// SPDX-License-Identifier: GPL-2.0-only

  /*
   * 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 <lothar.felten@gmail.com>

   * Thanks to Jan Volkering

   */
  
  #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_device.h>

  #include <linux/of.h>

  #include <linux/delay.h>

  #include <linux/util_macros.h>

  #include <linux/regmap.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

  static struct regmap_config ina2xx_regmap_config = {
  	.reg_bits = 8,
  	.val_bits = 16,
  };

  enum ina2xx_ids { ina219, ina226 };

  struct ina2xx_config {
  	u16 config_default;

  	int calibration_value;

  	int registers;
  	int shunt_div;
  	int bus_voltage_shift;
  	int bus_voltage_lsb;	/* uV */

  	int power_lsb_factor;

  };

  struct ina2xx_data {

  	const struct ina2xx_config *config;

  	long rshunt;

  	long current_lsb_uA;
  	long power_lsb_uW;

  	struct mutex config_lock;
  	struct regmap *regmap;

  	const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];

  };

  static const struct ina2xx_config ina2xx_config[] = {
  	[ina219] = {
  		.config_default = INA219_CONFIG_DEFAULT,

  		.calibration_value = 4096,

  		.registers = INA219_REGISTERS,
  		.shunt_div = 100,
  		.bus_voltage_shift = 3,
  		.bus_voltage_lsb = 4000,

  		.power_lsb_factor = 20,

  	},
  	[ina226] = {
  		.config_default = INA226_CONFIG_DEFAULT,

  		.calibration_value = 2048,

  		.registers = INA226_REGISTERS,
  		.shunt_div = 400,
  		.bus_voltage_shift = 0,
  		.bus_voltage_lsb = 1250,

  		.power_lsb_factor = 25,

  	},
  };

  /*
   * 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);
  }

  /*
   * Return the new, shifted AVG field value of CONFIG register,
   * to use with regmap_update_bits
   */
  static u16 ina226_interval_to_reg(int interval)

  {
  	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 INA226_SHIFT_AVG(avg_bits);

  }

  /*
   * Calibration register is set to the best value, which eliminates
   * truncation errors on calculating current register in hardware.
   * According to datasheet (eq. 3) the best values are 2048 for
   * ina226 and 4096 for ina219. They are hardcoded as calibration_value.
   */

  static int ina2xx_calibrate(struct ina2xx_data *data)
  {

  	return regmap_write(data->regmap, INA2XX_CALIBRATION,
  			    data->config->calibration_value);

  }

  /*
   * Initialize the configuration and calibration registers.
   */
  static int ina2xx_init(struct ina2xx_data *data)

  {

  	int ret = regmap_write(data->regmap, INA2XX_CONFIG,
  			       data->config->config_default);

  	if (ret < 0)
  		return ret;

  	return ina2xx_calibrate(data);

  }

  static int ina2xx_read_reg(struct device *dev, int reg, unsigned int *regval)

  {
  	struct ina2xx_data *data = dev_get_drvdata(dev);

  	int ret, retry;

  	dev_dbg(dev, "Starting register %d read
  ", reg);

  	for (retry = 5; retry; retry--) {

  
  		ret = regmap_read(data->regmap, reg, regval);
  		if (ret < 0)
  			return ret;
  
  		dev_dbg(dev, "read %d, val = 0x%04x
  ", reg, *regval);

  
  		/*
  		 * 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.

  		 * We do that extra read of the calibration register if there
  		 * is some hint of a chip reset.

  		 */

  		if (*regval == 0) {
  			unsigned int cal;
  
  			ret = regmap_read(data->regmap, INA2XX_CALIBRATION,
  					  &cal);
  			if (ret < 0)
  				return ret;
  
  			if (cal == 0) {
  				dev_warn(dev, "chip not calibrated, reinitializing
  ");
  
  				ret = ina2xx_init(data);
  				if (ret < 0)
  					return ret;
  				/*
  				 * Let's make sure the power and current
  				 * registers have been updated before trying
  				 * again.
  				 */
  				msleep(INA2XX_MAX_DELAY);
  				continue;
  			}

  		}

  		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
  ");
  	return -ENODEV;
  }

  static int ina2xx_get_value(struct ina2xx_data *data, u8 reg,
  			    unsigned int regval)

  {

  	int val;

  
  	switch (reg) {
  	case INA2XX_SHUNT_VOLTAGE:

  		/* signed register */

  		val = DIV_ROUND_CLOSEST((s16)regval, data->config->shunt_div);

  		break;
  	case INA2XX_BUS_VOLTAGE:

  		val = (regval >> data->config->bus_voltage_shift)

  		  * data->config->bus_voltage_lsb;
  		val = DIV_ROUND_CLOSEST(val, 1000);

  		break;
  	case INA2XX_POWER:

  		val = regval * data->power_lsb_uW;

  		break;
  	case INA2XX_CURRENT:

  		/* signed register, result in mA */

  		val = (s16)regval * data->current_lsb_uA;

  		val = DIV_ROUND_CLOSEST(val, 1000);

  		break;

  	case INA2XX_CALIBRATION:

  		val = regval;

  		break;

  	default:
  		/* programmer goofed */
  		WARN_ON_ONCE(1);
  		val = 0;
  		break;
  	}
  
  	return val;
  }

  static ssize_t ina2xx_value_show(struct device *dev,

  				 struct device_attribute *da, char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

  	struct ina2xx_data *data = dev_get_drvdata(dev);
  	unsigned int regval;

  	int err = ina2xx_read_reg(dev, attr->index, &regval);
  
  	if (err < 0)
  		return err;

  	return snprintf(buf, PAGE_SIZE, "%d
  ",

  			ina2xx_get_value(data, attr->index, regval));

  }

  /*
   * In order to keep calibration register value fixed, the product
   * of current_lsb and shunt_resistor should also be fixed and equal
   * to shunt_voltage_lsb = 1 / shunt_div multiplied by 10^9 in order
   * to keep the scale.
   */
  static int ina2xx_set_shunt(struct ina2xx_data *data, long val)
  {
  	unsigned int dividend = DIV_ROUND_CLOSEST(1000000000,
  						  data->config->shunt_div);
  	if (val <= 0 || val > dividend)
  		return -EINVAL;
  
  	mutex_lock(&data->config_lock);
  	data->rshunt = val;
  	data->current_lsb_uA = DIV_ROUND_CLOSEST(dividend, val);
  	data->power_lsb_uW = data->config->power_lsb_factor *
  			     data->current_lsb_uA;
  	mutex_unlock(&data->config_lock);
  
  	return 0;
  }

  static ssize_t ina2xx_shunt_show(struct device *dev,
  				 struct device_attribute *da, char *buf)

  {
  	struct ina2xx_data *data = dev_get_drvdata(dev);
  
  	return snprintf(buf, PAGE_SIZE, "%li
  ", data->rshunt);
  }

  static ssize_t ina2xx_shunt_store(struct device *dev,

  				  struct device_attribute *da,
  				  const char *buf, size_t count)

  {

  	unsigned long val;
  	int status;

  	struct ina2xx_data *data = dev_get_drvdata(dev);

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

  	status = ina2xx_set_shunt(data, val);

  	if (status < 0)
  		return status;

  	return count;
  }

  static ssize_t ina226_interval_store(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;

  	status = regmap_update_bits(data->regmap, INA2XX_CONFIG,
  				    INA226_AVG_RD_MASK,
  				    ina226_interval_to_reg(val));

  	if (status < 0)
  		return status;
  
  	return count;
  }

  static ssize_t ina226_interval_show(struct device *dev,

  				    struct device_attribute *da, char *buf)
  {

  	struct ina2xx_data *data = dev_get_drvdata(dev);
  	int status;
  	unsigned int regval;

  	status = regmap_read(data->regmap, INA2XX_CONFIG, &regval);
  	if (status)
  		return status;

  	return snprintf(buf, PAGE_SIZE, "%d
  ", ina226_reg_to_interval(regval));

  }

  /* shunt voltage */

  static SENSOR_DEVICE_ATTR_RO(in0_input, ina2xx_value, INA2XX_SHUNT_VOLTAGE);

  
  /* bus voltage */

  static SENSOR_DEVICE_ATTR_RO(in1_input, ina2xx_value, INA2XX_BUS_VOLTAGE);

  
  /* calculated current */

  static SENSOR_DEVICE_ATTR_RO(curr1_input, ina2xx_value, INA2XX_CURRENT);

  
  /* calculated power */

  static SENSOR_DEVICE_ATTR_RO(power1_input, ina2xx_value, INA2XX_POWER);

  /* shunt resistance */

  static SENSOR_DEVICE_ATTR_RW(shunt_resistor, ina2xx_shunt, INA2XX_CALIBRATION);

  /* update interval (ina226 only) */

  static SENSOR_DEVICE_ATTR_RW(update_interval, ina226_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 device *dev = &client->dev;
  	struct ina2xx_data *data;
  	struct device *hwmon_dev;

  	u32 val;

  	int ret, group = 0;

  	enum ina2xx_ids chip;
  
  	if (client->dev.of_node)
  		chip = (enum ina2xx_ids)of_device_get_match_data(&client->dev);
  	else
  		chip = id->driver_data;

  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);

  	if (!data)
  		return -ENOMEM;

  	/* set the device type */

  	data->config = &ina2xx_config[chip];

  	mutex_init(&data->config_lock);

  	if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
  		struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
  
  		if (pdata)
  			val = pdata->shunt_uohms;
  		else
  			val = INA2XX_RSHUNT_DEFAULT;
  	}

  	ina2xx_set_shunt(data, val);

  	ina2xx_regmap_config.max_register = data->config->registers;
  
  	data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
  	if (IS_ERR(data->regmap)) {
  		dev_err(dev, "failed to allocate register map
  ");
  		return PTR_ERR(data->regmap);
  	}

  	ret = ina2xx_init(data);

  	if (ret < 0) {

  		dev_err(dev, "error configuring the device: %d
  ", ret);

  		return -ENODEV;
  	}

  	data->groups[group++] = &ina2xx_group;

  	if (chip == 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)
  ",

  		 client->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 const struct of_device_id __maybe_unused ina2xx_of_match[] = {

  	{
  		.compatible = "ti,ina219",
  		.data = (void *)ina219
  	},
  	{
  		.compatible = "ti,ina220",
  		.data = (void *)ina219
  	},
  	{
  		.compatible = "ti,ina226",
  		.data = (void *)ina226
  	},
  	{
  		.compatible = "ti,ina230",
  		.data = (void *)ina226
  	},
  	{
  		.compatible = "ti,ina231",
  		.data = (void *)ina226
  	},
  	{ },
  };
  MODULE_DEVICE_TABLE(of, ina2xx_of_match);

  static struct i2c_driver ina2xx_driver = {
  	.driver = {
  		.name	= "ina2xx",

  		.of_match_table = of_match_ptr(ina2xx_of_match),

  	},
  	.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");