Re: [PATCH v2 1/6] dt-bindings: Remove unused compatible strings

Paul Cercueil
2019-07-09T03:18:38Z

Le lun. 8 juil. 2019 à 22:04, Rob Herring <robh@kernel.org> a écrit :
> On Fri, Jun 07, 2019 at 05:44:05PM +0200, Paul Cercueil wrote:
>> Right now none of the Ingenic-based boards probe this driver from
>> devicetree. This driver defined three compatible strings for the
>> exact
>> same behaviour. Before these strings are used, we can remove two of
>> them.
>>
>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>> ---
>>
>> Notes:
>> v2: Rebase on v5.2-rc3
>>
>> Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt | 5
>> +----
>> 1 file changed, 1 insertion(+), 4 deletions(-)
>>
>> diff --git
>> a/Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt
>> b/Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt
>> index 7d9d3f90641b..493bec80d59b 100644
>> --- a/Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt
>> +++ b/Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt
>> @@ -2,10 +2,7 @@ Ingenic JZ47xx PWM Controller
>> =============================
>>
>> Required properties:
>> -- compatible: One of:
>> - * "ingenic,jz4740-pwm"
>> - * "ingenic,jz4770-pwm"
>> - * "ingenic,jz4780-pwm"
>> +- compatible: Should be "ingenic,jz4740-pwm"
>
> Are you sure all 3 chips are exactly the same features and bugs?

The hardware on these chips have tiny differences, but the current
driver code works on all the SoCs.

> The correct thing to do here generally is the 4770 and 4780 would also
> have ingenic,jz4740-pwm as a fallback compatible. Then the driver can
> match on that until you find some difference and can use the more
> specific compatible.

Why not just update the devicetree with the new compatible string when
a difference is found?

>> - #pwm-cells: Should be 3. See pwm.txt in this directory for a
>> description
>> of the cells format.
>> - clocks : phandle to the external clock.
>> --
>> 2.21.0.593.g511ec345e18
>>