From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Cameron Subject: Re: [PATCH 1/3] dt-bindings: iio: adc: stm32: add support for diff channels Date: Sat, 21 Oct 2017 18:54:01 +0100 Message-ID: <20171021185401.529f2eb2@archlinux> References: <1508246145-19417-1-git-send-email-fabrice.gasnier@st.com> <1508246145-19417-2-git-send-email-fabrice.gasnier@st.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1508246145-19417-2-git-send-email-fabrice.gasnier@st.com> Sender: linux-kernel-owner@vger.kernel.org To: Fabrice Gasnier Cc: robh+dt@kernel.org, linux@armlinux.org.uk, mark.rutland@arm.com, mcoquelin.stm32@gmail.com, alexandre.torgue@st.com, lars@metafoo.de, knaack.h@gmx.de, pmeerw@pmeerw.net, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, benjamin.gaignard@linaro.org, benjamin.gaignard@st.com List-Id: devicetree@vger.kernel.org On Tue, 17 Oct 2017 15:15:43 +0200 Fabrice Gasnier 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 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?) 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 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 >