On Sat, 21 Oct 2017 18:54:01 +0100 Jonathan Cameron <jic23@xxxxxxxxxx> wrote: > On Tue, 17 Oct 2017 15:15:43 +0200 > Fabrice Gasnier <fabrice.gasnier@xxxxxx> wrote: > > > STM32H7 ADC channels may be configured either as single-ended or > > differential. > > Add 'st,adc-diff-channels' property to support differential channels. > > Differential channels are defined as a pair of positive and negative > > inputs: vinp & vinn. > > > > Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx> > Hmm. Fair enough. Sometimes we support both types of channels > and leave it to userspace, but in many cases that makes little sense > - particularly if like I think is going on here, we aren't combining channels > that can be separately read but rather the negative pin is simply unused > when we are in single channel mode... (did I understand that right?) I clearly didn't understand. This is same as other devices in that we are picking a pair from the channels that can otherwise be used as single end channels. (I think). For this binding I think I'd like to see an example added showing how this works... Thanks, Jonathan > > Jonathan > > > --- > > Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt > > index 48bfcaa3..c3c8de1 100644 > > --- a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt > > +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt > > @@ -62,6 +62,12 @@ Required properties: > > - st,adc-channels: List of single-ended channels muxed for this ADC. > > It can have up to 16 channels on stm32f4 or 20 channels on stm32h7, numbered > > from 0 to 15 or 19 (resp. for in0..in15 or in0..in19). > > +- st,adc-diff-channels: List of differential channels muxed for this ADC. > > + Depending on part used, some channels can be configured as differential > > + instead of single-ended (e.g. stm32h7). List here positive and negative > > + inputs pairs as <vinp vinn>, <vinp vinn>,... vinp and vinn are numbered > > + from 0 to 19 on stm32h7) > > + Note: At least one of "st,adc-channels" or "st,adc-diff-channels" is required. > > - #io-channel-cells = <1>: See the IIO bindings section "IIO consumers" in > > Documentation/devicetree/bindings/iio/iio-bindings.txt > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
