Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document

From: Jon Hunter
Date: Fri Mar 18 2016 - 04:37:35 EST



On 17/03/16 20:14, Rob Herring wrote:
> On Thu, Mar 17, 2016 at 9:19 AM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
>> Commit afbbd2338176 ("irqchip/gic: Document optional Clock and Power
>> Domain properties") documented optional clock and power-dmoain properties
>> for the ARM GIC. Currently, there are no users of these and for the
>> Tegra210 Audio GIC (based upon the GIC-400) there are two clocks, a
>> functional clock and interface clock, that need to be enabled.
>>
>> To allow flexibility, drop the 'clock-names' from the GIC binding and
>> just provide a list of clocks which the driver can parse. It is assumed
>> that any clocks that are listed, need to be enabled in order to access
>> the GIC.
>>
>> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
>>
>> ---
>>
>> Please note that I am not sure if this will be popular, but I am trying
>> to come up with a generic way to handle multiple clocks that may be
>> required for accessing a GIC.
>
> It's not. :)
>
> We need to specify the number and order of clocks by compatible string
> at a minimum. Sadly, ARM's GICs are well documented and include clock
> names, so you can't just make up genericish names either which is
> probably often the case.

Do you have any suggestions then?

I have had a look at the ARM TRMs and although I see that they do show
the functional clock, there is no mention of whether there are any other
clocks need in order to interface to the GIC (ie. bus clock). I know
that for other SoCs such as OMAP it is common to have both a functional
clock and interface clock. So I believe this is fairly common.

Cheers
Jon