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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: Jonas Rebmann <jre@pengutronix.de>
Link: https://lore.kernel.org/r/20260303-ina234-shift-v1-2-318c33ac4480@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Jonas Rebmann 2026-03-03 12:07:02 +01:00 committed by Guenter Roeck
parent 932ca40b10
commit eeca1114d1
1 changed files with 19 additions and 3 deletions
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22
drivers/hwmon/ina2xx.c
View File

@ -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 */