Re: [alsa-devel] [RESEND PATCH v4 1/4] dt-bindings: soundwire: add slave bindings

[Srinivas Kandagatla]

On 23/08/2019 16:41, Pierre-Louis Bossart wrote:
> On 8/22/19 6:37 PM, Srinivas Kandagatla wrote:
> > This patch adds bindings for Soundwire Slave devices that includes how
> > SoundWire enumeration address and Link ID are used to represented in
> > SoundWire slave device tree nodes.
> >
> > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > ---
> > Â .../soundwire/soundwire-controller.yamlÂÂÂÂÂÂ | 75 +++++++++++++++++++
> > Â 1 file changed, 75 insertions(+)
> > Â create mode 100644 
> > Documentation/devicetree/bindings/soundwire/soundwire-controller.yaml
> >
> > diff --git 
> > a/Documentation/devicetree/bindings/soundwire/soundwire-controller.yaml b/Documentation/devicetree/bindings/soundwire/soundwire-controller.yaml 
> >
> > new file mode 100644
> > index 000000000000..91aa6c6d6266
> > --- /dev/null
> > +++ 
> > b/Documentation/devicetree/bindings/soundwire/soundwire-controller.yaml
> > @@ -0,0 +1,75 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/soundwire/soundwire-controller.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: SoundWire Controller Generic Binding
> > +
> > +maintainers:
> > +Â - Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > +
> > +description: |
> > +Â SoundWire busses can be described with a node for the SoundWire 
> > controller
> > +Â device and a set of child nodes for each SoundWire slave on the bus.
> > +
> > +properties:
> > +Â $nodename:
> > +ÂÂÂ pattern: "^soundwire(@.*|-[0-9a-f])*$"
> > +
> > +Â "#address-cells":
> > +ÂÂÂ const: 2
> > +
> > +Â "#size-cells":
> > +ÂÂÂ const: 0
> > +
> > +patternProperties:
> > +Â "^.*@[0-9a-f]+$":
> > +ÂÂÂ type: object
> > +
> > +ÂÂÂ properties:
> > +ÂÂÂÂÂ compatible:
> > +ÂÂÂÂÂ pattern: "^sdw[0-9][0-9a-f]{4}[0-9a-f]{4}[0-9a-f]{2}$"
>
> So is this a 64-bit value, as in the MIPI spec, or is this part of the 
> _ADR description?

Rob did not like encoding compatible string exactly like _ADR encoding.

https://lkml.org/lkml/2019/8/22/490

> I also don't get why the first item in in base10?

As this corresponds to Soundwire Version, and I have no visibility of 
version number encoding after reaching number 9 in this field.

This can be updated once we have more info on how the Version encoding 
will look like in future.

Idea of limiting regex to [0-9] for version is to enforce some checking!

--srini

> > +ÂÂÂÂÂ description:
> > +ÂÂÂÂÂ Is the textual representation of SoundWire Enumeration
> > +ÂÂÂÂÂ address. compatible string should contain SoundWire Version ID,
> > +ÂÂÂÂÂ Manufacturer ID, Part ID and Class ID in order and shall be in
> > +ÂÂÂÂÂ lower-case hexadecimal with leading zeroes.
> > +ÂÂÂÂÂ Valid sizes of these fields are
> > +ÂÂÂÂÂ Version ID is 1 nibble, number '0x1' represents SoundWire 1.0
> > +ÂÂÂÂÂ and '0x2' represents SoundWire 1.1 and so on.
> > +ÂÂÂÂÂ MFD is 4 nibbles
> > +ÂÂÂÂÂ PID is 4 nibbles
> > +ÂÂÂÂÂ CID is 2 nibbles
> > +ÂÂÂÂÂ More Information on detail of encoding of these fields can be
> > +ÂÂÂÂÂ found in MIPI Alliance DisCo & SoundWire 1.0 Specifications.
> > +
> > +ÂÂÂÂÂ reg:
> > +ÂÂÂÂÂÂÂ maxItems: 1
> > +ÂÂÂÂÂÂÂ description:
> > +ÂÂÂÂÂÂÂÂÂ Instance ID and Link ID of SoundWire Device Address.
> > +
> > +ÂÂÂ required:
> > +ÂÂÂÂÂ - compatible
> > +ÂÂÂÂÂ - reg
> > +
> > +examples:
> > +Â - |
> > +ÂÂÂ soundwire@c2d0000 {
> > +ÂÂÂÂÂÂÂ #address-cells = <2>;
> > +ÂÂÂÂÂÂÂ #size-cells = <0>;
> > +ÂÂÂÂÂÂÂ compatible = "qcom,soundwire-v1.5.0";
> > +ÂÂÂÂÂÂÂ reg = <0x0c2d0000 0x2000>;
> > +
> > +ÂÂÂÂÂÂÂ speaker@1 {
> > +ÂÂÂÂÂÂÂÂÂÂÂ compatible = "sdw10217201000";
> > +ÂÂÂÂÂÂÂÂÂÂÂ reg = <1 0>;
> > +ÂÂÂÂÂÂÂ };
> > +
> > +ÂÂÂÂÂÂÂ speaker@2 {
> > +ÂÂÂÂÂÂÂÂÂÂÂ compatible = "sdw10217201000";
> > +ÂÂÂÂÂÂÂÂÂÂÂ reg = <2 0>;
> > +ÂÂÂÂÂÂÂ };
> > +ÂÂÂ };
> > +
> > +...