Thread (6 messages) 6 messages, 3 authors, 2015-07-16

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

From: Vaibhav Hiremath <hidden>
Date: 2015-07-16 14:16:13
Also in: linux-arm-kernel, linux-gpio, lkml


On Thursday 16 July 2015 06:28 PM, Linus Walleij wrote:
On Thu, Jul 2, 2015 at 6:53 PM, Vaibhav Hiremath
[off-list ref] wrote:
quoted
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.
Thanks for the reference, good to know this.
Let me check this driver before commenting anything further on this.

Thanks,
Vaibhav
Yours,
Linus Walleij
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