Re: [PATCH 36/40] iio: adc: ti_am335x_adc: Add the scale information

Jonathan Cameron
2021-08-30T14:20:46Z

On Wed, 25 Aug 2021 17:25:14 +0200
Miquel Raynal <miquel.raynal@bootlin.com> wrote:

> Without the scale, the values returned to the user are just a picture of
> the input voltage against the full scale range of the ADC. We need to
> provide the actual conversion factor to get milli-Volts values.
>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Odd no one did this before, but such is life ;)

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
> drivers/iio/adc/ti_am335x_adc.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index d4619fd6fd54..f644898b47dd 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -417,6 +417,7 @@ static int tiadc_channel_init(struct device *dev, struct iio_dev *indio_dev,
> chan->indexed = 1;
> chan->channel = adc_dev->channel_line[i];
> chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
> + chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
> chan->datasheet_name = chan_name_ain[chan->channel];
> chan->scan_index = i;
> chan->scan_type.sign = 'u';
> @@ -441,6 +442,23 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
> unsigned long timeout;
> int ret;
>
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + break;
> + case IIO_CHAN_INFO_SCALE:
> + switch (chan->type) {
> + case IIO_VOLTAGE:
> + *val = 1800;
> + *val2 = chan->scan_type.realbits;
> + return IIO_VAL_FRACTIONAL_LOG2;
> + default:
> + return -EINVAL;
> + }
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> if (iio_buffer_enabled(indio_dev))
> return -EBUSY;
>