Hi Rob, On Wed, 2020-01-15 at 12:45 -0600, Rob Herring wrote: > On Tue, Jan 14, 2020 at 5:39 PM Chris Packham > <chris.packham@xxxxxxxxxxxxxxxxxxx> wrote: > > > > Add binding documentation for the spi-mux driver. This allows a > > generic > > multiplexer to be used to provide access to multiple SPI devices. > > > > Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx> > > --- > > .../devicetree/bindings/spi/spi-mux.yaml | 82 > > +++++++++++++++++++ > > 1 file changed, 82 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/spi/spi- > > mux.yaml > > Be sure to run 'make dt_binding_check'. > Will do. > > > > diff --git a/Documentation/devicetree/bindings/spi/spi-mux.yaml > > b/Documentation/devicetree/bindings/spi/spi-mux.yaml > > new file mode 100644 > > index 000000000000..1026d03a69c7 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/spi/spi-mux.yaml > > @@ -0,0 +1,82 @@ > > +# SPDX-License-Identifier: GPL-2.0 > > Dual license new bindings please: > > (GPL-2.0-only OR BSD-2-Clause) > Done > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/spi/spi-mux.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: Generic SPI Multiplexer > > + > > +description: | > > + This binding describes a SPI bus multiplexer to route the SPI > > chip select > > + signals. This can be used when you need more devices than the > > SPI controller > > + has chip selects available. An example setup is shown in ASCII > > art; the actual > > + setting of the multiplexer to a channel needs to be done by a > > specific SPI mux > > + driver. > > + > > + MOSI /--------------------------------+--------+--------+- > > -------\ > > + MISO |/------------------------------+|-------+|-------+|- > > ------\| > > + SCL ||/----------------------------+||------+||------+||- > > -----\|| > > + ||| ||| ||| ||| > > ||| > > + +---------- > > --+ ||| ||| ||| ||| > > + | SoC ||| | +-+++-+ +-+++-+ +-+++- > > + +-+++-+ > > + | ||| | | dev | | dev | | dev > > | | dev | > > + | +--+++-+ | CS-X +------+\ +--+--+ +--+--+ +--+ > > --+ +--+--+ > > + | | SPI +-|-------+ Mux |\\ CS-0 > > | | | | > > + | +------+ | +--+---+\\\-------/ CS-1 > > | | | > > + | | | \\\----------------/ CS-2 > > | | > > + | +------+ | | \\------------------------- > > / CS-3 | > > + | | ? +-|----------/ \-------------------------- > > --------/ > > + | +------+ | > > + +------------+ > > + > > +allOf: > > + - $ref: "/schemas/spi/spi-controller.yaml#" > > + > > +properties: > > + compatible: > > + const: spi-mux > > + > > + mux-control: > > + $ref: "/schemas/mux/mux-controller.yaml#" > > That file doesn't exist. If it did, it would still be wrong as that > would be the provider side and this is the client. > > The correct name is also 'mux-controls'. > > You can assume it has a schema already and you just need to define > how > many entries it has (maxItems: 1). I might need a little hand holding on this. Should I assume that there is a separate schema for the consumer? Or leave out the $ref entirely? > > + > > +required: > > + - compatible > > + - reg > > + - spi-max-frequency > > + - mux-control > > + > > +examples: > > + - | > > + mux: mux-controller { > > + compatible = "gpio-mux"; > > + #mux-control-cells = <0>; > > + > > + mux-gpios = <&gpio0 3 GPIO_ACTIVE_HIGH>; > > + }; > > + > > + spi { > > + spi-mux { > > spi-mux@0 > Done. > > + compatible = "spi-mux"; > > + #address-cells = <1>; > > + #size-cells = <0>; > > + reg = <0>; > > + spi-max-frequency = <100000000>; > > I don't think this makes sense here. The mux doesn't really have any > frequency given the clock and data lines aren't routed thru the mux > (though maybe that's possible if some isolation is needed). > It's needed to satisfy of_spi_parse_dt().To remove it I'd need to add an escape hatch to allow this property to be omitted for spi-muxes. Or change it to be a platform device and take the parent spi bus as a phandle. > > + > > + mux-control = <&mux> > > + mux-control-names = "spi"; > > Not documented. Drop it as it's not all that useful when there's only > 1 entry. Done. Also updated mux-control -> mux-controls > > + > > + spi-flash@0 { > > + compatible = "jedec,spi-nor"; > > + #address-cells = <1>; > > + #size-cells = <1>; > > + reg = <0>; > > + spi-max-frequency = <40000000>; > > + }; > > + > > + spi-device@1 { > > + compatible = "spidev"; > > Not a valid compatible. > Picked a different one. > > + reg = <1>; > > + spi-max-frequency = <10000000>; > > + }; > > + }; > > + }; > > -- > > 2.25.0 > >
