/*
   * Driver for the Texas Instruments / Burr Brown INA209
   * Bidirectional Current/Power Monitor
   *
   * Copyright (C) 2012 Guenter Roeck <linux@roeck-us.net>
   *
   * Derived from Ira W. Snyder's original driver submission
   *	Copyright (C) 2008 Paul Hays <Paul.Hays@cattail.ca>
   *	Copyright (C) 2008-2009 Ira W. Snyder <iws@ovro.caltech.edu>
   *
   * Aligned with ina2xx driver
   *	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.
   *
   * Datasheet:
   * http://www.ti.com/lit/gpn/ina209
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/err.h>
  #include <linux/slab.h>
  #include <linux/bug.h>
  #include <linux/i2c.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  
  #include <linux/platform_data/ina2xx.h>
  
  /* register definitions */
  #define INA209_CONFIGURATION		0x00
  #define INA209_STATUS			0x01
  #define INA209_STATUS_MASK		0x02
  #define INA209_SHUNT_VOLTAGE		0x03
  #define INA209_BUS_VOLTAGE		0x04
  #define INA209_POWER			0x05
  #define INA209_CURRENT			0x06
  #define INA209_SHUNT_VOLTAGE_POS_PEAK	0x07
  #define INA209_SHUNT_VOLTAGE_NEG_PEAK	0x08
  #define INA209_BUS_VOLTAGE_MAX_PEAK	0x09
  #define INA209_BUS_VOLTAGE_MIN_PEAK	0x0a
  #define INA209_POWER_PEAK		0x0b
  #define INA209_SHUNT_VOLTAGE_POS_WARN	0x0c
  #define INA209_SHUNT_VOLTAGE_NEG_WARN	0x0d
  #define INA209_POWER_WARN		0x0e
  #define INA209_BUS_VOLTAGE_OVER_WARN	0x0f
  #define INA209_BUS_VOLTAGE_UNDER_WARN	0x10
  #define INA209_POWER_OVER_LIMIT		0x11
  #define INA209_BUS_VOLTAGE_OVER_LIMIT	0x12
  #define INA209_BUS_VOLTAGE_UNDER_LIMIT	0x13
  #define INA209_CRITICAL_DAC_POS		0x14
  #define INA209_CRITICAL_DAC_NEG		0x15
  #define INA209_CALIBRATION		0x16
  
  #define INA209_REGISTERS		0x17
  
  #define INA209_CONFIG_DEFAULT		0x3c47	/* PGA=8, full range */
  #define INA209_SHUNT_DEFAULT		10000	/* uOhm */
  
  struct ina209_data {
  	struct i2c_client *client;
  
  	struct mutex update_lock;
  	bool valid;
  	unsigned long last_updated;	/* in jiffies */
  
  	u16 regs[INA209_REGISTERS];	/* All chip registers */
  
  	u16 config_orig;		/* Original configuration */
  	u16 calibration_orig;		/* Original calibration */
  	u16 update_interval;
  };
  
  static struct ina209_data *ina209_update_device(struct device *dev)
  {
  	struct ina209_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;
  	struct ina209_data *ret = data;
  	s32 val;
  	int i;
  
  	mutex_lock(&data->update_lock);
  
  	if (!data->valid ||
  	    time_after(jiffies, data->last_updated + data->update_interval)) {
  		for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
  			val = i2c_smbus_read_word_swapped(client, i);
  			if (val < 0) {
  				ret = ERR_PTR(val);
  				goto abort;
  			}
  			data->regs[i] = val;
  		}
  		data->last_updated = jiffies;
  		data->valid = true;
  	}
  abort:
  	mutex_unlock(&data->update_lock);
  	return ret;
  }
  
  /*
   * Read a value from a device register and convert it to the
   * appropriate sysfs units
   */
  static long ina209_from_reg(const u8 reg, const u16 val)
  {
  	switch (reg) {
  	case INA209_SHUNT_VOLTAGE:
  	case INA209_SHUNT_VOLTAGE_POS_PEAK:
  	case INA209_SHUNT_VOLTAGE_NEG_PEAK:
  	case INA209_SHUNT_VOLTAGE_POS_WARN:
  	case INA209_SHUNT_VOLTAGE_NEG_WARN:
  		/* LSB=10 uV. Convert to mV. */
  		return DIV_ROUND_CLOSEST(val, 100);
  
  	case INA209_BUS_VOLTAGE:
  	case INA209_BUS_VOLTAGE_MAX_PEAK:
  	case INA209_BUS_VOLTAGE_MIN_PEAK:
  	case INA209_BUS_VOLTAGE_OVER_WARN:
  	case INA209_BUS_VOLTAGE_UNDER_WARN:
  	case INA209_BUS_VOLTAGE_OVER_LIMIT:
  	case INA209_BUS_VOLTAGE_UNDER_LIMIT:
  		/* LSB=4 mV, last 3 bits unused */
  		return (val >> 3) * 4;
  
  	case INA209_CRITICAL_DAC_POS:
  		/* LSB=1 mV, in the upper 8 bits */
  		return val >> 8;
  
  	case INA209_CRITICAL_DAC_NEG:
  		/* LSB=1 mV, in the upper 8 bits */
  		return -1 * (val >> 8);
  
  	case INA209_POWER:
  	case INA209_POWER_PEAK:
  	case INA209_POWER_WARN:
  	case INA209_POWER_OVER_LIMIT:
  		/* LSB=20 mW. Convert to uW */
  		return val * 20 * 1000L;
  
  	case INA209_CURRENT:
  		/* LSB=1 mA (selected). Is in mA */
  		return val;
  	}
  
  	/* programmer goofed */
  	WARN_ON_ONCE(1);
  	return 0;
  }
  
  /*
   * Take a value and convert it to register format, clamping the value
   * to the appropriate range.
   */
  static int ina209_to_reg(u8 reg, u16 old, long val)
  {
  	switch (reg) {
  	case INA209_SHUNT_VOLTAGE_POS_WARN:
  	case INA209_SHUNT_VOLTAGE_NEG_WARN:
  		/* Limit to +- 320 mV, 10 uV LSB */
  		return clamp_val(val, -320, 320) * 100;
  
  	case INA209_BUS_VOLTAGE_OVER_WARN:
  	case INA209_BUS_VOLTAGE_UNDER_WARN:
  	case INA209_BUS_VOLTAGE_OVER_LIMIT:
  	case INA209_BUS_VOLTAGE_UNDER_LIMIT:
  		/*
  		 * Limit to 0-32000 mV, 4 mV LSB
  		 *
  		 * The last three bits aren't part of the value, but we'll
  		 * preserve them in their original state.
  		 */
  		return (DIV_ROUND_CLOSEST(clamp_val(val, 0, 32000), 4) << 3)
  		  | (old & 0x7);
  
  	case INA209_CRITICAL_DAC_NEG:
  		/*
  		 * Limit to -255-0 mV, 1 mV LSB
  		 * Convert the value to a positive value for the register
  		 *
  		 * The value lives in the top 8 bits only, be careful
  		 * and keep original value of other bits.
  		 */
  		return (clamp_val(-val, 0, 255) << 8) | (old & 0xff);
  
  	case INA209_CRITICAL_DAC_POS:
  		/*
  		 * Limit to 0-255 mV, 1 mV LSB
  		 *
  		 * The value lives in the top 8 bits only, be careful
  		 * and keep original value of other bits.
  		 */
  		return (clamp_val(val, 0, 255) << 8) | (old & 0xff);
  
  	case INA209_POWER_WARN:
  	case INA209_POWER_OVER_LIMIT:
  		/* 20 mW LSB */
  		return DIV_ROUND_CLOSEST(val, 20 * 1000);
  	}
  
  	/* Other registers are read-only, return access error */
  	return -EACCES;
  }
  
  static int ina209_interval_from_reg(u16 reg)
  {
  	return 68 >> (15 - ((reg >> 3) & 0x0f));
  }
  
  static u16 ina209_reg_from_interval(u16 config, long interval)
  {
  	int i, adc;
  
  	if (interval <= 0) {
  		adc = 8;
  	} else {
  		adc = 15;
  		for (i = 34 + 34 / 2; i; i >>= 1) {
  			if (i < interval)
  				break;
  			adc--;
  		}
  	}
  	return (config & 0xf807) | (adc << 3) | (adc << 7);
  }
  
  static ssize_t ina209_set_interval(struct device *dev,
  				   struct device_attribute *da,
  				   const char *buf, size_t count)
  {
  	struct ina209_data *data = ina209_update_device(dev);
  	long val;
  	u16 regval;
  	int ret;
  
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	ret = kstrtol(buf, 10, &val);
  	if (ret < 0)
  		return ret;
  
  	mutex_lock(&data->update_lock);
  	regval = ina209_reg_from_interval(data->regs[INA209_CONFIGURATION],
  					  val);
  	i2c_smbus_write_word_swapped(data->client, INA209_CONFIGURATION,
  				     regval);
  	data->regs[INA209_CONFIGURATION] = regval;
  	data->update_interval = ina209_interval_from_reg(regval);
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  static ssize_t ina209_show_interval(struct device *dev,
  				    struct device_attribute *da, char *buf)
  {
  	struct ina209_data *data = dev_get_drvdata(dev);
  
  	return snprintf(buf, PAGE_SIZE, "%d
  ", data->update_interval);
  }
  
  /*
   * History is reset by writing 1 into bit 0 of the respective peak register.
   * Since more than one peak register may be affected by the scope of a
   * reset_history attribute write, use a bit mask in attr->index to identify
   * which registers are affected.
   */
  static u16 ina209_reset_history_regs[] = {
  	INA209_SHUNT_VOLTAGE_POS_PEAK,
  	INA209_SHUNT_VOLTAGE_NEG_PEAK,
  	INA209_BUS_VOLTAGE_MAX_PEAK,
  	INA209_BUS_VOLTAGE_MIN_PEAK,
  	INA209_POWER_PEAK
  };
  
  static ssize_t ina209_reset_history(struct device *dev,
  				    struct device_attribute *da,
  				    const char *buf,
  				    size_t count)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	struct ina209_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;
  	u32 mask = attr->index;
  	long val;
  	int i, ret;
  
  	ret = kstrtol(buf, 10, &val);
  	if (ret < 0)
  		return ret;
  
  	mutex_lock(&data->update_lock);
  	for (i = 0; i < ARRAY_SIZE(ina209_reset_history_regs); i++) {
  		if (mask & (1 << i))
  			i2c_smbus_write_word_swapped(client,
  					ina209_reset_history_regs[i], 1);
  	}
  	data->valid = false;
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  static ssize_t ina209_set_value(struct device *dev,
  				struct device_attribute *da,
  				const char *buf,
  				size_t count)
  {
  	struct ina209_data *data = ina209_update_device(dev);
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int reg = attr->index;
  	long val;
  	int ret;
  
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	ret = kstrtol(buf, 10, &val);
  	if (ret < 0)
  		return ret;
  
  	mutex_lock(&data->update_lock);
  	ret = ina209_to_reg(reg, data->regs[reg], val);
  	if (ret < 0) {
  		count = ret;
  		goto abort;
  	}
  	i2c_smbus_write_word_swapped(data->client, reg, ret);
  	data->regs[reg] = ret;
  abort:
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  static ssize_t ina209_show_value(struct device *dev,
  				 struct device_attribute *da,
  				 char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	struct ina209_data *data = ina209_update_device(dev);
  	long val;
  
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	val = ina209_from_reg(attr->index, data->regs[attr->index]);
  	return snprintf(buf, PAGE_SIZE, "%ld
  ", val);
  }
  
  static ssize_t ina209_show_alarm(struct device *dev,
  				 struct device_attribute *da,
  				 char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	struct ina209_data *data = ina209_update_device(dev);
  	const unsigned int mask = attr->index;
  	u16 status;
  
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	status = data->regs[INA209_STATUS];
  
  	/*
  	 * All alarms are in the INA209_STATUS register. To avoid a long
  	 * switch statement, the mask is passed in attr->index
  	 */
  	return snprintf(buf, PAGE_SIZE, "%u
  ", !!(status & mask));
  }
  
  /* Shunt voltage, history, limits, alarms */
  static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina209_show_value, NULL,
  			  INA209_SHUNT_VOLTAGE);
  static SENSOR_DEVICE_ATTR(in0_input_highest, S_IRUGO, ina209_show_value, NULL,
  			  INA209_SHUNT_VOLTAGE_POS_PEAK);
  static SENSOR_DEVICE_ATTR(in0_input_lowest, S_IRUGO, ina209_show_value, NULL,
  			  INA209_SHUNT_VOLTAGE_NEG_PEAK);
  static SENSOR_DEVICE_ATTR(in0_reset_history, S_IWUSR, NULL,
  			  ina209_reset_history, (1 << 0) | (1 << 1));
  static SENSOR_DEVICE_ATTR(in0_max, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_SHUNT_VOLTAGE_POS_WARN);
  static SENSOR_DEVICE_ATTR(in0_min, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_SHUNT_VOLTAGE_NEG_WARN);
  static SENSOR_DEVICE_ATTR(in0_crit_max, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_CRITICAL_DAC_POS);
  static SENSOR_DEVICE_ATTR(in0_crit_min, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_CRITICAL_DAC_NEG);
  
  static SENSOR_DEVICE_ATTR(in0_min_alarm,  S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 11);
  static SENSOR_DEVICE_ATTR(in0_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 12);
  static SENSOR_DEVICE_ATTR(in0_crit_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 6);
  static SENSOR_DEVICE_ATTR(in0_crit_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 7);
  
  /* Bus voltage, history, limits, alarms */
  static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina209_show_value, NULL,
  			  INA209_BUS_VOLTAGE);
  static SENSOR_DEVICE_ATTR(in1_input_highest, S_IRUGO, ina209_show_value, NULL,
  			  INA209_BUS_VOLTAGE_MAX_PEAK);
  static SENSOR_DEVICE_ATTR(in1_input_lowest, S_IRUGO, ina209_show_value, NULL,
  			  INA209_BUS_VOLTAGE_MIN_PEAK);
  static SENSOR_DEVICE_ATTR(in1_reset_history, S_IWUSR, NULL,
  			  ina209_reset_history, (1 << 2) | (1 << 3));
  static SENSOR_DEVICE_ATTR(in1_max, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_BUS_VOLTAGE_OVER_WARN);
  static SENSOR_DEVICE_ATTR(in1_min, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_BUS_VOLTAGE_UNDER_WARN);
  static SENSOR_DEVICE_ATTR(in1_crit_max, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_BUS_VOLTAGE_OVER_LIMIT);
  static SENSOR_DEVICE_ATTR(in1_crit_min, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_BUS_VOLTAGE_UNDER_LIMIT);
  
  static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 14);
  static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 15);
  static SENSOR_DEVICE_ATTR(in1_crit_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 9);
  static SENSOR_DEVICE_ATTR(in1_crit_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 10);
  
  /* Power */
  static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina209_show_value, NULL,
  			  INA209_POWER);
  static SENSOR_DEVICE_ATTR(power1_input_highest, S_IRUGO, ina209_show_value,
  			  NULL, INA209_POWER_PEAK);
  static SENSOR_DEVICE_ATTR(power1_reset_history, S_IWUSR, NULL,
  			  ina209_reset_history, 1 << 4);
  static SENSOR_DEVICE_ATTR(power1_max, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_POWER_WARN);
  static SENSOR_DEVICE_ATTR(power1_crit, S_IRUGO | S_IWUSR, ina209_show_value,
  			  ina209_set_value, INA209_POWER_OVER_LIMIT);
  
  static SENSOR_DEVICE_ATTR(power1_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 13);
  static SENSOR_DEVICE_ATTR(power1_crit_alarm, S_IRUGO, ina209_show_alarm, NULL,
  			  1 << 8);
  
  /* Current */
  static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina209_show_value, NULL,
  			  INA209_CURRENT);
  
  static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
  			  ina209_show_interval, ina209_set_interval, 0);
  
  /*
   * Finally, construct an array of pointers to members of the above objects,
   * as required for sysfs_create_group()
   */
  static struct attribute *ina209_attrs[] = {
  	&sensor_dev_attr_in0_input.dev_attr.attr,
  	&sensor_dev_attr_in0_input_highest.dev_attr.attr,
  	&sensor_dev_attr_in0_input_lowest.dev_attr.attr,
  	&sensor_dev_attr_in0_reset_history.dev_attr.attr,
  	&sensor_dev_attr_in0_max.dev_attr.attr,
  	&sensor_dev_attr_in0_min.dev_attr.attr,
  	&sensor_dev_attr_in0_crit_max.dev_attr.attr,
  	&sensor_dev_attr_in0_crit_min.dev_attr.attr,
  	&sensor_dev_attr_in0_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_in0_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_in0_crit_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_in0_crit_min_alarm.dev_attr.attr,
  
  	&sensor_dev_attr_in1_input.dev_attr.attr,
  	&sensor_dev_attr_in1_input_highest.dev_attr.attr,
  	&sensor_dev_attr_in1_input_lowest.dev_attr.attr,
  	&sensor_dev_attr_in1_reset_history.dev_attr.attr,
  	&sensor_dev_attr_in1_max.dev_attr.attr,
  	&sensor_dev_attr_in1_min.dev_attr.attr,
  	&sensor_dev_attr_in1_crit_max.dev_attr.attr,
  	&sensor_dev_attr_in1_crit_min.dev_attr.attr,
  	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_in1_crit_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_in1_crit_min_alarm.dev_attr.attr,
  
  	&sensor_dev_attr_power1_input.dev_attr.attr,
  	&sensor_dev_attr_power1_input_highest.dev_attr.attr,
  	&sensor_dev_attr_power1_reset_history.dev_attr.attr,
  	&sensor_dev_attr_power1_max.dev_attr.attr,
  	&sensor_dev_attr_power1_crit.dev_attr.attr,
  	&sensor_dev_attr_power1_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_power1_crit_alarm.dev_attr.attr,
  
  	&sensor_dev_attr_curr1_input.dev_attr.attr,
  
  	&sensor_dev_attr_update_interval.dev_attr.attr,
  
  	NULL,
  };
  ATTRIBUTE_GROUPS(ina209);
  
  static void ina209_restore_conf(struct i2c_client *client,
  				struct ina209_data *data)
  {
  	/* Restore initial configuration */
  	i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
  				     data->config_orig);
  	i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
  				     data->calibration_orig);
  }
  
  static int ina209_init_client(struct i2c_client *client,
  			      struct ina209_data *data)
  {
  	struct ina2xx_platform_data *pdata = dev_get_platdata(&client->dev);
  	u32 shunt;
  	int reg;
  
  	reg = i2c_smbus_read_word_swapped(client, INA209_CALIBRATION);
  	if (reg < 0)
  		return reg;
  	data->calibration_orig = reg;
  
  	reg = i2c_smbus_read_word_swapped(client, INA209_CONFIGURATION);
  	if (reg < 0)
  		return reg;
  	data->config_orig = reg;
  
  	if (pdata) {
  		if (pdata->shunt_uohms <= 0)
  			return -EINVAL;
  		shunt = pdata->shunt_uohms;
  	} else if (!of_property_read_u32(client->dev.of_node, "shunt-resistor",
  					 &shunt)) {
  		if (shunt == 0)
  			return -EINVAL;
  	} else {
  		shunt = data->calibration_orig ?
  		  40960000 / data->calibration_orig : INA209_SHUNT_DEFAULT;
  	}
  
  	i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
  				     INA209_CONFIG_DEFAULT);
  	data->update_interval = ina209_interval_from_reg(INA209_CONFIG_DEFAULT);
  
  	/*
  	 * Calibrate current LSB to 1mA. Shunt is in uOhms.
  	 * See equation 13 in datasheet.
  	 */
  	i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
  				     clamp_val(40960000 / shunt, 1, 65535));
  
  	/* Clear status register */
  	i2c_smbus_read_word_swapped(client, INA209_STATUS);
  
  	return 0;
  }
  
  static int ina209_probe(struct i2c_client *client,
  			const struct i2c_device_id *id)
  {
  	struct i2c_adapter *adapter = client->adapter;
  	struct ina209_data *data;
  	struct device *hwmon_dev;
  	int ret;
  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
  		return -ENODEV;
  
  	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, data);
  	data->client = client;
  	mutex_init(&data->update_lock);
  
  	ret = ina209_init_client(client, data);
  	if (ret)
  		return ret;
  
  	hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
  							   client->name,
  							   data, ina209_groups);
  	if (IS_ERR(hwmon_dev)) {
  		ret = PTR_ERR(hwmon_dev);
  		goto out_restore_conf;
  	}
  
  	return 0;
  
  out_restore_conf:
  	ina209_restore_conf(client, data);
  	return ret;
  }
  
  static int ina209_remove(struct i2c_client *client)
  {
  	struct ina209_data *data = i2c_get_clientdata(client);
  
  	ina209_restore_conf(client, data);
  
  	return 0;
  }
  
  static const struct i2c_device_id ina209_id[] = {
  	{ "ina209", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, ina209_id);
  
  /* This is the driver that will be inserted */
  static struct i2c_driver ina209_driver = {
  	.class		= I2C_CLASS_HWMON,
  	.driver = {
  		.name	= "ina209",
  	},
  	.probe		= ina209_probe,
  	.remove		= ina209_remove,
  	.id_table	= ina209_id,
  };
  
  module_i2c_driver(ina209_driver);
  
  MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>, Paul Hays <Paul.Hays@cattail.ca>, Guenter Roeck <linux@roeck-us.net>");
  MODULE_DESCRIPTION("INA209 driver");
  MODULE_LICENSE("GPL");