[PATCH v3] iio: adc: ina2xx: add INA236 support

Chuang Zhu
2026-03-15T18:23:38Z

The calibration divisor is not directly specified in the datasheet, but can be calculated:

I = Current_LSB * Current
Current = ShuntVoltage * CAL / calibration_divisor
CAL = 0.00512 / (Current_LSB * Rshunt)
ShuntVoltage = Vshunt / ShuntVoltage_LSB

=> I = (0.00512 / (calibration_divisor*ShuntVoltage_LSB)) * (Vshunt / Rshunt)

Ohm's law, I = Vshunt / Rshunt
=> 0.00512 / (calibration_divisor*ShuntVoltage_LSB) = 1

ShuntVoltage_LSB = 2.5 uV = 0.0000025 V
=> calibration_divisor = 2048

Signed-off-by: Chuang Zhu <git@chuang.cz>
---
drivers/iio/adc/ina2xx-adc.c | 57 ++++++++++++++++++++++++++++++------
1 file changed, 48 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
index 857e1b69d6cd..6a4ee833d12c 100644
--- a/drivers/iio/adc/ina2xx-adc.c
+++ b/drivers/iio/adc/ina2xx-adc.c
@@ -121,7 +121,7 @@ static const struct regmap_config ina2xx_regmap_config = {
.volatile_reg = ina2xx_is_volatile_reg,
};

-enum ina2xx_ids { ina219, ina226 };
+enum ina2xx_ids { ina219, ina226, ina236 };

struct ina2xx_config {
const char *name;
@@ -175,6 +175,16 @@ static const struct ina2xx_config ina2xx_config[] = {
.power_lsb_factor = 25,
.chip_id = ina226,
},
+ [ina236] = {
+ .name = "ina236",
+ .config_default = INA226_CONFIG_DEFAULT,
+ .calibration_value = 2048,
+ .shunt_voltage_lsb = 2500,
+ .bus_voltage_shift = 0,
+ .bus_voltage_lsb = 1600,
+ .power_lsb_factor = 32,
+ .chip_id = ina236,
+ },
};

static int ina2xx_read_raw(struct iio_dev *indio_dev,
@@ -499,20 +509,26 @@ static int ina2xx_write_raw(struct iio_dev *indio_dev,
break;

case IIO_CHAN_INFO_INT_TIME:
- if (chip->config->chip_id == ina226) {
+ switch (chip->config->chip_id) {
+ case ina226:
+ case ina236:
if (chan->address == INA2XX_SHUNT_VOLTAGE)
ret = ina226_set_int_time_vshunt(chip, val2,
&tmp);
else
ret = ina226_set_int_time_vbus(chip, val2,
&tmp);
- } else {
+ break;
+ case ina219:
if (chan->address == INA2XX_SHUNT_VOLTAGE)
ret = ina219_set_int_time_vshunt(chip, val2,
&tmp);
else
ret = ina219_set_int_time_vbus(chip, val2,
&tmp);
+ break;
+ default:
+ ret = -EINVAL;
}
break;

@@ -727,14 +743,20 @@ static int ina2xx_conversion_ready(struct iio_dev *indio_dev)
* For now, we do an extra read of the MASK_ENABLE register (INA226)
* resp. the BUS_VOLTAGE register (INA219).
*/
- if (chip->config->chip_id == ina226) {
+ switch (chip->config->chip_id) {
+ case ina226:
+ case ina236:
ret = regmap_read(chip->regmap,
INA226_MASK_ENABLE, &alert);
alert &= INA226_CVRF;
- } else {
+ break;
+ case ina219:
ret = regmap_read(chip->regmap,
INA2XX_BUS_VOLTAGE, &alert);
alert &= INA219_CNVR;
+ break;
+ default:
+ ret = -EINVAL;
}

if (ret < 0)
@@ -998,16 +1020,22 @@ static int ina2xx_probe(struct i2c_client *client)
/* Patch the current config register with default. */
val = chip->config->config_default;

- if (type == ina226) {
+ switch (type) {
+ case ina226:
+ case ina236:
ina226_set_average(chip, INA226_DEFAULT_AVG, &val);
ina226_set_int_time_vbus(chip, INA226_DEFAULT_IT, &val);
ina226_set_int_time_vshunt(chip, INA226_DEFAULT_IT, &val);
- } else {
+ break;
+ case ina219:
chip->avg = 1;
ina219_set_int_time_vbus(chip, INA219_DEFAULT_IT, &val);
ina219_set_int_time_vshunt(chip, INA219_DEFAULT_IT, &val);
ina219_set_vbus_range_denom(chip, INA219_DEFAULT_BRNG, &val);
ina219_set_vshunt_pga_gain(chip, INA219_DEFAULT_PGA, &val);
+ break;
+ default:
+ return -EINVAL;
}

ret = ina2xx_init(chip, val);
@@ -1017,14 +1045,20 @@ static int ina2xx_probe(struct i2c_client *client)
}

indio_dev->modes = INDIO_DIRECT_MODE;
- if (type == ina226) {
+ switch (type) {
+ case ina226:
+ case ina236:
indio_dev->channels = ina226_channels;
indio_dev->num_channels = ARRAY_SIZE(ina226_channels);
indio_dev->info = &ina226_info;
- } else {
+ break;
+ case ina219:
indio_dev->channels = ina219_channels;
indio_dev->num_channels = ARRAY_SIZE(ina219_channels);
indio_dev->info = &ina219_info;
+ break;
+ default:
+ return -EINVAL;
}
indio_dev->name = id ? id->name : chip->config->name;

@@ -1057,6 +1091,7 @@ static const struct i2c_device_id ina2xx_id[] = {
{ "ina226", ina226 },
{ "ina230", ina226 },
{ "ina231", ina226 },
+ { "ina236", ina236 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ina2xx_id);
@@ -1082,6 +1117,10 @@ static const struct of_device_id ina2xx_of_match[] = {
.compatible = "ti,ina231",
.data = (void *)ina226
},
+ {
+ .compatible = "ti,ina236",
+ .data = (void *)ina236
+ },
{ }
};
MODULE_DEVICE_TABLE(of, ina2xx_of_match);
--
2.51.2