE_LICENSE("GPL");
	/*
	* Driver for Linear Technology LTC4222 Dual Hot Swap controller
	*
	* Copyright (c) 2014 Guenter Roeck
	*
	* 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.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/err.h>
	#include <linux/slab.h>
	#include <linux/bitops.h>
	#include <linux/i2c.h>
	#include <linux/hwmon.h>
	#include <linux/hwmon-sysfs.h>
	#include <linux/jiffies.h>
	#include <linux/regmap.h>

	/* chip registers */

	#define LTC4222_CONTROL1 0xd0
	#define LTC4222_ALERT1 0xd1
	#define LTC4222_STATUS1 0xd2
	#define LTC4222_FAULT1 0xd3
	#define LTC4222_CONTROL2 0xd4
	#define LTC4222_ALERT2 0xd5
	#define LTC4222_STATUS2 0xd6
	#define LTC4222_FAULT2 0xd7
	#define LTC4222_SOURCE1 0xd8
	#define LTC4222_SOURCE2 0xda
	#define LTC4222_ADIN1 0xdc
	#define LTC4222_ADIN2 0xde
	#define LTC4222_SENSE1 0xe0
	#define LTC4222_SENSE2 0xe2
	#define LTC4222_ADC_CONTROL 0xe4

	/*
	* Fault register bits
	*/
	#define FAULT_OV BIT(0)
	#define FAULT_UV BIT(1)
	#define FAULT_OC BIT(2)
	#define FAULT_POWER_BAD BIT(3)
	#define FAULT_FET_BAD BIT(5)

	/* Return the voltage from the given register in mV or mA */
	static int ltc4222_get_value(struct device *dev, u8 reg)
	{
	struct regmap *regmap = dev_get_drvdata(dev);
	unsigned int val;
	u8 buf[2];
	int ret;

	ret = regmap_bulk_read(regmap, reg, buf, 2);
	if (ret < 0)
	return ret;

	val = ((buf[0] << 8) + buf[1]) >> 6;

	switch (reg) {
	case LTC4222_ADIN1:
	case LTC4222_ADIN2:
	/* 1.25 mV resolution. Convert to mV. */
	val = DIV_ROUND_CLOSEST(val * 5, 4);
	break;
	case LTC4222_SOURCE1:
	case LTC4222_SOURCE2:
	/* 31.25 mV resolution. Convert to mV. */
	val = DIV_ROUND_CLOSEST(val * 125, 4);
	break;
	case LTC4222_SENSE1:
	case LTC4222_SENSE2:
	/*
	* 62.5 uV 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 = DIV_ROUND_CLOSEST(val * 125, 2);
	break;
	default:
	return -EINVAL;
	}
	return val;
	}

	static ssize_t ltc4222_show_value(struct device *dev,
	struct device_attribute da, char buf)
	{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	int value;

	value = ltc4222_get_value(dev, attr->index);
	if (value < 0)
	return value;
	return snprintf(buf, PAGE_SIZE, "%d\n", value);
	}

	static ssize_t ltc4222_show_bool(struct device *dev,
	struct device_attribute da, char buf)
	{
	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
	struct regmap *regmap = dev_get_drvdata(dev);
	unsigned int fault;
	int ret;

	ret = regmap_read(regmap, attr->nr, &fault);
	if (ret < 0)
	return ret;
	fault &= attr->index;
	if (fault) /* Clear reported faults in chip register */
	regmap_update_bits(regmap, attr->nr, attr->index, 0);

	return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
	}

	/* Voltages */
	static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4222_show_value, NULL,
	LTC4222_SOURCE1);
	static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4222_show_value, NULL,
	LTC4222_ADIN1);
	static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4222_show_value, NULL,
	LTC4222_SOURCE2);
	static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4222_show_value, NULL,
	LTC4222_ADIN2);

	/*
	* Voltage alarms
	* UV/OV faults are associated with the input voltage, and power bad and fet
	* faults are associated with the output voltage.
	*/
	static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
	LTC4222_FAULT1, FAULT_UV);
	static SENSOR_DEVICE_ATTR_2(in1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
	LTC4222_FAULT1, FAULT_OV);
	static SENSOR_DEVICE_ATTR_2(in2_alarm, S_IRUGO, ltc4222_show_bool, NULL,
	LTC4222_FAULT1, FAULT_POWER_BAD \| FAULT_FET_BAD);

	static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
	LTC4222_FAULT2, FAULT_UV);
	static SENSOR_DEVICE_ATTR_2(in3_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
	LTC4222_FAULT2, FAULT_OV);
	static SENSOR_DEVICE_ATTR_2(in4_alarm, S_IRUGO, ltc4222_show_bool, NULL,
	LTC4222_FAULT2, FAULT_POWER_BAD \| FAULT_FET_BAD);

	/* Current (via sense resistor) */
	static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4222_show_value, NULL,
	LTC4222_SENSE1);
	static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4222_show_value, NULL,
	LTC4222_SENSE2);

	/* Overcurrent alarm */
	static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
	LTC4222_FAULT1, FAULT_OC);
	static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
	LTC4222_FAULT2, FAULT_OC);

	static struct attribute *ltc4222_attrs[] = {
	&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_alarm.dev_attr.attr,
	&sensor_dev_attr_in3_input.dev_attr.attr,
	&sensor_dev_attr_in3_min_alarm.dev_attr.attr,
	&sensor_dev_attr_in3_max_alarm.dev_attr.attr,
	&sensor_dev_attr_in4_input.dev_attr.attr,
	&sensor_dev_attr_in4_alarm.dev_attr.attr,

	&sensor_dev_attr_curr1_input.dev_attr.attr,
	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
	&sensor_dev_attr_curr2_input.dev_attr.attr,
	&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,

	NULL,
	};
	ATTRIBUTE_GROUPS(ltc4222);

	static const struct regmap_config ltc4222_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = LTC4222_ADC_CONTROL,
	};

	static int ltc4222_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct device *dev = &client->dev;
	struct device *hwmon_dev;
	struct regmap *regmap;

	regmap = devm_regmap_init_i2c(client, &ltc4222_regmap_config);
	if (IS_ERR(regmap)) {
	dev_err(dev, "failed to allocate register map\n");
	return PTR_ERR(regmap);
	}

	/* Clear faults */
	regmap_write(regmap, LTC4222_FAULT1, 0x00);
	regmap_write(regmap, LTC4222_FAULT2, 0x00);

	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
	regmap,
	ltc4222_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
	}

	static const struct i2c_device_id ltc4222_id[] = {
	{"ltc4222", 0},
	{ }
	};

	MODULE_DEVICE_TABLE(i2c, ltc4222_id);

	static struct i2c_driver ltc4222_driver = {
	.driver = {
	.name = "ltc4222",
	},
	.probe = ltc4222_probe,
	.id_table = ltc4222_id,
	};

	module_i2c_driver(ltc4222_driver);

	MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
	MODULE_DESCRIPTION("LTC4222 driver");
	MODULE_LICENSE("GPL");