Commit eeca1114 authored by Jonas Rebmann's avatar Jonas Rebmann Committed by Guenter Roeck
Browse files

hwmon: (ina2xx) Shift INA234 shunt and current registers 



The INA219 has the lowest three bits of the bus voltage register
zero-reserved, the bus_voltage_shift ina2xx_config field was introduced
to accommodate for that.

The INA234 has four bits of the bus voltage, of the shunt voltage, and
of the current registers zero-reserved but the latter two were
implemented by choosing a 16x higher shunt_div instead of a separate
field specifying a bit shift.

This is possible because shunt voltage and current are divided by
shunt_div, hence a 16x higher shunt_div results in a 16x smaller LSB for
both the shunt voltage and the current register, perfectly accounting
for the missing bit shift.

For consistency and correctness, account for the reserved bits via
shunt_voltage_shift and current_shift configuration fields as already
done for voltage registers and use the conversion constants given in the
INA234 datasheet.

Signed-off-by: default avatarJonas Rebmann <jre@pengutronix.de>
Link: https://lore.kernel.org/r/20260303-ina234-shift-v1-2-318c33ac4480@pengutronix.de


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 932ca40b

drivers/hwmon/ina2xx.c

+19 −3
Original line number Diff line number Diff line
@@ -135,9 +135,11 @@ struct ina2xx_config { 
	bool has_update_interval;

	int calibration_value;

	int shunt_div;

	int shunt_voltage_shift;

	int bus_voltage_shift;

	int bus_voltage_lsb;	/* uV */

	int power_lsb_factor;

	int current_shift;

};



struct ina2xx_data {
@@ -156,59 +158,69 @@ static const struct ina2xx_config ina2xx_config[] = { 
		.config_default = INA219_CONFIG_DEFAULT,

		.calibration_value = 4096,

		.shunt_div = 100,

		.shunt_voltage_shift = 0,

		.bus_voltage_shift = 3,

		.bus_voltage_lsb = 4000,

		.power_lsb_factor = 20,

		.has_alerts = false,

		.has_ishunt = false,

		.has_power_average = false,

		.current_shift = 0,

		.has_update_interval = false,

	},

	[ina226] = {

		.config_default = INA226_CONFIG_DEFAULT,

		.calibration_value = 2048,

		.shunt_div = 400,

		.shunt_voltage_shift = 0,

		.bus_voltage_shift = 0,

		.bus_voltage_lsb = 1250,

		.power_lsb_factor = 25,

		.has_alerts = true,

		.has_ishunt = false,

		.has_power_average = false,

		.current_shift = 0,

		.has_update_interval = true,

	},

	[ina234] = {

		.config_default = INA226_CONFIG_DEFAULT,

		.calibration_value = 2048,

		.shunt_div = 400, /* 2.5 µV/LSB raw ADC reading from INA2XX_SHUNT_VOLTAGE */

		.shunt_div = 25, /* 2.5 µV/LSB raw ADC reading from INA2XX_SHUNT_VOLTAGE */

		.shunt_voltage_shift = 4,

		.bus_voltage_shift = 4,

		.bus_voltage_lsb = 25600,

		.power_lsb_factor = 32,

		.has_alerts = true,

		.has_ishunt = false,

		.has_power_average = false,

		.current_shift = 4,

		.has_update_interval = true,

	},

	[ina260] = {

		.config_default = INA260_CONFIG_DEFAULT,

		.shunt_div = 400,

		.shunt_voltage_shift = 0,

		.bus_voltage_shift = 0,

		.bus_voltage_lsb = 1250,

		.power_lsb_factor = 8,

		.has_alerts = true,

		.has_ishunt = true,

		.has_power_average = false,

		.current_shift = 0,

		.has_update_interval = true,

	},

	[sy24655] = {

		.config_default = SY24655_CONFIG_DEFAULT,

		.calibration_value = 4096,

		.shunt_div = 400,

		.shunt_voltage_shift = 0,

		.bus_voltage_shift = 0,

		.bus_voltage_lsb = 1250,

		.power_lsb_factor = 25,

		.has_alerts = true,

		.has_ishunt = false,

		.has_power_average = true,

		.current_shift = 0,

		.has_update_interval = false,

	},

};
@@ -262,7 +274,8 @@ static int ina2xx_get_value(struct ina2xx_data *data, u8 reg, 
	switch (reg) {

	case INA2XX_SHUNT_VOLTAGE:

		/* signed register */

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

		val = (s16)regval >> data->config->shunt_voltage_shift;

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

		break;

	case INA2XX_BUS_VOLTAGE:

		val = (regval >> data->config->bus_voltage_shift) *
@@ -274,7 +287,8 @@ static int ina2xx_get_value(struct ina2xx_data *data, u8 reg, 
		break;

	case INA2XX_CURRENT:

		/* signed register, result in mA */

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

		val = ((s16)regval >> data->config->current_shift) *

		  data->current_lsb_uA;

		val = DIV_ROUND_CLOSEST(val, 1000);

		break;

	case INA2XX_CALIBRATION:
@@ -368,6 +382,7 @@ static u16 ina226_alert_to_reg(struct ina2xx_data *data, int reg, long val) 
	case INA2XX_SHUNT_VOLTAGE:

		val = clamp_val(val, 0, SHRT_MAX * data->config->shunt_div);

		val *= data->config->shunt_div;

		val <<= data->config->shunt_voltage_shift;

		return clamp_val(val, 0, SHRT_MAX);

	case INA2XX_BUS_VOLTAGE:

		val = clamp_val(val, 0, 200000);
@@ -382,6 +397,7 @@ static u16 ina226_alert_to_reg(struct ina2xx_data *data, int reg, long val) 
		val = clamp_val(val, INT_MIN / 1000, INT_MAX / 1000);

		/* signed register, result in mA */

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

		val <<= data->config->current_shift;

		return clamp_val(val, SHRT_MIN, SHRT_MAX);

	default:

		/* programmer goofed */