Re: [PATCH v3 1/1] pinctrl: add Intel BayTrail GPIO/pinctrl support

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 04/14/2014 06:11 PM, Timur Tabi wrote:
> On 04/14/2014 02:52 AM, Mathias Nyman wrote:
>>>
>>
>> This was the conclusion we reached after some discussion with Linus W.
>> Initially this was just a GPIO driver, but Linus correctly spotted that
>> Baytrail has many pinctrl-like features (like pin muxing, etc) that we
>> might need to address in the future.
>>
>> threads where this was discussed:
>>
>> http://marc.info/?l=linux-kernel&m=136994203308585&w=2
>> http://marc.info/?l=linux-kernel&m=137113578604763&w=2
>
> So this is the interesting part:
>
>> We expect BIOS to set all pin configurations correctly.
>
> This device will only be used on an ACPI system, right?  And isn't ACPI
> supposed to hide all the pinctrl programming from the OS?  I thought
> that was the whole point behind ACPI and the reason why ARM64 isn't
> going to use device trees.
>

This was my starting point as well, and the driver was initially 
submitted as a GPIO driver. But Linus W. suggested pinctrl instead, and 
as he's the maintainer of both those subsystem I trust his judgment.


-Mathias