[PATCH v2] dt-bindings: touchscreen: silead gsl1680: Document all compatibles

[Rob Herring]

On Thu, Aug 18, 2016 at 3:39 PM, Dmitry Torokhov
<dmitry.torokhov at gmail.com> wrote:
> On Thu, Aug 18, 2016 at 02:48:52PM -0500, Rob Herring wrote:
>> On Thu, Aug 18, 2016 at 2:30 PM, Dmitry Torokhov
>> <dmitry.torokhov at gmail.com> wrote:
>> > On Wed, Aug 17, 2016 at 10:59:00AM +0200, Hans de Goede wrote:
>> >> The silead gsl1680 driver / binding supports a whole series of devices,
>> >> list the compatibles for all of them in the binding.
>> >>
>> >> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
>> >> ---
>> >> Changes in v2:
>> >> -Drop the "silead,mssl1680" compatible thing, the "mssl1680" name is an
>> >>  ACPI thing and does not belong in the dt bindings
>> >> ---
>> >>  .../devicetree/bindings/input/touchscreen/silead_gsl1680.txt          | 4 ++++
>> >>  1 file changed, 4 insertions(+)
>> >>
>> >> diff --git a/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt b/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
>> >> index b0eca54..ad7f41a 100644
>> >> --- a/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
>> >> +++ b/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
>> >> @@ -2,6 +2,10 @@
>> >>
>> >>  Required properties:
>> >>  - compatible           : "silead,gsl1680"
>> >> +                     or: "silead,gsl1688"
>> >> +                     or: "silead,gsl3670"
>> >> +                     or: "silead,gsl3675"
>> >> +                     or: "silead,gsl3692"
>> >
>> > Hmm, why do we need to document all compatible strings? We usually have
>> > only least common denominator in drievr, and device tree uses form:
>> >
>> >         compatible = "silead,<exact model>", "silead,gsl1680";
>> >
>> > Rob?
>>
>> Because we require them in dts files even if the OS only uses the fallback.
>
> So how exactly should it be documented? I mean if there were more than 1
> OS they might have been using different fallbacks. How do we decide
> which entry should be "true" fallback?

It shouldn't matter which one an OS uses. There's typically only the
specific one and then a generic or 1st compatible chip one.

This is exactly why they need to be documented (and in a single place,
looking at you u-boot), so there is no confusion as to what
compatibles are allowed/valid for each platform.

Rob