[PATCH] watchdog: meson-wdt: add support for the watchdog on Meson8 and Meson8m2

[Martin Blumenstingl]

Hi Rob,

On Sun, Jun 18, 2017 at 4:04 PM, Rob Herring <robh at kernel.org> wrote:
> On Thu, Jun 15, 2017 at 11:13:07PM +0200, Martin Blumenstingl wrote:
>> On Thu, Jun 15, 2017 at 7:25 PM, Guenter Roeck <linux at roeck-us.net> wrote:
>> > On Sun, Jun 11, 2017 at 11:52:19AM +0200, Martin Blumenstingl wrote:
>> >> The watchdog IP block on Meson8 and Meson8m2 is already supported by the
>> >> existing meson-wdt driver. Meson8 uses the same register bits as Meson6,
>> >> while the newer Meson8m2 SoC uses the same register bits as Meson8b.
>> >>
>> >> Currently watchdog support on Meson8 SoC already works because
>> >> meson8.dtsi simply uses the "amlogic,meson6-wdt" compatible. Adding a
>> >> separate compatible for Meson8 makes this more explicit though.
>> >>
>> >> Signed-off-by: Martin Blumenstingl <martin.blumenstingl at googlemail.com>
>> >
>> > Reviewed-by: Guenter Roeck <linux at roeck-us.net>
>> thank you!
>> is there anything holding you up from taking this patch (for example:
>> are you still missing any specific Signed-off-by / Acked-by)?
>>
>> > In general, changes like this are not necessary, though. The dts file
>> > is supposed to reference both generic and specific compatible strings.
>> I thought about skipping this patch, but I find that it looks strange without.
>>
>> the hierarchy and the corresponding compatible strings would be:
>> meson.dtsi / compatible = "amlogic,meson6-wdt";
>> |- meson8.dtsi / compatible = "amlogic,meson8-wdt", "amlogic,meson6-wdt";
>>    |- meson8m2.dtsi (upcoming) / compatible = "amlogic,meson8m2-wdt",
>> "amlogic,meson8b-wdt";
>> |- meson8b.dtsi / compatible = "amlogic,meson8b-wdt";
>>
>> instead of this seemingly random mixup of compatible strings I decided
>> to introduce separate ones for each SoC.
>
> But if the block is backwards compatible, you should also provide a
> fallback compatible string.
OK, fine with me - do you want me to update the documentation to
reflect this (or is it enough if I take care of it in the .dts files)?
the resulting documentation could look like this:
       "amlogic,meson6-wdt" on Meson6 SoCs
       "amlogic,meson8-wdt" along with "amlogic,meson6-wdt" on Meson8 SoCs
       "amlogic,meson8b-wdt" on Meson8b SoCs
       "amlogic,meson8m2-wdt" along with "amlogic,meson8b-wdt" on Meson8m2 SoCs

Regards,
Martin