Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <cover.1661789204.git.christophe.leroy@csgroup.eu>
In-Reply-To: <cover.1661789204.git.christophe.leroy@csgroup.eu>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Tue, 30 Aug 2022 23:20:31 +0300
Message-ID: <CAHp75Vc5um3=gwnjoJNPxp+kbhFHT0Kp4gi1Qd+q5TL-y6-+oQ@mail.gmail.com>
Subject: Re: [PATCH v1 0/8] gpio: Get rid of ARCH_NR_GPIOS (v1)
To:     Christophe Leroy <christophe.leroy@csgroup.eu>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <brgl@bgdev.pl>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Keerthy <j-keerthy@ti.com>, Russell King <linux@armlinux.org.uk>,
        Arnd Bergmann <arnd@arndb.de>,
        Jonathan Corbet <corbet@lwn.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        Linux-Arch <linux-arch@vger.kernel.org>,
        Linux Documentation List <linux-doc@vger.kernel.org>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Mon, Aug 29, 2022 at 7:17 PM Christophe Leroy
<christophe.leroy@csgroup.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