From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Cameron Subject: Re: [PATCH v6 8/9] dt-bindings: mux-adg792a: document devicetree bindings for ADG792A/G mux Date: Sun, 1 Jan 2017 11:00:30 +0000 Message-ID: References: <1480493823-21462-1-git-send-email-peda@axentia.se> <1480493823-21462-9-git-send-email-peda@axentia.se> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1480493823-21462-9-git-send-email-peda@axentia.se> Sender: linux-kernel-owner@vger.kernel.org To: Peter Rosin , linux-kernel@vger.kernel.org Cc: Wolfram Sang , Rob Herring , Mark Rutland , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Jonathan Corbet , Arnd Bergmann , Greg Kroah-Hartman , linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-iio@vger.kernel.org, linux-doc@vger.kernel.org List-Id: devicetree@vger.kernel.org On 30/11/16 08:17, Peter Rosin wrote: > Analog Devices ADG792A/G is a triple 4:1 mux. > > Signed-off-by: Peter Rosin Few comments inline. Worth adding anything about the gpio (output pins) to the binding at this stage as well? Would certainly be nice to support them. Jonathan > --- > .../devicetree/bindings/misc/mux-adg792a.txt | 64 ++++++++++++++++++++++ > 1 file changed, 64 insertions(+) > create mode 100644 Documentation/devicetree/bindings/misc/mux-adg792a.txt > > diff --git a/Documentation/devicetree/bindings/misc/mux-adg792a.txt b/Documentation/devicetree/bindings/misc/mux-adg792a.txt > new file mode 100644 > index 000000000000..4677f9ab1c55 > --- /dev/null > +++ b/Documentation/devicetree/bindings/misc/mux-adg792a.txt > @@ -0,0 +1,64 @@ > +Bindings for Analog Devices ADG792A/G Triple 4:1 Multiplexers > + > +Required properties: > +- compatible : "adi,adg792a" or "adi,adg792g" > +- #mux-control-cells : <0> if parallel, or <1> if not. > +* Standard mux-controller bindings as decribed in mux-controller.txt > + > +Optional properties: > +- adi,parallel : if present, the three muxes are bound together with a single > + mux controller, controlling all three muxes in parallel. > +- adi,idle-state : if present, array of states the three mux controllers will > + have when idle (or, if parallel, a single idle-state). Hmm. These are actually a policy decision. As only one policy will make sense for a given set of hardware probably fine to have it in here I guess. Might be worth adding a note to say this though. > + > +Mux controller states 0 through 3 correspond to signals A through D in the > +datasheet. Mux controller states 4 and 5 are only available as possible idle > +states. State 4 represents that nothing is connected, and state 5 represents > +that the mux controller keeps the mux in its previously selected state during > +the idle period. State 5 is the default idle state. I'm never a great fan of magic numbers. Can we represent this more cleanly by breaking it into multiple properties? Optional: adi,idle-switch-to-channel : switch to this channel when idle. adi,idle-high-impedance : the nothing connected state? If neither present leaves it in previous state? > + > +Example: > + > + /* three independent mux controllers (of which one is used) */ > + &i2c0 { > + mux: adg792a@50 { > + compatible = "adi,adg792a"; > + reg = <0x50>; > + #mux-control-cells = <1>; > + }; > + }; > + > + adc-mux { > + compatible = "iio-mux"; > + io-channels = <&adc 0>; > + io-channel-names = "parent"; > + > + mux-controls = <&mux 1>; > + > + channels = "sync-1", "", "out"; > + }; > + > + > + /* > + * Three parallel muxes with one mux controller, useful e.g. if > + * the adc is differential, thus needing two signals to be muxed > + * simultaneously for correct operation. > + */ > + &i2c0 { > + pmux: adg792a@50 { > + compatible = "adi,adg792a"; > + reg = <0x50>; > + #mux-control-cells = <0>; > + adi,parallel; > + }; > + }; > + > + diff-adc-mux { > + compatible = "iio-mux"; > + io-channels = <&adc 0>; > + io-channel-names = "parent"; > + > + mux-controls = <&pmux>; > + > + channels = "sync-1", "", "out"; > + }; >