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

From: Mathias Nyman
Date: Tue Apr 15 2014 - 05:50:26 EST


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
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