[RFC PATCH] pinctrl-single: Use of pinctrl-single for external device over I2C

[Linus Walleij]

On Thu, Jul 2, 2015 at 6:53 PM, Vaibhav Hiremath
<vaibhav.hiremath at linaro.org> wrote:

> In some usecases, the external device (in my case it PMIC over I2C)
> does support pin in multiple configuration, we may need to control/configure them
> during boot or runtime.

What is missing from this patch is an explanation why pinctrl-single should
be used for this PMIC.

Repeat: pinctrl-single: when you have exactly one register per pin, and
the description of the pins is delivered in an opaque ASIC-specific format
without developers knowing much about how the hardware actually works,
just "set these magic values".

I strongly prefer that this PMIC has its own pin controller using standard
bindings with groups and functions, see eg. drivers/pinctrl/nomadik/pinctrl-ab*
for a PMIC pinctrl driver.

Yours,
Linus Walleij