On 03/11/2016 08:52 AM, Marc Titinger wrote:
> The user (or an init script) may setup RShunt via sysfs after the
> driver was initialized, for instance based on the EEPROM contents
> of a modular probe. The calibration register must be set accordingly.
>
> Signed-off-by: Marc Titinger <marc.titinger@xxxxxxxxxxxx>
> ---
> tested with BeagleBone-black and BayLibre-acme.
> ---
> drivers/iio/adc/ina2xx-adc.c | 36 +++++++++++++++++++++++++-----------
> 1 file changed, 25 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
> index 65909d5..e5ac120 100644
> --- a/drivers/iio/adc/ina2xx-adc.c
> +++ b/drivers/iio/adc/ina2xx-adc.c
> @@ -350,6 +350,23 @@ static ssize_t ina2xx_allow_async_readout_store(struct device *dev,
> return len;
> }
>
> +/*
> + * Set current LSB to 1mA, shunt is in uOhms
> + * (equation 13 in datasheet). We hardcode a Current_LSB
> + * of 1.0 x10-6. The only remaining parameter is RShunt.
> + * There is no need to expose the CALIBRATION register
> + * to the user for now. But we need to reset this register
> + * if the user updates RShunt after driver init, e.g upon
> + * reading an EEPROM/Probe-type value.
> + */
> +static int ina2xx_set_calibration(struct ina2xx_chip_info *chip)
> +{
> + u16 regval = DIV_ROUND_CLOSEST(chip->config->calibration_factor,
> + chip->shunt_resistor);
> +
> + return regmap_write(chip->regmap, INA2XX_CALIBRATION, regval);
> +}
> +
> static int set_shunt_resistor(struct ina2xx_chip_info *chip, unsigned int val)
> {
> if (val <= 0 || val > chip->config->calibration_factor)
> @@ -385,6 +402,11 @@ static ssize_t ina2xx_shunt_resistor_store(struct device *dev,
> if (ret)
> return ret;
>
> + /* Update the Calibration register */
> + ret = ina2xx_set_calibration(chip);
> + if (ret)
> + return ret;
> +
> return len;
> }
>
> @@ -599,6 +621,8 @@ static const struct iio_info ina2xx_info = {
> .debugfs_reg_access = ina2xx_debug_reg,
> };
>
> +
> +
?
> /* Initialize the configuration and calibration registers. */
> static int ina2xx_init(struct ina2xx_chip_info *chip, unsigned int config)
> {
> @@ -609,17 +633,7 @@ static int ina2xx_init(struct ina2xx_chip_info *chip, unsigned int config)
> if (ret)
> return ret;
>
> - /*
> - * Set current LSB to 1mA, shunt is in uOhms
> - * (equation 13 in datasheet). We hardcode a Current_LSB
> - * of 1.0 x10-6. The only remaining parameter is RShunt.
> - * There is no need to expose the CALIBRATION register
> - * to the user for now.
> - */
> - regval = DIV_ROUND_CLOSEST(chip->config->calibration_factor,
> - chip->shunt_resistor);
> -
> - return regmap_write(chip->regmap, INA2XX_CALIBRATION, regval);
> + return ina2xx_set_calibration(chip);
> }
>
> static int ina2xx_probe(struct i2c_client *client,
>
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