Re: [PATCH 2/2] ARM: dts: MSM8974: Add pinctrl node

[Bjorn Andersson]

On Tue, Apr 8, 2014 at 7:18 AM, Timur Tabi <timur@xxxxxxxxxxxxxx> wrote:
> On 04/08/2014 08:46 AM, Ivan T. Ivanov wrote:
>>>
>>> >This patch adds that same exact information into the device tree.  Why
>>> >are we duplicating that information?  Why add it to the device tree when
>>> >it's already in the driver (and already working).
>
>
>> Probably. It was my natural way of thinking. Pin have a functions.
>> It is easier if I measure signals to just look at the device
>> tree file. What are you suggesting?
>
>
> Back in July, Qualcomm submitted a patch that added this information into
> the device tree:
>
> http://marc.info/?t=137185166100003&r=1&w=2
>
> However, this was rejected.  Now it appears that this information is again
> being added to the device tree, but it's being accepted.  What's different
> now?

The difference is that in the first proposal pins, groups and
functions where defined in DT, in the accepted proposal the devicetree
merely selects pins, functions and their configuration.

>
> Another problem is that these device tree changes makes it difficult to
> support ACPI.  It's easy to move information between the drivers and the
> device tree, because they're kept together.  It's not so easy with ACPI.
> I'm trying to add ACPI support to the 8x74 pinctrl driver, but it's a moving
> target.

The DT bindings for 8x74 is all standard pinctrl, so I presume that
what you should be looking at is how pinctrl and acpi is interacting,
not the specific case of 8x74...

Maybe Linus have some input on this?

Regards,
Bjorn
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