INA 238 linux 驱动

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for Texas Instruments INA238 power monitor chip
 * Datasheet: https://www.ti.com/product/ina238
 *
 * Copyright (C) 2021 Nathan Rossi 
 */

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#include 

/* INA238 register definitions */
#define INA238_CONFIG 0x0
#define INA238_ADC_CONFIG 0x1
#define INA238_SHUNT_CALIBRATION 0x2
#define INA238_SHUNT_VOLTAGE 0x4
#define INA238_BUS_VOLTAGE 0x5
#define INA238_DIE_TEMP 0x6
#define INA238_CURRENT 0x7
#define INA238_POWER 0x8
#define INA238_DIAG_ALERT 0xb
#define INA238_SHUNT_OVER_VOLTAGE 0xc
#define INA238_SHUNT_UNDER_VOLTAGE 0xd
#define INA238_BUS_OVER_VOLTAGE 0xe
#define INA238_BUS_UNDER_VOLTAGE 0xf
#define INA238_TEMP_LIMIT 0x10
#define INA238_POWER_LIMIT 0x11
#define INA238_DEVICE_ID 0x3f

#define INA238_CONFIG_ADCRANGE BIT(4)

#define INA238_DIAG_ALERT_TMPOL BIT(7)
#define INA238_DIAG_ALERT_SHNTOL BIT(6)
#define INA238_DIAG_ALERT_SHNTUL BIT(5)
#define INA238_DIAG_ALERT_BUSOL BIT(4)
#define INA238_DIAG_ALERT_BUSUL BIT(3)
#define INA238_DIAG_ALERT_POL BIT(2)

#define INA238_REGISTERS 0x11

#define INA238_RSHUNT_DEFAULT 10000 /* uOhm */

/* Default configuration of device on reset. */
#define INA238_CONFIG_DEFAULT 0
/* 16 sample averaging, 1052us conversion time, continuous mode */
#define INA238_ADC_CONFIG_DEFAULT 0xfb6a
/* Configure alerts to be based on averaged value (SLOWALERT) */
#define INA238_DIAG_ALERT_DEFAULT 0x2000
/*
 * This driver uses a fixed calibration value in order to scale current/power
 * based on a fixed shunt resistor value. This allows for conversion within the
 * device to avoid integer limits whilst current/power accuracy is scaled
 * relative to the shunt resistor value within the driver. This is similar to
 * how the ina2xx driver handles current/power scaling.
 *
 * The end result of this is that increasing shunt values (from a fixed 20 mOhm
 * shunt) increase the effective current/power accuracy whilst limiting the
 * range and decreasing shunt values decrease the effective accuracy but
 * increase the range.
 *
 * The value of the Current register is calculated given the following:
 *   Current (A) = (shunt voltage register * 5) * calibration / 81920
 *
 * The maximum shunt voltage is 163.835 mV (0x7fff, ADC_RANGE = 0, gain = 4).
 * With the maximum current value of 0x7fff and a fixed shunt value results in
 * a calibration value of 16384 (0x4000).
 *
 *   0x7fff = (0x7fff * 5) * calibration / 81920
 *   calibration = 0x4000
 *
 * Equivalent calibration is applied for the Power register (maximum value for
 * bus voltage is 102396.875 mV, 0x7fff), where the maximum power that can
 * occur is ~16776192 uW (register value 0x147a8):
 *
 * This scaling means the resulting values for Current and Power registers need
 * to be scaled by the difference between the fixed shunt resistor and the
 * actual shunt resistor:
 *
 *  shunt = 0x4000 / (819.2 * 10^6) / 0.001 = 20000 uOhms (with 1mA/lsb)
 *
 *  Current (mA) = register value * 20000 / rshunt / 4 * gain
 *  Power (W) = 0.2 * register value * 20000 / rshunt / 4 * gain
 */
#define INA238_CALIBRATION_VALUE 16384
#define INA238_FIXED_SHUNT 20000

#define INA238_SHUNT_VOLTAGE_LSB 5  /* 5 uV/lsb */
#define INA238_BUS_VOLTAGE_LSB 3125 /* 3.125 mV/lsb */
#define INA238_DIE_TEMP_LSB 125     /* 125 mC/lsb */

static struct regmap_config ina238_regmap_config = {
    .max_register = INA238_REGISTERS,
    .reg_bits = 8,
    .val_bits = 16,
};

struct ina238_data {
  struct i2c_client *client;
  struct mutex config_lock;
  struct regmap *regmap;
  u32 rshunt;
  int gain;
};

static int ina238_read_reg24(const struct i2c_client *client, u8 reg,
                             u32 *val) {
  u8 data[3];
  int err;

  /* 24-bit register read */
  err = i2c_smbus_read_i2c_block_data(client, reg, 3, data);
  if (err < 0)
    return err;
  if (err != 3)
    return -EIO;
  *val = (data[0] << 16) | (data[1] << 8) | data[2];

  return 0;
}

static int ina238_read_in(struct device *dev, u32 attr, int channel,
                          long *val) {
  struct ina238_data *data = dev_get_drvdata(dev);
  int reg, mask;
  int regval;
  int err;

  switch (channel) {
  case 0:
    switch (attr) {
    case hwmon_in_input:
      reg = INA238_SHUNT_VOLTAGE;
      break;
    case hwmon_in_max:
      reg = INA238_SHUNT_OVER_VOLTAGE;
      break;
    case hwmon_in_min:
      reg = INA238_SHUNT_UNDER_VOLTAGE;
      break;
    case hwmon_in_max_alarm:
      reg = INA238_DIAG_ALERT;
      mask = INA238_DIAG_ALERT_SHNTOL;
      break;
    case hwmon_in_min_alarm:
      reg = INA238_DIAG_ALERT;
      mask = INA238_DIAG_ALERT_SHNTUL;
      break;
    default:
      return -EOPNOTSUPP;
    }
    break;
  case 1:
    switch (attr) {
    case hwmon_in_input:
      reg = INA238_BUS_VOLTAGE;
      break;
    case hwmon_in_max:
      reg = INA238_BUS_OVER_VOLTAGE;
      break;
    case hwmon_in_min:
      reg = INA238_BUS_UNDER_VOLTAGE;
      break;
    case hwmon_in_max_alarm:
      reg = INA238_DIAG_ALERT;
      mask = INA238_DIAG_ALERT_BUSOL;
      break;
    case hwmon_in_min_alarm:
      reg = INA238_DIAG_ALERT;
      mask = INA238_DIAG_ALERT_BUSUL;
      break;
    default:
      return -EOPNOTSUPP;
    }
    break;
  default:
    return -EOPNOTSUPP;
  }

  err = regmap_read(data->regmap, reg, &regval);
  if (err < 0)
    return err;

  switch (attr) {
  case hwmon_in_input:
  case hwmon_in_max:
  case hwmon_in_min:
    /* signed register, value in mV */
    regval = (s16)regval;
    if (channel == 0)
      /* gain of 1 -> LSB / 4 */
      *val =
          (regval * INA238_SHUNT_VOLTAGE_LSB) / (1000 * (4 - data->gain + 1));
    else
      *val = (regval * INA238_BUS_VOLTAGE_LSB) / 1000;
    break;
  case hwmon_in_max_alarm:
  case hwmon_in_min_alarm:
    *val = !!(regval & mask);
    break;
  }

  return 0;
}

static int ina238_write_in(struct device *dev, u32 attr, int channel,
                           long val) {
  struct ina238_data *data = dev_get_drvdata(dev);
  int regval;

  if (attr != hwmon_in_max && attr != hwmon_in_min)
    return -EOPNOTSUPP;

  /* convert decimal to register value */
  switch (channel) {
  case 0:
    /* signed value, clamp to max range +/-163 mV */
    regval = clamp_val(val, -163, 163);
    regval = (regval * 1000 * (4 - data->gain + 1)) / INA238_SHUNT_VOLTAGE_LSB;
    regval = clamp_val(regval, S16_MIN, S16_MAX);

    switch (attr) {
    case hwmon_in_max:
      return regmap_write(data->regmap, INA238_SHUNT_OVER_VOLTAGE, regval);
    case hwmon_in_min:
      return regmap_write(data->regmap, INA238_SHUNT_UNDER_VOLTAGE, regval);
    default:
      return -EOPNOTSUPP;
    }
  case 1:
    /* signed value, positive values only. Clamp to max 102.396 V */
    regval = clamp_val(val, 0, 102396);
    regval = (regval * 1000) / INA238_BUS_VOLTAGE_LSB;
    regval = clamp_val(regval, 0, S16_MAX);

    switch (attr) {
    case hwmon_in_max:
      return regmap_write(data->regmap, INA238_BUS_OVER_VOLTAGE, regval);
    case hwmon_in_min:
      return regmap_write(data->regmap, INA238_BUS_UNDER_VOLTAGE, regval);
    default:
      return -EOPNOTSUPP;
    }
  default:
    return -EOPNOTSUPP;
  }
}

static int ina238_read_current(struct device *dev, u32 attr, long *val) {
  struct ina238_data *data = dev_get_drvdata(dev);
  int regval;
  int err;

  switch (attr) {
  case hwmon_curr_input:
    err = regmap_read(data->regmap, INA238_CURRENT, &regval);
    if (err < 0)
      return err;

    /* Signed register, fixed 1mA current lsb. result in mA */
    *val = div_s64((s16)regval * INA238_FIXED_SHUNT * data->gain,
                   data->rshunt * 4);
    break;
  default:
    return -EOPNOTSUPP;
  }

  return 0;
}

static int ina238_read_power(struct device *dev, u32 attr, long *val) {
  struct ina238_data *data = dev_get_drvdata(dev);
  long long power;
  int regval;
  int err;

  switch (attr) {
  case hwmon_power_input:
    err = ina238_read_reg24(data->client, INA238_POWER, &regval);
    if (err)
      return err;

    /* Fixed 1mA lsb, scaled by 1000000 to have result in uW */
    power = div_u64(regval * 1000ULL * INA238_FIXED_SHUNT * data->gain,
                    20 * data->rshunt);
    /* Clamp value to maximum value of long */
    *val = clamp_val(power, 0, LONG_MAX);
    break;
  case hwmon_power_max:
    err = regmap_read(data->regmap, INA238_POWER_LIMIT, &regval);
    if (err)
      return err;

    /*
     * Truncated 24-bit compare register, lower 8-bits are
     * truncated. Same conversion to/from uW as POWER register.
     */
    power = div_u64((regval << 8) * 1000ULL * INA238_FIXED_SHUNT * data->gain,
                    20 * data->rshunt);
    /* Clamp value to maximum value of long */
    *val = clamp_val(power, 0, LONG_MAX);
    break;
  case hwmon_power_max_alarm:
    err = regmap_read(data->regmap, INA238_DIAG_ALERT, &regval);
    if (err)
      return err;

    *val = !!(regval & INA238_DIAG_ALERT_POL);
    break;
  default:
    return -EOPNOTSUPP;
  }

  return 0;
}

static int ina238_write_power(struct device *dev, u32 attr, long val) {
  struct ina238_data *data = dev_get_drvdata(dev);
  long regval;

  if (attr != hwmon_power_max)
    return -EOPNOTSUPP;

  /*
   * Unsigned postive values. Compared against the 24-bit power register,
   * lower 8-bits are truncated. Same conversion to/from uW as POWER
   * register.
   */
  regval = clamp_val(val, 0, LONG_MAX);
  regval = div_u64(val * 20ULL * data->rshunt,
                   1000ULL * INA238_FIXED_SHUNT * data->gain);
  regval = clamp_val(regval >> 8, 0, U16_MAX);

  return regmap_write(data->regmap, INA238_POWER_LIMIT, regval);
}

static int ina238_read_temp(struct device *dev, u32 attr, long *val) {
  struct ina238_data *data = dev_get_drvdata(dev);
  int regval;
  int err;

  switch (attr) {
  case hwmon_temp_input:
    err = regmap_read(data->regmap, INA238_DIE_TEMP, &regval);
    if (err)
      return err;

    /* Signed, bits 15-4 of register, result in mC */
    *val = ((s16)regval >> 4) * INA238_DIE_TEMP_LSB;
    break;
  case hwmon_temp_max:
    err = regmap_read(data->regmap, INA238_TEMP_LIMIT, &regval);
    if (err)
      return err;

    /* Signed, bits 15-4 of register, result in mC */
    *val = ((s16)regval >> 4) * INA238_DIE_TEMP_LSB;
    break;
  case hwmon_temp_max_alarm:
    err = regmap_read(data->regmap, INA238_DIAG_ALERT, &regval);
    if (err)
      return err;

    *val = !!(regval & INA238_DIAG_ALERT_TMPOL);
    break;
  default:
    return -EOPNOTSUPP;
  }

  return 0;
}

static int ina238_write_temp(struct device *dev, u32 attr, long val) {
  struct ina238_data *data = dev_get_drvdata(dev);
  int regval;

  if (attr != hwmon_temp_max)
    return -EOPNOTSUPP;

  /* Signed, bits 15-4 of register */
  regval = (val / INA238_DIE_TEMP_LSB) << 4;
  regval = clamp_val(regval, S16_MIN, S16_MAX) & 0xfff0;

  return regmap_write(data->regmap, INA238_TEMP_LIMIT, regval);
}

static int ina238_read(struct device *dev, enum hwmon_sensor_types type,
                       u32 attr, int channel, long *val) {
  switch (type) {
  case hwmon_in:
    return ina238_read_in(dev, attr, channel, val);
  case hwmon_curr:
    return ina238_read_current(dev, attr, val);
  case hwmon_power:
    return ina238_read_power(dev, attr, val);
  case hwmon_temp:
    return ina238_read_temp(dev, attr, val);
  default:
    return -EOPNOTSUPP;
  }
  return 0;
}

static int ina238_write(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long val) {
  struct ina238_data *data = dev_get_drvdata(dev);
  int err;

  mutex_lock(&data->config_lock);

  switch (type) {
  case hwmon_in:
    err = ina238_write_in(dev, attr, channel, val);
    break;
  case hwmon_power:
    err = ina238_write_power(dev, attr, val);
    break;
  case hwmon_temp:
    err = ina238_write_temp(dev, attr, val);
    break;
  default:
    err = -EOPNOTSUPP;
    break;
  }

  mutex_unlock(&data->config_lock);
  return err;
}

static umode_t ina238_is_visible(const void *drvdata,
                                 enum hwmon_sensor_types type, u32 attr,
                                 int channel) {
  switch (type) {
  case hwmon_in:
    switch (attr) {
    case hwmon_in_input:
    case hwmon_in_max_alarm:
    case hwmon_in_min_alarm:
      return 0444;
    case hwmon_in_max:
    case hwmon_in_min:
      return 0644;
    default:
      return 0;
    }
  case hwmon_curr:
    switch (attr) {
    case hwmon_curr_input:
      return 0444;
    default:
      return 0;
    }
  case hwmon_power:
    switch (attr) {
    case hwmon_power_input:
    case hwmon_power_max_alarm:
      return 0444;
    case hwmon_power_max:
      return 0644;
    default:
      return 0;
    }
  case hwmon_temp:
    switch (attr) {
    case hwmon_temp_input:
    case hwmon_temp_max_alarm:
      return 0444;
    case hwmon_temp_max:
      return 0644;
    default:
      return 0;
    }
  default:
    return 0;
  }
}

#define INA238_HWMON_IN_CONFIG                                                 \
  (HWMON_I_INPUT | HWMON_I_MAX | HWMON_I_MAX_ALARM | HWMON_I_MIN |             \
   HWMON_I_MIN_ALARM)

static const struct hwmon_channel_info *const ina238_info[] = {
    HWMON_CHANNEL_INFO(in,
                       /* 0: shunt voltage */
                       INA238_HWMON_IN_CONFIG,
                       /* 1: bus voltage */
                       INA238_HWMON_IN_CONFIG),
    HWMON_CHANNEL_INFO(curr,
                       /* 0: current through shunt */
                       HWMON_C_INPUT),
    HWMON_CHANNEL_INFO(power,
                       /* 0: power */
                       HWMON_P_INPUT | HWMON_P_MAX | HWMON_P_MAX_ALARM),
    HWMON_CHANNEL_INFO(temp,
                       /* 0: die temperature */
                       HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_ALARM),
    NULL};

static const struct hwmon_ops ina238_hwmon_ops = {
    .is_visible = ina238_is_visible,
    .read = ina238_read,
    .write = ina238_write,
};

static const struct hwmon_chip_info ina238_chip_info = {
    .ops = &ina238_hwmon_ops,
    .info = ina238_info,
};

static int ina238_probe(struct i2c_client *client) {
  struct ina2xx_platform_data *pdata = dev_get_platdata(&client->dev);
  struct device *dev = &client->dev;
  struct device *hwmon_dev;
  struct ina238_data *data;
  int config;
  int ret;

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

  data->client = client;
  mutex_init(&data->config_lock);

  data->regmap = devm_regmap_init_i2c(client, &ina238_regmap_config);
  if (IS_ERR(data->regmap)) {
    dev_err(dev, "failed to allocate register map\n");
    return PTR_ERR(data->regmap);
  }

  /* load shunt value */
  data->rshunt = INA238_RSHUNT_DEFAULT;
  if (device_property_read_u32(dev, "shunt-resistor", &data->rshunt) < 0 &&
      pdata)
    data->rshunt = pdata->shunt_uohms;
  if (data->rshunt == 0) {
    dev_err(dev, "invalid shunt resister value %u\n", data->rshunt);
    return -EINVAL;
  }

  /* load shunt gain value */
  if (device_property_read_u32(dev, "ti,shunt-gain", &data->gain) < 0)
    data->gain = 4; /* Default of ADCRANGE = 0 */
  if (data->gain != 1 && data->gain != 4) {
    dev_err(dev, "invalid shunt gain value %u\n", data->gain);
    return -EINVAL;
  }

  /* Setup CONFIG register */
  config = INA238_CONFIG_DEFAULT;
  if (data->gain == 1)
    config |= INA238_CONFIG_ADCRANGE; /* ADCRANGE = 1 is /1 */
  ret = regmap_write(data->regmap, INA238_CONFIG, config);
  if (ret < 0) {
    dev_err(dev, "error configuring the device: %d\n", ret);
    return -ENODEV;
  }

  /* Setup ADC_CONFIG register */
  ret =
      regmap_write(data->regmap, INA238_ADC_CONFIG, INA238_ADC_CONFIG_DEFAULT);
  if (ret < 0) {
    dev_err(dev, "error configuring the device: %d\n", ret);
    return -ENODEV;
  }

  /* Setup SHUNT_CALIBRATION register with fixed value */
  ret = regmap_write(data->regmap, INA238_SHUNT_CALIBRATION,
                     INA238_CALIBRATION_VALUE);
  if (ret < 0) {
    dev_err(dev, "error configuring the device: %d\n", ret);
    return -ENODEV;
  }

  /* Setup alert/alarm configuration */
  ret =
      regmap_write(data->regmap, INA238_DIAG_ALERT, INA238_DIAG_ALERT_DEFAULT);
  if (ret < 0) {
    dev_err(dev, "error configuring the device: %d\n", ret);
    return -ENODEV;
  }

  hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
                                                   &ina238_chip_info, NULL);
  if (IS_ERR(hwmon_dev))
    return PTR_ERR(hwmon_dev);

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

  return 0;
}

static const struct i2c_device_id ina238_id[] = {{"ina238", 0}, {}};
MODULE_DEVICE_TABLE(i2c, ina238_id);

static const struct of_device_id __maybe_unused ina238_of_match[] = {
    {.compatible = "ti,ina238"},
    {},
};
MODULE_DEVICE_TABLE(of, ina238_of_match);

static struct i2c_driver ina238_driver = {
    .class = I2C_CLASS_HWMON,
    .driver =
        {
            .name = "ina238",
            .of_match_table = of_match_ptr(ina238_of_match),
        },
    .probe = ina238_probe,
    .id_table = ina238_id,
};

module_i2c_driver(ina238_driver);

MODULE_AUTHOR("Nathan Rossi ");
MODULE_DESCRIPTION("ina238 driver");
MODULE_LICENSE("GPL");

6.5 kernel

但是也支持其他的linux 版本,可以使用,芯片的功能完整

hwon 和 iio 的概念 好像 做了细分