On Mon 20 Nov 2023 at 10:55, neil.armstrong@xxxxxxxxxx wrote: > Hi Jerome, > > On 20/11/2023 10:18, Jerome Brunet wrote: >> On Mon 20 Nov 2023 at 09:27, Neil Armstrong <neil.armstrong@xxxxxxxxxx> >> wrote: >> >>> Hi Rob, >>> >>> On 19/11/2023 17:05, Rob Herring wrote: >>>> On Fri, 17 Nov 2023 13:59:12 +0100, Jerome Brunet wrote: >>>>> Add a new compatible for the pwm found in the meson8 to sm1 Amlogic SoCs. >>>>> >>>>> The previous clock bindings for these SoCs described the driver and not the >>>>> HW itself. The clock provided was used to set the parent of the input clock >>>>> mux among the possible parents hard-coded in the driver. >>>>> >>>>> The new bindings allows to describe the actual clock inputs of the PWM in >>>>> DT, like most bindings do, instead of relying of hard-coded data. >>>>> >>>>> The new bindings make the old one deprecated. >>>>> >>>>> There is enough experience on this HW to know that the PWM is exactly the >>>>> same all the supported SoCs. There is no need for a per-SoC compatible. >>>>> >>>>> Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx> >>>>> --- >>>>> .../devicetree/bindings/pwm/pwm-amlogic.yaml | 36 +++++++++++++++++-- >>>>> 1 file changed, 34 insertions(+), 2 deletions(-) >>>>> >>>> Reviewed-by: Rob Herring <robh@xxxxxxxxxx> >>>> >>> >>> I'm puzzled, isn't it recommended to have a per-soc compatible now ? >> I have specifically addressed this matter in the description, >> haven't I ? What good would it do in this case ? > > Yes you did but I was asked for the last year+ that all new compatible > should be soc specific (while imprecise, in our care soc family should be ok), > with a possible semi-generic callback with an IP version or a first soc > implementing the IP. > >> Plus the definition of a SoC is very vague. One could argue that >> the content of the list bellow are vaguely defined families. Should we >> add meson8b, gxl, gxm, sm1 ? ... or even the actual SoC reference ? >> This list gets huge for no reason. > > I think in our case soc family is reasonable since they share same silicon > design. > >> We know all existing PWM of this type are the same. We have been using >> them for years. It is not a new support we know nothing about. >> >>> >>> I thought something like: >>> - items: >>> - enum: >>> - amlogic,gxbb-pwm >>> - amlogic,axg-pwm >>> - amlogic,g12a-pwm >>> - const: amlogic,pwm-v1 >> I'm not sure I understand what you are suggesting here. >> Adding a "amlogic,pwm-v1" for the obsolete compatible ? No amlogic DT >> has that and I'm working to remove this type, so I don't get the point. >> >>> >>> should be preferred instead of a single amlogic,meson8-pwm-v2 ? >> This is named after the first SoC supporting the type. >> Naming it amlogic,pwm-v2 would feel weird with the s4 coming after. >> Plus the doc specifically advise against this type of names. > > The -v2 refers to a pure software/dt implementation versioning and not > an HW version, so I'm puzzled and I requires DT maintainers advice here. > > Yes meson8b is the first "known" platform, even if I'm pretty sure meson6 has This is not my point. I picked this name because I have to pick a specific device based one. Not because it is actually the first or not. I don't see a problem with meson6 being compatible with meson8-pwm-v2, if that ever comes along. I think the binding here satisfy the rule that it should be specific, and the intent that goes with it: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/writing-bindings.rst?h=v6.7-rc2#n42 > the same pwm architecture, this is why "amlogic,pwm-v1" as fallback seems more > reasonable and s4 and later pwm could use the "amlogic,pwm-v2" > fallback. That is not how understand this: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/writing-bindings.rst?h=v6.7-rc2#n82 > > Neil >> >>> >>> Neil >>
