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

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

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@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@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?

> 
> >
> > BTW, I do not see OF match table in the driver, did I manage to drop it?
> 
> If it is i2c, i2c has the quirk that it will match drv name to
> compatible string with vendor prefix dropped.

I think this is implementation quirk of I2C bus and I hope we'll fix it
one of these days... Same with modalias dropping vendor prefix so we
have to repeat OF data (sans vendor prefix) in I2C ID table if we want
module auto-loading to work.

> But that would imply one
> of these is a fallback and the doc doesn't say that.

Thanks.

-- 
Dmitry