Re: [PATCH v4 1/8] iio: adc: stm32-adc: fix channel sampling time init

Jonathan Cameron
2022-10-15T15:57:58Z

On Wed, 12 Oct 2022 16:21:58 +0200
Olivier Moysan <olivier.moysan@foss.st.com> wrote:

> Fix channel init for ADC generic channel bindings.
> In generic channel initialization, stm32_adc_smpr_init() is called to
> initialize channel sampling time. The "st,min-sample-time-ns" property
> is an optional property. If it is not defined, stm32_adc_smpr_init() is
> currently skipped.
> However stm32_adc_smpr_init() must always be called, to force a minimum
> sampling time for the internal channels, as the minimum sampling time is
> known. Make stm32_adc_smpr_init() call unconditional.
>
> Fixes: 796e5d0b1e9b ("iio: adc: stm32-adc: use generic binding for sample-time")
> Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>

So I'm crossing my fingers a little that this fix and the rest of the series can
go through different paths - looks like it should be clean.

Applied to the fixes-togreg branch of iio.git and marked for stable.

Thanks,

Jonathan

> ---
> drivers/iio/adc/stm32-adc.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index 6256977eb7f7..3cda529f081d 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -2086,18 +2086,19 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
> stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
> vin[1], scan_index, differential);
>
> + val = 0;
> ret = fwnode_property_read_u32(child, "st,min-sample-time-ns", &val);
> /* st,min-sample-time-ns is optional */
> - if (!ret) {
> - stm32_adc_smpr_init(adc, channels[scan_index].channel, val);
> - if (differential)
> - stm32_adc_smpr_init(adc, vin[1], val);
> - } else if (ret != -EINVAL) {
> + if (ret && ret != -EINVAL) {
> dev_err(&indio_dev->dev, "Invalid st,min-sample-time-ns property %d\n",
> ret);
> goto err;
> }
>
> + stm32_adc_smpr_init(adc, channels[scan_index].channel, val);
> + if (differential)
> + stm32_adc_smpr_init(adc, vin[1], val);
> +
> scan_index++;
> }
>