On Wed, 17 Nov 2021 00:37:46 +0300
Evgeny Boger <boger@xxxxxxxxxxxxxx> wrote:
> Both the charging and discharging currents on AXP22x are stored as
> 12-bit integers, in accordance with the datasheet.
> It's also confirmed by vendor BSP (axp20x_adc.c:axp22_icharge_to_mA).
>
> The scale factor of 0.5 is never mentioned in datasheet, nor in the
> vendor source code. I think it was here to compensate for
> erroneous addition bit in register width.
>
> Tested on custom A40i+AXP221s board with external ammeter as
> a reference.
>
> Signed-off-by: Evgeny Boger <boger@xxxxxxxxxxxxxx>
I know Quentin has moved on from Bootlin, so looking for input from Chen-Yu Tsai
for these as I have no idea :)
I have pinged Quentin as well on off chance he still wants to take a look.
Jonathan
> ---
>
> Notes:
> Changes from v1:
> - return scale factor of 1 as IIO_VAL_INT, not IIO_VAL_INT_PLUS_MICRO
> - get rid of unused variable
>
> drivers/iio/adc/axp20x_adc.c | 18 +++---------------
> 1 file changed, 3 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/iio/adc/axp20x_adc.c b/drivers/iio/adc/axp20x_adc.c
> index 3e0c0233b431..df99f1365c39 100644
> --- a/drivers/iio/adc/axp20x_adc.c
> +++ b/drivers/iio/adc/axp20x_adc.c
> @@ -251,19 +251,8 @@ static int axp22x_adc_raw(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan, int *val)
> {
> struct axp20x_adc_iio *info = iio_priv(indio_dev);
> - int size;
>
> - /*
> - * N.B.: Unlike the Chinese datasheets tell, the charging current is
> - * stored on 12 bits, not 13 bits. Only discharging current is on 13
> - * bits.
> - */
> - if (chan->type == IIO_CURRENT && chan->channel == AXP22X_BATT_DISCHRG_I)
> - size = 13;
> - else
> - size = 12;
> -
> - *val = axp20x_read_variable_width(info->regmap, chan->address, size);
> + *val = axp20x_read_variable_width(info->regmap, chan->address, 12);
> if (*val < 0)
> return *val;
>
> @@ -386,9 +375,8 @@ static int axp22x_adc_scale(struct iio_chan_spec const *chan, int *val,
> return IIO_VAL_INT_PLUS_MICRO;
>
> case IIO_CURRENT:
> - *val = 0;
> - *val2 = 500000;
> - return IIO_VAL_INT_PLUS_MICRO;
> + *val = 1;
> + return IIO_VAL_INT;
>
> case IIO_TEMP:
> *val = 100;
