drivers/hwmon/ina2xx.c - kernel/msm-4.9 - Gitiles

 /*
  * Driver for Texas Instruments INA219, INA226 power monitor chips
  *
  * INA219:
  * Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
  * Datasheet: http://www.ti.com/product/ina219
  *
  * INA220:
  * Bi-Directional Current/Power Monitor with I2C Interface
  * Datasheet: http://www.ti.com/product/ina220
  *
  * INA226:
  * Bi-Directional Current/Power Monitor with I2C Interface
  * Datasheet: http://www.ti.com/product/ina226
  *
  * INA230:
  * Bi-directional Current/Power Monitor with I2C Interface
  * Datasheet: http://www.ti.com/product/ina230
  *
  * Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
  * Thanks to Jan Volkering
  *
  * 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; version 2 of the License.
  */

 #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>
 #include <linux/jiffies.h>
 #include <linux/of.h>
 #include <linux/delay.h>
 #include <linux/util_macros.h>

 #include <linux/platform_data/ina2xx.h>

 /* common register definitions */
 #define INA2XX_CONFIG			0x00
 #define INA2XX_SHUNT_VOLTAGE		0x01 /* readonly */
 #define INA2XX_BUS_VOLTAGE		0x02 /* readonly */
 #define INA2XX_POWER			0x03 /* readonly */
 #define INA2XX_CURRENT			0x04 /* readonly */
 #define INA2XX_CALIBRATION		0x05

 /* INA226 register definitions */
 #define INA226_MASK_ENABLE		0x06
 #define INA226_ALERT_LIMIT		0x07
 #define INA226_DIE_ID			0xFF

 /* register count */
 #define INA219_REGISTERS		6
 #define INA226_REGISTERS		8

 #define INA2XX_MAX_REGISTERS		8

 /* settings - depend on use case */
 #define INA219_CONFIG_DEFAULT		0x399F	/* PGA=8 */
 #define INA226_CONFIG_DEFAULT		0x4527	/* averages=16 */

 /* worst case is 68.10 ms (~14.6Hz, ina219) */
 #define INA2XX_CONVERSION_RATE		15
 #define INA2XX_MAX_DELAY		69 /* worst case delay in ms */

 #define INA2XX_RSHUNT_DEFAULT		10000

 /* bit mask for reading the averaging setting in the configuration register */
 #define INA226_AVG_RD_MASK		0x0E00

 #define INA226_READ_AVG(reg)		(((reg) & INA226_AVG_RD_MASK) >> 9)
 #define INA226_SHIFT_AVG(val)		((val) << 9)

 /* common attrs, ina226 attrs and NULL */
 #define INA2XX_MAX_ATTRIBUTE_GROUPS	3

 /*
  * Both bus voltage and shunt voltage conversion times for ina226 are set
  * to 0b0100 on POR, which translates to 2200 microseconds in total.
  */
 #define INA226_TOTAL_CONV_TIME_DEFAULT	2200

 enum ina2xx_ids { ina219, ina226 };

 struct ina2xx_config {
 	u16 config_default;
 	int calibration_factor;
 	int registers;
 	int shunt_div;
 	int bus_voltage_shift;
 	int bus_voltage_lsb;	/* uV */
 	int power_lsb;		/* uW */
 };

 struct ina2xx_data {
 	struct i2c_client *client;
 	const struct ina2xx_config *config;

 	long rshunt;
 	u16 curr_config;

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

 	int kind;
 	const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
 	u16 regs[INA2XX_MAX_REGISTERS];
 };

 static const struct ina2xx_config ina2xx_config[] = {
 	[ina219] = {
 		.config_default = INA219_CONFIG_DEFAULT,
 		.calibration_factor = 40960000,
 		.registers = INA219_REGISTERS,
 		.shunt_div = 100,
 		.bus_voltage_shift = 3,
 		.bus_voltage_lsb = 4000,
 		.power_lsb = 20000,
 	},
 	[ina226] = {
 		.config_default = INA226_CONFIG_DEFAULT,
 		.calibration_factor = 5120000,
 		.registers = INA226_REGISTERS,
 		.shunt_div = 400,
 		.bus_voltage_shift = 0,
 		.bus_voltage_lsb = 1250,
 		.power_lsb = 25000,
 	},
 };

 /*
  * Available averaging rates for ina226. The indices correspond with
  * the bit values expected by the chip (according to the ina226 datasheet,
  * table 3 AVG bit settings, found at
  * http://www.ti.com/lit/ds/symlink/ina226.pdf.
  */
 static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };

 static int ina226_reg_to_interval(u16 config)
 {
 	int avg = ina226_avg_tab[INA226_READ_AVG(config)];

 	/*
 	 * Multiply the total conversion time by the number of averages.
 	 * Return the result in milliseconds.
 	 */
 	return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
 }

 static u16 ina226_interval_to_reg(int interval, u16 config)
 {
 	int avg, avg_bits;

 	avg = DIV_ROUND_CLOSEST(interval * 1000,
 				INA226_TOTAL_CONV_TIME_DEFAULT);
 	avg_bits = find_closest(avg, ina226_avg_tab,
 				ARRAY_SIZE(ina226_avg_tab));

 	return (config & ~INA226_AVG_RD_MASK) | INA226_SHIFT_AVG(avg_bits);
 }

 static void ina226_set_update_interval(struct ina2xx_data *data)
 {
 	int ms;

 	ms = ina226_reg_to_interval(data->curr_config);
 	data->update_interval = msecs_to_jiffies(ms);
 }

 static int ina2xx_calibrate(struct ina2xx_data *data)
 {
 	u16 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
 				    data->rshunt);

 	return i2c_smbus_write_word_swapped(data->client,
 					    INA2XX_CALIBRATION, val);
 }

 /*
  * Initialize the configuration and calibration registers.
  */
 static int ina2xx_init(struct ina2xx_data *data)
 {
 	struct i2c_client *client = data->client;
 	int ret;

 	/* device configuration */
 	ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 					   data->curr_config);
 	if (ret < 0)
 		return ret;

 	/*
 	 * Set current LSB to 1mA, shunt is in uOhms
 	 * (equation 13 in datasheet).
 	 */
 	return ina2xx_calibrate(data);
 }

 static int ina2xx_do_update(struct device *dev)
 {
 	struct ina2xx_data *data = dev_get_drvdata(dev);
 	struct i2c_client *client = data->client;
 	int i, rv, retry;

 	dev_dbg(&client->dev, "Starting ina2xx update\n");

 	for (retry = 5; retry; retry--) {
 		/* Read all registers */
 		for (i = 0; i < data->config->registers; i++) {
 			rv = i2c_smbus_read_word_swapped(client, i);
 			if (rv < 0)
 				return rv;
 			data->regs[i] = rv;
 		}

 		/*
 		 * If the current value in the calibration register is 0, the
 		 * power and current registers will also remain at 0. In case
 		 * the chip has been reset let's check the calibration
 		 * register and reinitialize if needed.
 		 */
 		if (data->regs[INA2XX_CALIBRATION] == 0) {
 			dev_warn(dev, "chip not calibrated, reinitializing\n");

 			rv = ina2xx_init(data);
 			if (rv < 0)
 				return rv;

 			/*
 			 * Let's make sure the power and current registers
 			 * have been updated before trying again.
 			 */
 			msleep(INA2XX_MAX_DELAY);
 			continue;
 		}

 		data->last_updated = jiffies;
 		data->valid = 1;

 		return 0;
 	}

 	/*
 	 * If we're here then although all write operations succeeded, the
 	 * chip still returns 0 in the calibration register. Nothing more we
 	 * can do here.
 	 */
 	dev_err(dev, "unable to reinitialize the chip\n");
 	return -ENODEV;
 }

 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
 {
 	struct ina2xx_data *data = dev_get_drvdata(dev);
 	struct ina2xx_data *ret = data;
 	unsigned long after;
 	int rv;

 	mutex_lock(&data->update_lock);

 	after = data->last_updated + data->update_interval;
 	if (time_after(jiffies, after) || !data->valid) {
 		rv = ina2xx_do_update(dev);
 		if (rv < 0)
 			ret = ERR_PTR(rv);
 	}

 	mutex_unlock(&data->update_lock);
 	return ret;
 }

 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
 {
 	int val;

 	switch (reg) {
 	case INA2XX_SHUNT_VOLTAGE:
 		/* signed register */
 		val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
 					data->config->shunt_div);
 		break;
 	case INA2XX_BUS_VOLTAGE:
 		val = (data->regs[reg] >> data->config->bus_voltage_shift)
 		  * data->config->bus_voltage_lsb;
 		val = DIV_ROUND_CLOSEST(val, 1000);
 		break;
 	case INA2XX_POWER:
 		val = data->regs[reg] * data->config->power_lsb;
 		break;
 	case INA2XX_CURRENT:
 		/* signed register, LSB=1mA (selected), in mA */
 		val = (s16)data->regs[reg];
 		break;
 	case INA2XX_CALIBRATION:
 		val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
 					data->regs[reg]);
 		break;
 	default:
 		/* programmer goofed */
 		WARN_ON_ONCE(1);
 		val = 0;
 		break;
 	}

 	return val;
 }

 static ssize_t ina2xx_show_value(struct device *dev,
 				 struct device_attribute *da, char *buf)
 {
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 	struct ina2xx_data *data = ina2xx_update_device(dev);

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

 	return snprintf(buf, PAGE_SIZE, "%d\n",
 			ina2xx_get_value(data, attr->index));
 }

 static ssize_t ina2xx_set_shunt(struct device *dev,
 				struct device_attribute *da,
 				const char *buf, size_t count)
 {
 	struct ina2xx_data *data = ina2xx_update_device(dev);
 	unsigned long val;
 	int status;

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

 	status = kstrtoul(buf, 10, &val);
 	if (status < 0)
 		return status;

 	if (val == 0 ||
 	    /* Values greater than the calibration factor make no sense. */
 	    val > data->config->calibration_factor)
 		return -EINVAL;

 	mutex_lock(&data->update_lock);
 	data->rshunt = val;
 	status = ina2xx_calibrate(data);
 	mutex_unlock(&data->update_lock);
 	if (status < 0)
 		return status;

 	return count;
 }

 static ssize_t ina226_set_interval(struct device *dev,
 				   struct device_attribute *da,
 				   const char *buf, size_t count)
 {
 	struct ina2xx_data *data = dev_get_drvdata(dev);
 	unsigned long val;
 	int status;

 	status = kstrtoul(buf, 10, &val);
 	if (status < 0)
 		return status;

 	if (val > INT_MAX || val == 0)
 		return -EINVAL;

 	mutex_lock(&data->update_lock);
 	data->curr_config = ina226_interval_to_reg(val,
 						   data->regs[INA2XX_CONFIG]);
 	status = i2c_smbus_write_word_swapped(data->client,
 					      INA2XX_CONFIG,
 					      data->curr_config);

 	ina226_set_update_interval(data);
 	/* Make sure the next access re-reads all registers. */
 	data->valid = 0;
 	mutex_unlock(&data->update_lock);
 	if (status < 0)
 		return status;

 	return count;
 }

 static ssize_t ina226_show_interval(struct device *dev,
 				    struct device_attribute *da, char *buf)
 {
 	struct ina2xx_data *data = ina2xx_update_device(dev);

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

 	/*
 	 * We don't use data->update_interval here as we want to display
 	 * the actual interval used by the chip and jiffies_to_msecs()
 	 * doesn't seem to be accurate enough.
 	 */
 	return snprintf(buf, PAGE_SIZE, "%d\n",
 			ina226_reg_to_interval(data->regs[INA2XX_CONFIG]));
 }

 /* shunt voltage */
 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 			  INA2XX_SHUNT_VOLTAGE);

 /* bus voltage */
 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 			  INA2XX_BUS_VOLTAGE);

 /* calculated current */
 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 			  INA2XX_CURRENT);

 /* calculated power */
 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 			  INA2XX_POWER);

 /* shunt resistance */
 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
 			  ina2xx_show_value, ina2xx_set_shunt,
 			  INA2XX_CALIBRATION);

 /* update interval (ina226 only) */
 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
 			  ina226_show_interval, ina226_set_interval, 0);

 /* pointers to created device attributes */
 static struct attribute *ina2xx_attrs[] = {
 	&sensor_dev_attr_in0_input.dev_attr.attr,
 	&sensor_dev_attr_in1_input.dev_attr.attr,
 	&sensor_dev_attr_curr1_input.dev_attr.attr,
 	&sensor_dev_attr_power1_input.dev_attr.attr,
 	&sensor_dev_attr_shunt_resistor.dev_attr.attr,
 	NULL,
 };

 static const struct attribute_group ina2xx_group = {
 	.attrs = ina2xx_attrs,
 };

 static struct attribute *ina226_attrs[] = {
 	&sensor_dev_attr_update_interval.dev_attr.attr,
 	NULL,
 };

 static const struct attribute_group ina226_group = {
 	.attrs = ina226_attrs,
 };

 static int ina2xx_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct i2c_adapter *adapter = client->adapter;
 	struct ina2xx_platform_data *pdata;
 	struct device *dev = &client->dev;
 	struct ina2xx_data *data;
 	struct device *hwmon_dev;
 	u32 val;
 	int ret, group = 0;

 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 		return -ENODEV;

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

 	if (dev_get_platdata(dev)) {
 		pdata = dev_get_platdata(dev);
 		data->rshunt = pdata->shunt_uohms;
 	} else if (!of_property_read_u32(dev->of_node,
 					 "shunt-resistor", &val)) {
 		data->rshunt = val;
 	} else {
 		data->rshunt = INA2XX_RSHUNT_DEFAULT;
 	}

 	/* set the device type */
 	data->kind = id->driver_data;
 	data->config = &ina2xx_config[data->kind];
 	data->curr_config = data->config->config_default;
 	data->client = client;

 	/*
 	 * Ina226 has a variable update_interval. For ina219 we
 	 * use a constant value.
 	 */
 	if (data->kind == ina226)
 		ina226_set_update_interval(data);
 	else
 		data->update_interval = HZ / INA2XX_CONVERSION_RATE;

 	if (data->rshunt <= 0 ||
 	    data->rshunt > data->config->calibration_factor)
 		return -ENODEV;

 	ret = ina2xx_init(data);
 	if (ret < 0) {
 		dev_err(dev, "error configuring the device: %d\n", ret);
 		return -ENODEV;
 	}

 	mutex_init(&data->update_lock);

 	data->groups[group++] = &ina2xx_group;
 	if (data->kind == ina226)
 		data->groups[group++] = &ina226_group;

 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 							   data, data->groups);
 	if (IS_ERR(hwmon_dev))
 		return PTR_ERR(hwmon_dev);

 	dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 		 id->name, data->rshunt);

 	return 0;
 }

 static const struct i2c_device_id ina2xx_id[] = {
 	{ "ina219", ina219 },
 	{ "ina220", ina219 },
 	{ "ina226", ina226 },
 	{ "ina230", ina226 },
 	{ "ina231", ina226 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ina2xx_id);

 static struct i2c_driver ina2xx_driver = {
 	.driver = {
 		.name	= "ina2xx",
 	},
 	.probe		= ina2xx_probe,
 	.id_table	= ina2xx_id,
 };

 module_i2c_driver(ina2xx_driver);

 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 MODULE_DESCRIPTION("ina2xx driver");
 MODULE_LICENSE("GPL");
	/*
	* Driver for Texas Instruments INA219, INA226 power monitor chips
	*
	* INA219:
	* Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
	* Datasheet: http://www.ti.com/product/ina219
	*
	* INA220:
	* Bi-Directional Current/Power Monitor with I2C Interface
	* Datasheet: http://www.ti.com/product/ina220
	*
	* INA226:
	* Bi-Directional Current/Power Monitor with I2C Interface
	* Datasheet: http://www.ti.com/product/ina226
	*
	* INA230:
	* Bi-directional Current/Power Monitor with I2C Interface
	* Datasheet: http://www.ti.com/product/ina230
	*
	* Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
	* Thanks to Jan Volkering
	*
	* 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; version 2 of the License.
	*/

	#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>
	#include <linux/jiffies.h>
	#include <linux/of.h>
	#include <linux/delay.h>
	#include <linux/util_macros.h>

	#include <linux/platform_data/ina2xx.h>

	/* common register definitions */
	#define INA2XX_CONFIG 0x00
	#define INA2XX_SHUNT_VOLTAGE 0x01 /* readonly */
	#define INA2XX_BUS_VOLTAGE 0x02 /* readonly */
	#define INA2XX_POWER 0x03 /* readonly */
	#define INA2XX_CURRENT 0x04 /* readonly */
	#define INA2XX_CALIBRATION 0x05

	/* INA226 register definitions */
	#define INA226_MASK_ENABLE 0x06
	#define INA226_ALERT_LIMIT 0x07
	#define INA226_DIE_ID 0xFF

	/* register count */
	#define INA219_REGISTERS 6
	#define INA226_REGISTERS 8

	#define INA2XX_MAX_REGISTERS 8

	/* settings - depend on use case */
	#define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */
	#define INA226_CONFIG_DEFAULT 0x4527 /* averages=16 */

	/* worst case is 68.10 ms (~14.6Hz, ina219) */
	#define INA2XX_CONVERSION_RATE 15
	#define INA2XX_MAX_DELAY 69 /* worst case delay in ms */

	#define INA2XX_RSHUNT_DEFAULT 10000

	/* bit mask for reading the averaging setting in the configuration register */
	#define INA226_AVG_RD_MASK 0x0E00

	#define INA226_READ_AVG(reg) (((reg) & INA226_AVG_RD_MASK) >> 9)
	#define INA226_SHIFT_AVG(val) ((val) << 9)

	/* common attrs, ina226 attrs and NULL */
	#define INA2XX_MAX_ATTRIBUTE_GROUPS 3

	/*
	* Both bus voltage and shunt voltage conversion times for ina226 are set
	* to 0b0100 on POR, which translates to 2200 microseconds in total.
	*/
	#define INA226_TOTAL_CONV_TIME_DEFAULT 2200

	enum ina2xx_ids { ina219, ina226 };

	struct ina2xx_config {
	u16 config_default;
	int calibration_factor;
	int registers;
	int shunt_div;
	int bus_voltage_shift;
	int bus_voltage_lsb; /* uV */
	int power_lsb; /* uW */
	};

	struct ina2xx_data {
	struct i2c_client *client;
	const struct ina2xx_config *config;

	long rshunt;
	u16 curr_config;

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

	int kind;
	const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
	u16 regs[INA2XX_MAX_REGISTERS];
	};

	static const struct ina2xx_config ina2xx_config[] = {
	[ina219] = {
	.config_default = INA219_CONFIG_DEFAULT,
	.calibration_factor = 40960000,
	.registers = INA219_REGISTERS,
	.shunt_div = 100,
	.bus_voltage_shift = 3,
	.bus_voltage_lsb = 4000,
	.power_lsb = 20000,
	},
	[ina226] = {
	.config_default = INA226_CONFIG_DEFAULT,
	.calibration_factor = 5120000,
	.registers = INA226_REGISTERS,
	.shunt_div = 400,
	.bus_voltage_shift = 0,
	.bus_voltage_lsb = 1250,
	.power_lsb = 25000,
	},
	};

	/*
	* Available averaging rates for ina226. The indices correspond with
	* the bit values expected by the chip (according to the ina226 datasheet,
	* table 3 AVG bit settings, found at
	* http://www.ti.com/lit/ds/symlink/ina226.pdf.
	*/
	static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };

	static int ina226_reg_to_interval(u16 config)
	{
	int avg = ina226_avg_tab[INA226_READ_AVG(config)];

	/*
	* Multiply the total conversion time by the number of averages.
	* Return the result in milliseconds.
	*/
	return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
	}

	static u16 ina226_interval_to_reg(int interval, u16 config)
	{
	int avg, avg_bits;

	avg = DIV_ROUND_CLOSEST(interval * 1000,
	INA226_TOTAL_CONV_TIME_DEFAULT);
	avg_bits = find_closest(avg, ina226_avg_tab,
	ARRAY_SIZE(ina226_avg_tab));

	return (config & ~INA226_AVG_RD_MASK) \| INA226_SHIFT_AVG(avg_bits);
	}

	static void ina226_set_update_interval(struct ina2xx_data *data)
	{
	int ms;

	ms = ina226_reg_to_interval(data->curr_config);
	data->update_interval = msecs_to_jiffies(ms);
	}

	static int ina2xx_calibrate(struct ina2xx_data *data)
	{
	u16 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
	data->rshunt);

	return i2c_smbus_write_word_swapped(data->client,
	INA2XX_CALIBRATION, val);
	}

	/*
	* Initialize the configuration and calibration registers.
	*/
	static int ina2xx_init(struct ina2xx_data *data)
	{
	struct i2c_client *client = data->client;
	int ret;

	/* device configuration */
	ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
	data->curr_config);
	if (ret < 0)
	return ret;

	/*
	* Set current LSB to 1mA, shunt is in uOhms
	* (equation 13 in datasheet).
	*/
	return ina2xx_calibrate(data);
	}

	static int ina2xx_do_update(struct device *dev)
	{
	struct ina2xx_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	int i, rv, retry;

	dev_dbg(&client->dev, "Starting ina2xx update\n");

	for (retry = 5; retry; retry--) {
	/* Read all registers */
	for (i = 0; i < data->config->registers; i++) {
	rv = i2c_smbus_read_word_swapped(client, i);
	if (rv < 0)
	return rv;
	data->regs[i] = rv;
	}

	/*
	* If the current value in the calibration register is 0, the
	* power and current registers will also remain at 0. In case
	* the chip has been reset let's check the calibration
	* register and reinitialize if needed.
	*/
	if (data->regs[INA2XX_CALIBRATION] == 0) {
	dev_warn(dev, "chip not calibrated, reinitializing\n");

	rv = ina2xx_init(data);
	if (rv < 0)
	return rv;

	/*
	* Let's make sure the power and current registers
	* have been updated before trying again.
	*/
	msleep(INA2XX_MAX_DELAY);
	continue;
	}

	data->last_updated = jiffies;
	data->valid = 1;

	return 0;
	}

	/*
	* If we're here then although all write operations succeeded, the
	* chip still returns 0 in the calibration register. Nothing more we
	* can do here.
	*/
	dev_err(dev, "unable to reinitialize the chip\n");
	return -ENODEV;
	}

	static struct ina2xx_data ina2xx_update_device(struct device dev)
	{
	struct ina2xx_data *data = dev_get_drvdata(dev);
	struct ina2xx_data *ret = data;
	unsigned long after;
	int rv;

	mutex_lock(&data->update_lock);

	after = data->last_updated + data->update_interval;
	if (time_after(jiffies, after) \|\| !data->valid) {
	rv = ina2xx_do_update(dev);
	if (rv < 0)
	ret = ERR_PTR(rv);
	}

	mutex_unlock(&data->update_lock);
	return ret;
	}

	static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
	{
	int val;

	switch (reg) {
	case INA2XX_SHUNT_VOLTAGE:
	/* signed register */
	val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
	data->config->shunt_div);
	break;
	case INA2XX_BUS_VOLTAGE:
	val = (data->regs[reg] >> data->config->bus_voltage_shift)
	* data->config->bus_voltage_lsb;
	val = DIV_ROUND_CLOSEST(val, 1000);
	break;
	case INA2XX_POWER:
	val = data->regs[reg] * data->config->power_lsb;
	break;
	case INA2XX_CURRENT:
	/* signed register, LSB=1mA (selected), in mA */
	val = (s16)data->regs[reg];
	break;
	case INA2XX_CALIBRATION:
	val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
	data->regs[reg]);
	break;
	default:
	/* programmer goofed */
	WARN_ON_ONCE(1);
	val = 0;
	break;
	}

	return val;
	}

	static ssize_t ina2xx_show_value(struct device *dev,
	struct device_attribute da, char buf)
	{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ina2xx_data *data = ina2xx_update_device(dev);

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

	return snprintf(buf, PAGE_SIZE, "%d\n",
	ina2xx_get_value(data, attr->index));
	}

	static ssize_t ina2xx_set_shunt(struct device *dev,
	struct device_attribute *da,
	const char *buf, size_t count)
	{
	struct ina2xx_data *data = ina2xx_update_device(dev);
	unsigned long val;
	int status;

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

	status = kstrtoul(buf, 10, &val);
	if (status < 0)
	return status;

	if (val == 0 \|\|
	/* Values greater than the calibration factor make no sense. */
	val > data->config->calibration_factor)
	return -EINVAL;

	mutex_lock(&data->update_lock);
	data->rshunt = val;
	status = ina2xx_calibrate(data);
	mutex_unlock(&data->update_lock);
	if (status < 0)
	return status;

	return count;
	}

	static ssize_t ina226_set_interval(struct device *dev,
	struct device_attribute *da,
	const char *buf, size_t count)
	{
	struct ina2xx_data *data = dev_get_drvdata(dev);
	unsigned long val;
	int status;

	status = kstrtoul(buf, 10, &val);
	if (status < 0)
	return status;

	if (val > INT_MAX \|\| val == 0)
	return -EINVAL;

	mutex_lock(&data->update_lock);
	data->curr_config = ina226_interval_to_reg(val,
	data->regs[INA2XX_CONFIG]);
	status = i2c_smbus_write_word_swapped(data->client,
	INA2XX_CONFIG,
	data->curr_config);

	ina226_set_update_interval(data);
	/* Make sure the next access re-reads all registers. */
	data->valid = 0;
	mutex_unlock(&data->update_lock);
	if (status < 0)
	return status;

	return count;
	}

	static ssize_t ina226_show_interval(struct device *dev,
	struct device_attribute da, char buf)
	{
	struct ina2xx_data *data = ina2xx_update_device(dev);

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

	/*
	* We don't use data->update_interval here as we want to display
	* the actual interval used by the chip and jiffies_to_msecs()
	* doesn't seem to be accurate enough.
	*/
	return snprintf(buf, PAGE_SIZE, "%d\n",
	ina226_reg_to_interval(data->regs[INA2XX_CONFIG]));
	}

	/* shunt voltage */
	static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
	INA2XX_SHUNT_VOLTAGE);

	/* bus voltage */
	static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
	INA2XX_BUS_VOLTAGE);

	/* calculated current */
	static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
	INA2XX_CURRENT);

	/* calculated power */
	static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
	INA2XX_POWER);

	/* shunt resistance */
	static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO \| S_IWUSR,
	ina2xx_show_value, ina2xx_set_shunt,
	INA2XX_CALIBRATION);

	/* update interval (ina226 only) */
	static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO \| S_IWUSR,
	ina226_show_interval, ina226_set_interval, 0);

	/* pointers to created device attributes */
	static struct attribute *ina2xx_attrs[] = {
	&sensor_dev_attr_in0_input.dev_attr.attr,
	&sensor_dev_attr_in1_input.dev_attr.attr,
	&sensor_dev_attr_curr1_input.dev_attr.attr,
	&sensor_dev_attr_power1_input.dev_attr.attr,
	&sensor_dev_attr_shunt_resistor.dev_attr.attr,
	NULL,
	};

	static const struct attribute_group ina2xx_group = {
	.attrs = ina2xx_attrs,
	};

	static struct attribute *ina226_attrs[] = {
	&sensor_dev_attr_update_interval.dev_attr.attr,
	NULL,
	};

	static const struct attribute_group ina226_group = {
	.attrs = ina226_attrs,
	};

	static int ina2xx_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct i2c_adapter *adapter = client->adapter;
	struct ina2xx_platform_data *pdata;
	struct device *dev = &client->dev;
	struct ina2xx_data *data;
	struct device *hwmon_dev;
	u32 val;
	int ret, group = 0;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
	return -ENODEV;

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

	if (dev_get_platdata(dev)) {
	pdata = dev_get_platdata(dev);
	data->rshunt = pdata->shunt_uohms;
	} else if (!of_property_read_u32(dev->of_node,
	"shunt-resistor", &val)) {
	data->rshunt = val;
	} else {
	data->rshunt = INA2XX_RSHUNT_DEFAULT;
	}

	/* set the device type */
	data->kind = id->driver_data;
	data->config = &ina2xx_config[data->kind];
	data->curr_config = data->config->config_default;
	data->client = client;

	/*
	* Ina226 has a variable update_interval. For ina219 we
	* use a constant value.
	*/
	if (data->kind == ina226)
	ina226_set_update_interval(data);
	else
	data->update_interval = HZ / INA2XX_CONVERSION_RATE;

	if (data->rshunt <= 0 \|\|
	data->rshunt > data->config->calibration_factor)
	return -ENODEV;

	ret = ina2xx_init(data);
	if (ret < 0) {
	dev_err(dev, "error configuring the device: %d\n", ret);
	return -ENODEV;
	}

	mutex_init(&data->update_lock);

	data->groups[group++] = &ina2xx_group;
	if (data->kind == ina226)
	data->groups[group++] = &ina226_group;

	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
	data, data->groups);
	if (IS_ERR(hwmon_dev))
	return PTR_ERR(hwmon_dev);

	dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
	id->name, data->rshunt);

	return 0;
	}

	static const struct i2c_device_id ina2xx_id[] = {
	{ "ina219", ina219 },
	{ "ina220", ina219 },
	{ "ina226", ina226 },
	{ "ina230", ina226 },
	{ "ina231", ina226 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, ina2xx_id);

	static struct i2c_driver ina2xx_driver = {
	.driver = {
	.name = "ina2xx",
	},
	.probe = ina2xx_probe,
	.id_table = ina2xx_id,
	};

	module_i2c_driver(ina2xx_driver);

	MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
	MODULE_DESCRIPTION("ina2xx driver");
	MODULE_LICENSE("GPL");