[Linux-stm32] [PATCH v3 2/2] iio: adc: stm32-adc: skip adc-channels setup if none is present

[Jonathan Cameron]

On Thu, 4 May 2023 13:41:24 +0200
Olivier MOYSAN <olivier.moysan at foss.st.com> wrote:

> Hi Sean,
> 
> Thanks for your update
> You can add my: Reviewed-by: Olivier Moysan <olivier.moysan at foss.st.com>
Please keep RB on a separate line as it makes it easier for scripts to find
it (e.g. b4)  I wasn't clear on whether RB applied to both patches or just
this one, so I went with safe option and only applied it to this one.

Both patches applied to the fixes-togreg branch of iio.git

Thanks,

Jonathan

> 
> BRs
> Olivier
> 
> On 5/3/23 18:20, Sean Nyekjaer wrote:
> > If only adc differential channels are defined driver will fail with
> > stm32-adc: probe of 48003000.adc:adc at 0 failed with error -22
> > 
> > Fix this by skipping the initialization if no channels are defined.
> > 
> > This applies only to the legacy way of initializing adc channels.
> > 
> > Fixes: d7705f35448a ("iio: adc: stm32-adc: convert to device properties")
> > Signed-off-by: Sean Nyekjaer <sean at geanix.com>
> > ---
> > Changes since v1:
> > - Ignore extra channel for timestamps in PIO mode
> > - Use single ended count in channel creation (Thanks Olivier Moysan)
> > 
> > Changes since v2:
> > - Avoid calling device_property_read_u32_array with num_se 0 (Thanks Olivier Moysan)
> > 
> >   drivers/iio/adc/stm32-adc.c | 42 ++++++++++++++++++++-----------------
> >   1 file changed, 23 insertions(+), 19 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> > index 14524c1b5583..f7613efb870d 100644
> > --- a/drivers/iio/adc/stm32-adc.c
> > +++ b/drivers/iio/adc/stm32-adc.c
> > @@ -2038,6 +2038,7 @@ static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
> >   	struct stm32_adc_diff_channel diff[STM32_ADC_CH_MAX];
> >   	struct device *dev = &indio_dev->dev;
> >   	u32 num_diff = adc->num_diff;
> > +	int num_se = nchans - num_diff;
> >   	int size = num_diff * sizeof(*diff) / sizeof(u32);
> >   	int scan_index = 0, ret, i, c;
> >   	u32 smp = 0, smps[STM32_ADC_CH_MAX], chans[STM32_ADC_CH_MAX];
> > @@ -2064,29 +2065,32 @@ static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
> >   			scan_index++;
> >   		}
> >   	}
> > -
> > -	ret = device_property_read_u32_array(dev, "st,adc-channels", chans,
> > -					     nchans);
> > -	if (ret)
> > -		return ret;
> > -
> > -	for (c = 0; c < nchans; c++) {
> > -		if (chans[c] >= adc_info->max_channels) {
> > -			dev_err(&indio_dev->dev, "Invalid channel %d\n",
> > -				chans[c]);
> > -			return -EINVAL;
> > +	if (num_se > 0) {
> > +		ret = device_property_read_u32_array(dev, "st,adc-channels", chans, num_se);
> > +		if (ret) {
> > +			dev_err(&indio_dev->dev, "Failed to get st,adc-channels %d\n", ret);
> > +			return ret;
> >   		}
> >   
> > -		/* Channel can't be configured both as single-ended & diff */
> > -		for (i = 0; i < num_diff; i++) {
> > -			if (chans[c] == diff[i].vinp) {
> > -				dev_err(&indio_dev->dev, "channel %d misconfigured\n",	chans[c]);
> > +		for (c = 0; c < num_se; c++) {
> > +			if (chans[c] >= adc_info->max_channels) {
> > +				dev_err(&indio_dev->dev, "Invalid channel %d\n",
> > +					chans[c]);
> >   				return -EINVAL;
> >   			}
> > +
> > +			/* Channel can't be configured both as single-ended & diff */
> > +			for (i = 0; i < num_diff; i++) {
> > +				if (chans[c] == diff[i].vinp) {
> > +					dev_err(&indio_dev->dev, "channel %d misconfigured\n",
> > +						chans[c]);
> > +					return -EINVAL;
> > +				}
> > +			}
> > +			stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
> > +						chans[c], 0, scan_index, false);
> > +			scan_index++;
> >   		}
> > -		stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
> > -					chans[c], 0, scan_index, false);
> > -		scan_index++;
> >   	}
> >   
> >   	if (adc->nsmps > 0) {
> > @@ -2307,7 +2311,7 @@ static int stm32_adc_chan_fw_init(struct iio_dev *indio_dev, bool timestamping)
> >   
> >   	if (legacy)
> >   		ret = stm32_adc_legacy_chan_init(indio_dev, adc, channels,
> > -						 num_channels);
> > +						 timestamping ? num_channels - 1 : num_channels);
> >   	else
> >   		ret = stm32_adc_generic_chan_init(indio_dev, adc, channels);
> >   	if (ret < 0)