Re: [PATCH-vs-togreg v2 1/2] iio: ina2xx-adc: update the CALIB. register when RShunt changes

[Marc Titinger]

On 20/03/2016 12:24, Jonathan Cameron wrote:
> On 14/03/16 10:20, 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>
> > ---
> >   v2 of http://www.spinics.net/lists/linux-iio/msg23402.html:
> >
> > 	- remove unnecessary line insertions
> > 	- cleanup leftover unused variable (build warning)
> > 	- patch 2/2 is unchanged (see v1)
> Err, can't find it for some reason.

sorry, it's here http://www.spinics.net/lists/linux-iio/msg23401.html
or here: pwclient get 8565821

BR,
Marc.

> Anyhow, applied this one to the togreg branch of iio.git - pushed
> out as testing for the autobuilders to play with it.
>
> Thanks,
>
> Jonathan
> > ---
> >   drivers/iio/adc/ina2xx-adc.c | 39 ++++++++++++++++++++++++---------------
> >   1 file changed, 24 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
> > index 65909d5..4e56fe3 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;
> >   }
> >
> > @@ -602,24 +624,11 @@ static const struct iio_info ina2xx_info = {
> >   /* Initialize the configuration and calibration registers. */
> >   static int ina2xx_init(struct ina2xx_chip_info *chip, unsigned int config)
> >   {
> > -	u16 regval;
> > -	int ret;
> > -
> > -	ret = regmap_write(chip->regmap, INA2XX_CONFIG, config);
> > +	int ret = regmap_write(chip->regmap, INA2XX_CONFIG, 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,