Re: [PATCH 1/2] dt-bindings: clock: document the fsl-sai driver

[Michael Walle <michael@walle.cc>]

Am 2019-12-05 16:16, schrieb Rob Herring:
> On Sat, Nov 23, 2019 at 12:56:21AM +0100, Michael Walle wrote:
>> Signed-off-by: Michael Walle <michael@walle.cc>
>> ---
>>  .../bindings/clock/fsl,sai-clock.yaml         | 48 
>> +++++++++++++++++++
>>  1 file changed, 48 insertions(+)
>>  create mode 100644 
>> Documentation/devicetree/bindings/clock/fsl,sai-clock.yaml
>> 
>> diff --git 
>> a/Documentation/devicetree/bindings/clock/fsl,sai-clock.yaml 
>> b/Documentation/devicetree/bindings/clock/fsl,sai-clock.yaml
>> new file mode 100644
>> index 000000000000..7116c8bc24d3
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/clock/fsl,sai-clock.yaml
>> @@ -0,0 +1,48 @@
>> +# SPDX-License-Identifier: GPL-2.0
> 
> Dual license new bindings please: (GPL-2.0-only OR BSD-2-Clause)

sure.

> 
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/bindings/clock/fsl,sai-clock.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Freescale SAI bitclock-as-a-clock binding
>> +
>> +maintainers:
>> +  - Michael Walle <michael@walle.cc>
>> +
>> +description: |
>> +  It is possible to use the BCLK pin of a SAI module as a generic 
>> clock
>> +  output. Some SoC are very constrained in their pin multiplexer
>> +  configuration. Eg. pins can only be changed groups. For example, on 
>> the
>> +  LS1028A SoC you can only enable SAIs in pairs. If you use only one 
>> SAI,
>> +  the second pins are wasted. Using this binding it is possible to 
>> use the
>> +  clock of the second SAI as a MCLK clock for an audio codec, for 
>> example.
>> +
>> +  This is a composite of a gated clock and a divider clock.
>> +
>> +properties:
>> +  compatible:
>> +    const: fsl,vf610-sai-clock
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  clocks:
>> +    maxItems: 1
>> +
>> +  '#clock-cells':
>> +    const: 0
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - clocks
>> +  - '#clock-cells'
>> +
> 
> Add:
> 
> additionalProperties: false

ok.

>> +examples:
>> +  - |
>> +    mclk: clock-mclk@f130080 {
>> +        compatible = "fsl,vf610-sai-clock";
>> +        reg = <0x0 0xf130080 0x0 0x80>;
> 
> Examples are built now and this will fail because the default
> #address-cells and #size-cells are 1.

Mh, I've run the make dt_binding_check on this. It wasn't flagged,
but I guess thats because its interpreted as two resources.

I haven't found anything how you can change the default. Or do you
mean I should change the example to just use one address cell and
one size cell? But then how would that work for examples (on other
bindings) where there should be size-cells = <0> for example.

> 
>> +        #clock-cells = <0>;
>> +        clocks = <&parentclk>;
>> +    };
>> --
>> 2.20.1
>>