Messages in this thread | | | Subject | Re: [RFC 1/2] dt-bindings: add mmio-based syscon mux controller DT bindings | From | Steve Longerbeam <> | Date | Thu, 13 Apr 2017 18:03:43 -0700 |
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On 04/13/2017 08:48 AM, Philipp Zabel wrote: > This adds device tree binding documentation for mmio-based syscon > multiplexers controlled by a single bitfield in a syscon register > range.
Nice! (you beat me to it, I was about to embark on this myself :)
Looks good to me, just some minor comments below.
> > Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> > --- > Documentation/devicetree/bindings/mux/mmio-mux.txt | 56 ++++++++++++++++++++++ > 1 file changed, 56 insertions(+) > create mode 100644 Documentation/devicetree/bindings/mux/mmio-mux.txt > > diff --git a/Documentation/devicetree/bindings/mux/mmio-mux.txt b/Documentation/devicetree/bindings/mux/mmio-mux.txt > new file mode 100644 > index 0000000000000..11d96f5d98583 > --- /dev/null > +++ b/Documentation/devicetree/bindings/mux/mmio-mux.txt > @@ -0,0 +1,56 @@ > +MMIO bitfield-based multiplexer controller bindings > + > +Define a syscon bitfield to be used to control a multiplexer. The parent
I think "Define a register bitfield to be used ..." is more clear.
> +device tree node must be a syscon node to provide register access. > + > +Required properties: > +- compatible : "gpio-mux"
Er, "mmio-mux"
> +- reg : register base of the register containing the control bitfield > +- bit-mask : bitmask of the control bitfield in the control register > +- bit-shift : bit offset of the control bitfield in the control register > +- #mux-control-cells : <0> > +* Standard mux-controller bindings as decribed in mux-controller.txt > + > +Optional properties: > +- idle-state : if present, the state the mux will have when idle. The > + special state MUX_IDLE_AS_IS is the default. > + > +The multiplexer state is defined as the value of the bitfield described > +by the reg, bit-mask, and bit-shift properties, accessed through the parent > +syscon. > + > +Example: > + > + syscon { > + compatible = "syscon"; > + > + mux: mux-controller@3 { > + compatible = "mmio-mux"; > + reg = <0x3>; > + bit-mask = <0x1>; > + bit-shift = <5>; > + #mux-control-cells = <0>; > + }; > + }; > + > + video-mux {
I like this as an example consumer of a mmio-mux, but just the same some might argue this doesn't really fit here.
Steve
> + compatible = "video-mux"; > + mux-controls = <&mux>; > + > + ports { > + /* input 0 */ > + port@0 { > + reg = <0>; > + }; > + > + /* input 1 */ > + port@1 { > + reg = <1>; > + }; > + > + /* output */ > + port@2 { > + reg = <2>; > + }; > + }; > + };
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