linux-kernel - Re: [PATCH v1 0/8] gpio: Get rid of ARCH_NR

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Date:   Tue, 30 Aug 2022 23:20:31 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Christophe Leroy <christophe.leroy@...roup.eu>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Keerthy <j-keerthy@...com>, Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        Jonathan Corbet <corbet@....net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        Linux-Arch <linux-arch@...r.kernel.org>,
        Linux Documentation List <linux-doc@...r.kernel.org>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>
Subject: Re: [PATCH v1 0/8] gpio: Get rid of ARCH_NR_GPIOS (v1)

On Mon, Aug 29, 2022 at 7:17 PM Christophe Leroy
<christophe.leroy@...roup.eu> wrote:
>
> Since commit 14e85c0e69d5 ("gpio: remove gpio_descs global array")
> there is no limitation on the number of GPIOs that can be allocated
> in the system since the allocation is fully dynamic.
>
> ARCH_NR_GPIOS is today only used in order to provide downwards
> gpiobase allocation from that value, while static allocation is
> performed upwards from 0. However that has the disadvantage of
> limiting the number of GPIOs that can be registered in the system.
>
> To overcome this limitation without requiring each and every
> platform to provide its 'best-guess' maximum number, rework the
> allocation to allocate from 256 upwards, allowing approx 2 millions
> of GPIOs.
>
> In the meantime, add a warning for drivers how are still doing
> static allocation, so that in the future the static allocation gets
> removed completely and dynamic allocation can start at base 0.

For non-commented (by me or others) patches
Reviewed-by: Andy Shevchenko <andy.shevchenko!gmail.com>
For the patch 1 if you are going to address as suggested by the author
of the driver, you may also add my tag.

> Christophe Leroy (8):
>   gpio: aggregator: Stop using ARCH_NR_GPIOS
>   gpio: davinci: Stop using ARCH_NR_GPIOS
>   gpiolib: Warn on drivers still using static gpiobase allocation
>   gpiolib: Get rid of ARCH_NR_GPIOS
>   Documentation: gpio: Remove text about ARCH_NR_GPIOS
>   x86: Remove CONFIG_ARCH_NR_GPIO
>   arm: Remove CONFIG_ARCH_NR_GPIO
>   arm64: Remove CONFIG_ARCH_NR_GPIO
>
>  Documentation/driver-api/gpio/legacy.rst |  5 ---
>  arch/arm/Kconfig                         | 21 ---------
>  arch/arm/include/asm/gpio.h              |  1 -
>  arch/arm64/Kconfig                       | 12 ------
>  arch/x86/Kconfig                         |  5 ---
>  drivers/gpio/gpio-aggregator.c           |  8 ++--
>  drivers/gpio/gpio-davinci.c              |  3 --
>  drivers/gpio/gpio-sta2x11.c              |  5 +--
>  drivers/gpio/gpiolib.c                   | 13 +++---
>  include/asm-generic/gpio.h               | 55 +++++++++---------------
>  10 files changed, 36 insertions(+), 92 deletions(-)
>
> --
> 2.37.1
>


-- 
With Best Regards,
Andy Shevchenko