On Wed 08 Nov 2023 at 11:04, Rob Herring <robh@xxxxxxxxxx> wrote:
> On Mon, Nov 06, 2023 at 11:32:48AM +0100, Jerome Brunet wrote:
>> s4 has been added to the compatible list while converting the Amlogic PWM
>> binding documentation from txt to yaml.
>>
>> However, on the s4, the clock bindings have different meaning compared to
>> previous SoCs.
>>
>> On previous SoCs the clock bindings used to describe which input the PWM
>> channel multiplexer should pick among its possible parents.
>>
>> This is very much tied to the driver implementation, instead of describing
>> the HW for what it is. When support for the Amlogic PWM was first added,
>> how to deal with clocks through DT was not as clear as it nowadays.
>> The Linux driver now ignores this DT setting, but still relies on the
>> hard-coded list of clock sources.
>>
>> On the s4, the input multiplexer is gone. The clock bindings actually
>> describe the clock as it exists, not a setting. The property has a
>> different meaning, even if it is still 2 clocks and it would pass the check
>> when support is actually added.
>>
>> Also the s4 cannot work if the clocks are not provided, so the property no
>> longer optional.
>>
>> Finally, for once it makes sense to see the input as being numbered
>> somehow. No need to bother with clock-names on the s4 type of PWM.
>>
>> Fixes: 43a1c4ff3977 ("dt-bindings: pwm: Convert Amlogic Meson PWM binding")
>> Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
>> ---
>> .../devicetree/bindings/pwm/pwm-amlogic.yaml | 68 ++++++++++++++++---
>> 1 file changed, 59 insertions(+), 9 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/pwm/pwm-amlogic.yaml b/Documentation/devicetree/bindings/pwm/pwm-amlogic.yaml
>> index 527864a4d855..754b70fc2db0 100644
>> --- a/Documentation/devicetree/bindings/pwm/pwm-amlogic.yaml
>> +++ b/Documentation/devicetree/bindings/pwm/pwm-amlogic.yaml
>> @@ -9,9 +9,6 @@ title: Amlogic PWM
>> maintainers:
>> - Heiner Kallweit <hkallweit1@xxxxxxxxx>
>>
>> -allOf:
>> - - $ref: pwm.yaml#
>> -
>> properties:
>> compatible:
>> oneOf:
>> @@ -43,12 +40,8 @@ properties:
>> maxItems: 2
>>
>> clock-names:
>> - oneOf:
>> - - items:
>> - - enum: [clkin0, clkin1]
>> - - items:
>> - - const: clkin0
>> - - const: clkin1
>> + minItems: 1
>> + maxItems: 2
>>
>> "#pwm-cells":
>> const: 3
>> @@ -57,6 +50,56 @@ required:
>> - compatible
>> - reg
>>
>> +allOf:
>> + - $ref: pwm.yaml#
>> +
>> + - if:
>> + properties:
>> + compatible:
>> + contains:
>> + enum:
>> + - amlogic,meson8-pwm
>> + - amlogic,meson8b-pwm
>> + - amlogic,meson-gxbb-pwm
>> + - amlogic,meson-gxbb-ao-pwm
>> + - amlogic,meson-axg-ee-pwm
>> + - amlogic,meson-axg-ao-pwm
>> + - amlogic,meson-g12a-ee-pwm
>> + - amlogic,meson-g12a-ao-pwm-ab
>> + - amlogic,meson-g12a-ao-pwm-cd
>> + - amlogic,meson-gx-pwm
>> + - amlogic,meson-gx-ao-pwm
>> + then:
>> + # Historic bindings tied to the driver implementation
>> + # The clocks provided here are meant to be matched with the input
>> + # known (hard-coded) in the driver and used to select pwm clock
>> + # source. Currently, the linux driver ignores this.
>> + properties:
>> + clock-names:
>> + oneOf:
>> + - items:
>> + - enum: [clkin0, clkin1]
>> + - items:
>> + - const: clkin0
>> + - const: clkin1
>> +
>> + # Newer IP block take a single input per channel, instead of 4 inputs
>> + # for both channels
>> + - if:
>> + properties:
>> + compatible:
>> + contains:
>> + enum:
>> + - amlogic,meson-s4-pwm
>> + then:
>> + properties:
>> + clocks:
>> + items:
>> + - description: input clock of PWM channel A
>> + - description: input clock of PWM channel B
>> + required:
>> + - clocks
>
> What are the 'clock-names' in this case? Because it's still allowed.
>
Indeed, it should not be.
I should add 'clock-names: false' , right ?
> Rob
