Reducing shunt and bus voltage range improves the accuracy, so allow altering the default settings.
Signed-off-by: Stefan Brüns <[email protected]> --- drivers/iio/adc/ina2xx-adc.c | 165 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 164 insertions(+), 1 deletion(-) diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c index d1678f886297..856409ecceb3 100644 --- a/drivers/iio/adc/ina2xx-adc.c +++ b/drivers/iio/adc/ina2xx-adc.c @@ -47,8 +47,10 @@ #define INA2XX_MAX_REGISTERS 8 /* settings - depend on use case */ -#define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */ +#define INA219_CONFIG_DEFAULT 0x399F /* PGA=1/8, BRNG=32V */ #define INA219_DEFAULT_IT 532 +#define INA219_DEFAULT_BRNG 32 +#define INA219_DEFAULT_PGA 125 /* 1000/8 */ #define INA226_CONFIG_DEFAULT 0x4327 #define INA226_DEFAULT_AVG 4 #define INA226_DEFAULT_IT 1110 @@ -61,6 +63,14 @@ */ #define INA2XX_MODE_MASK GENMASK(3, 0) +/* Gain for VShunt: 1/8 (default), 1/4, 1/2, 1 */ +#define INA219_PGA_MASK GENMASK(12, 11) +#define INA219_SHIFT_PGA(val) ((val) << 11) + +/* VBus range: 32V (default), 16V */ +#define INA219_BRNG_MASK BIT(13) +#define INA219_SHIFT_BRNG(val) ((val) << 13) + /* Averaging for VBus/VShunt/Power */ #define INA226_AVG_MASK GENMASK(11, 9) #define INA226_SHIFT_AVG(val) ((val) << 9) @@ -125,6 +135,8 @@ struct ina2xx_chip_info { int avg; int int_time_vbus; /* Bus voltage integration time uS */ int int_time_vshunt; /* Shunt voltage integration time uS */ + int range_vbus; /* Bus voltage maximum in V */ + int pga_gain_vshunt; /* Shunt voltage PGA gain */ bool allow_async_readout; }; @@ -351,6 +363,44 @@ static int ina219_set_int_time_vshunt(struct ina2xx_chip_info *chip, return 0; } +static int ina219_set_vbus_range(struct ina2xx_chip_info *chip, + unsigned int range, + unsigned int *config) +{ + if (range != 16 && range != 32) + return -EINVAL; + + chip->range_vbus = range; + + *config &= ~INA219_BRNG_MASK; + *config |= INA219_SHIFT_BRNG(range == 32 ? 1 : 0) & INA219_BRNG_MASK; + + return 0; +} + +static const int ina219_vshunt_gain_tab[] = { 125, 250, 500, 1000 }; + +static int ina219_set_vshunt_pga_gain(struct ina2xx_chip_info *chip, + unsigned int gain, + unsigned int *config) +{ + int bits; + + if (gain < 125 || gain > 1000) + return -EINVAL; + + bits = find_closest(gain, ina219_vshunt_gain_tab, + ARRAY_SIZE(ina219_vshunt_gain_tab)); + + chip->pga_gain_vshunt = ina219_vshunt_gain_tab[bits]; + bits = 3 - bits; + + *config &= ~INA219_PGA_MASK; + *config |= INA219_SHIFT_PGA(bits) & INA219_PGA_MASK; + + return 0; +} + static int ina2xx_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask) @@ -485,6 +535,92 @@ static ssize_t ina2xx_shunt_resistor_store(struct device *dev, return len; } +static ssize_t ina219_bus_voltage_range_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev)); + + return sprintf(buf, "%d\n", chip->range_vbus); +} + +static ssize_t ina219_bus_voltage_range_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev)); + unsigned long val; + unsigned int config, tmp; + int ret; + + ret = kstrtoul((const char *) buf, 10, &val); + if (ret) + return ret; + + mutex_lock(&chip->state_lock); + + ret = regmap_read(chip->regmap, INA2XX_CONFIG, &config); + if (ret) + goto err; + + tmp = config; + + ret = ina219_set_vbus_range(chip, val, &config); + + if (!ret && (tmp != config)) + ret = regmap_write(chip->regmap, INA2XX_CONFIG, config); + + if (!ret) + ret = len; +err: + mutex_unlock(&chip->state_lock); + + return ret; +} + +static ssize_t ina219_shunt_voltage_gain_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev)); + int vals[2] = { chip->pga_gain_vshunt, 1000 }; + + return iio_format_value(buf, IIO_VAL_FRACTIONAL, 1, vals); +} + +static ssize_t ina219_shunt_voltage_gain_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct ina2xx_chip_info *chip = iio_priv(dev_to_iio_dev(dev)); + unsigned int config, tmp; + int val, val_fract, ret; + + ret = iio_str_to_fixpoint(buf, 100, &val, &val_fract); + if (ret) + return ret; + + mutex_lock(&chip->state_lock); + + ret = regmap_read(chip->regmap, INA2XX_CONFIG, &config); + if (ret) + goto err; + + tmp = config; + + ret = ina219_set_vshunt_pga_gain(chip, val * 1000 + val_fract, &config); + + if (!ret && (tmp != config)) + ret = regmap_write(chip->regmap, INA2XX_CONFIG, config); + + if (!ret) + ret = len; +err: + mutex_unlock(&chip->state_lock); + + return ret; +} + #define INA2XX_CHAN(_type, _index, _address) { \ .type = (_type), \ .address = (_address), \ @@ -698,6 +834,15 @@ static IIO_CONST_ATTR_NAMED(ina226_integration_time_available, integration_time_available, "0.000140 0.000204 0.000332 0.000588 0.001100 0.002116 0.004156 0.008244"); +/* INA219/220 Bus voltage range */ +static IIO_CONST_ATTR_NAMED(ina219_bus_voltage_range_available, + in_bus_voltage_range_available, + "16 32"); + +/* INA219/220 Shunt voltage PGA gain */ +static IIO_CONST_ATTR_NAMED(ina219_shunt_voltage_gain_available, + in_shunt_voltage_gain_available, + "0.125 0.25 0.5 1"); static IIO_DEVICE_ATTR(in_allow_async_readout, S_IRUGO | S_IWUSR, ina2xx_allow_async_readout_show, @@ -707,9 +852,25 @@ static IIO_DEVICE_ATTR(in_shunt_resistor, S_IRUGO | S_IWUSR, ina2xx_shunt_resistor_show, ina2xx_shunt_resistor_store, 0); +static IIO_DEVICE_ATTR_NAMED(ina219_bus_voltage_range, + in_bus_voltage_range, + S_IRUGO | S_IWUSR, + ina219_bus_voltage_range_show, + ina219_bus_voltage_range_store, 0); + +static IIO_DEVICE_ATTR_NAMED(ina219_shunt_voltage_gain, + in_shunt_voltage_gain, + S_IRUGO | S_IWUSR, + ina219_shunt_voltage_gain_show, + ina219_shunt_voltage_gain_store, 0); + static struct attribute *ina219_attributes[] = { &iio_dev_attr_in_allow_async_readout.dev_attr.attr, &iio_const_attr_ina219_integration_time_available.dev_attr.attr, + &iio_dev_attr_ina219_bus_voltage_range.dev_attr.attr, + &iio_const_attr_ina219_bus_voltage_range_available.dev_attr.attr, + &iio_dev_attr_ina219_shunt_voltage_gain.dev_attr.attr, + &iio_const_attr_ina219_shunt_voltage_gain_available.dev_attr.attr, &iio_dev_attr_in_shunt_resistor.dev_attr.attr, NULL, }; @@ -809,6 +970,8 @@ static int ina2xx_probe(struct i2c_client *client, 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(chip, INA219_DEFAULT_BRNG, &val); + ina219_set_vshunt_pga_gain(chip, INA219_DEFAULT_PGA, &val); } ret = ina2xx_init(chip, val); -- 2.12.0
