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

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On Wed, 25 Aug 2021 17:25:14 +0200
Miquel Raynal <miquel.raynal@xxxxxxxxxxx> 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@xxxxxxxxxxx>
Odd no one did this before, but such is life ;)

Acked-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>

> ---
>  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;
>  




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