Re: [PATCH v6 4/6] gpio: davinci: add OF support

[Prabhakar Lad]

Hi Sekhar,

Thanks for the review.

On Mon, Nov 25, 2013 at 4:30 PM, Sekhar Nori <nsekhar@xxxxxx> wrote:
> On Thursday 21 November 2013 11:45 PM, Prabhakar Lad wrote:
>> From: KV Sujith <sujithkv@xxxxxx>
>>
>> This patch adds OF parser support for davinci gpio
>> driver and also appropriate documentation in gpio-davinci.txt
>> located at Documentation/devicetree/bindings/gpio/.
>>
>> Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
>> Acked-by: Rob Herring <rob.herring@xxxxxxxxxxx>
>> Signed-off-by: KV Sujith <sujithkv@xxxxxx>
>> Signed-off-by: Philip Avinash <avinashphilip@xxxxxx>
>> [prabhakar.csengg@xxxxxxxxx: simplified the OF code, removed
>>               unnecessary DT property and also simplified
>>               the commit message]
>> Signed-off-by: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx>
>> ---
>>  .../devicetree/bindings/gpio/gpio-davinci.txt      |   41 ++++++++++++++
>>  drivers/gpio/gpio-davinci.c                        |   57 ++++++++++++++++++--
>>  2 files changed, 95 insertions(+), 3 deletions(-)
>>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-davinci.txt
>>
>> diff --git a/Documentation/devicetree/bindings/gpio/gpio-davinci.txt b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt
>> new file mode 100644
>> index 0000000..a2e839d
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/gpio/gpio-davinci.txt
>> @@ -0,0 +1,41 @@
>> +Davinci GPIO controller bindings
>> +
>> +Required Properties:
>> +- compatible: should be "ti,dm6441-gpio"
>> +
>> +- reg: Physical base address of the controller and the size of memory mapped
>> +       registers.
>> +
>> +- gpio-controller : Marks the device node as a gpio controller.
>> +
>> +- interrupt-parent: phandle of the parent interrupt controller.
>> +
>> +- interrupts: Array of GPIO interrupt number. Only banked or unbanked IRQs are
>> +           supported at a time.
>
> If this is true..
>
>> +
>> +- ti,ngpio: The number of GPIO pins supported.
>> +
>> +- ti,davinci-gpio-unbanked: The number of GPIOs that have an individual interrupt
>> +                          line to processor.
>
> .. then why do you need to maintain this separately? Number of elements
> in interrupts property should give you this answer, no?
>
> There can certainly be devices (past and future) which use a mixture of
> banked and unbanked IRQs. So a binding which does not take care of this
> is likely to change in future and that is a problem since it brings in
> backward compatibility of the binding into picture.
>
> The right thing would be to define the DT node per-bank similar to what
> is done on OMAP rather than for all banks together. That way there can
> be a separate property which determines whether that bank supports
> direct-mapped or banked IRQs (or that could be inferred if the number of
> tuples in the interrupts property is more than one).
>
Can you point me to the OMAP implementation.

Regards,
--Prabhakar Lad
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