linux-kernel - Re: [PATCH 0/4] Fix Samsung pinctrl driver static allocation of GPIO base warning

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Date:   Fri, 6 Oct 2023 21:14:22 -0500
From:   Sam Protsenko <semen.protsenko@...aro.org>
To:     Mateusz Majewski <m.majewski2@...sung.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org, Tomasz Figa <tomasz.figa@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH 0/4] Fix Samsung pinctrl driver static allocation of GPIO
 base warning

On Fri, Oct 6, 2023 at 8:01 AM Mateusz Majewski <m.majewski2@...sung.com> wrote:
>
> The object of this work is fixing the following warning, which appears
> on all targets using that driver:
>
> gpio gpiochip0: Static allocation of GPIO base is deprecated, use dynamic allocation.
>
> This needs a small refactor to how we interact with the pinctrl
> subsystem. Finally, we remove some bookkeeping that has only been
> necessary to allocate GPIO bases correctly.
>
> Mateusz Majewski (4):
>   pinctrl: samsung: defer pinctrl_enable
>   pinctrl: samsung: use add_pin_ranges method to add pinctrl ranges
>   pinctrl: samsung: choose GPIO numberspace base dynamically
>   pinctrl: samsung: do not offset pinctrl numberspaces
>
>  drivers/pinctrl/samsung/pinctrl-samsung.c | 56 ++++++++++++-----------
>  drivers/pinctrl/samsung/pinctrl-samsung.h |  4 +-
>  2 files changed, 31 insertions(+), 29 deletions(-)
>
> --

Hi Mateusz,

Thank you for handling this! Those deprecation warnings have been
bugging me for some time :) While testing this series on my E850-96
board (Exynos850 based), I noticed some changes in
/sys/kernel/debug/gpio file, like these:

8<------------------------------------------------------------------------------------------>8
-gpiochip0: GPIOs 0-7, parent: platform/11850000.pinctrl, gpa0:
- gpio-7   (                    |Volume Up           ) in  hi IRQ ACTIVE LOW
+gpiochip0: GPIOs 512-519, parent: platform/11850000.pinctrl, gpa0:
+ gpio-519 (                    |Volume Up           ) in  hi IRQ ACTIVE LOW

-gpiochip1: GPIOs 8-15, parent: platform/11850000.pinctrl, gpa1:
- gpio-8   (                    |Volume Down         ) in  hi IRQ ACTIVE LOW
+gpiochip1: GPIOs 520-527, parent: platform/11850000.pinctrl, gpa1:
+ gpio-520 (                    |Volume Down         ) in  hi IRQ ACTIVE LOW

-gpiochip2: GPIOs 16-23, parent: platform/11850000.pinctrl, gpa2:
+gpiochip2: GPIOs 528-535, parent: platform/11850000.pinctrl, gpa2:

...
8<------------------------------------------------------------------------------------------>8

So basically it looks like all line numbers were offset by 512. Can
you please comment on this? Is it an intentional change, and why it's
happening?

Despite of that change, everything seems to be working fine. But I
kinda liked the numeration starting from 0 better :)

Thanks!

> 2.42.0
>