linux-kernel - Re: [PATCH 5/7] ARM: samsung: Kill useless HAVE_S3C2410

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Date:   Wed, 29 Jul 2020 19:36:38 +0200
From:   Tomasz Figa <tomasz.figa@...il.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Krzysztof Kozlowski <krzk@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Kukjin Kim <kgene@...nel.org>,
        Vincent Sanders <vince@...tec.co.uk>,
        Simtec Linux Team <linux@...tec.co.uk>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Arnd Bergmann <arnd@...db.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:SAMSUNG SOC CLOCK DRIVERS" 
        <linux-samsung-soc@...r.kernel.org>,
        linux-stm32@...md-mailman.stormreply.com,
        patches@...nsource.cirrus.com,
        "open list:COMMON CLK FRAMEWORK" <linux-clk@...r.kernel.org>,
        linux-watchdog@...r.kernel.org,
        Sergio Prado <sergio.prado@...abworks.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Sylwester Nawrocki <snawrocki@...nel.org>,
        Cedric Roux <sed@...e.fr>, Lihua Yao <ylhuajnu@...look.com>
Subject: Re: [PATCH 5/7] ARM: samsung: Kill useless HAVE_S3C2410_WATCHDOG

2020年7月29日(水) 19:02 Guenter Roeck <linux@...ck-us.net>:
>
> On Wed, Jul 29, 2020 at 06:09:40PM +0200, Krzysztof Kozlowski wrote:
> > A separate Kconfig option HAVE_S3C2410_WATCHDOG for Samsung SoCs does
> > not have sense, because:
> > 1. All ARMv7 and ARMv8 Samsung SoCs have watchdog,
> > 2. All architecture Kconfigs were selecting it (if WATCHDOG framework is
> >    chosen),
> > 3. HAVE_S3C2410_WATCHDOG is doing nothing except being a dependency of
> >    actual Samsung SoC watchdog driver, which is enabled manually by
> >    specific defconfigs.
> >
> > HAVE_S3C2410_WATCHDOG can be safely removed.
> >
>
> That is not really correct. HAVE_S3C2410_WATCHDOG is used to ensure
> that users can only enable S3C2410_WATCHDOG if the watchdog actually
> exists in a system. With this change, it can be enabled for all
> architectures and platforms.
>
> NACK.
>
> Guenter
>

I'd side with Guenter on this. We better not flood users' screens with
options that are not relevant to their hardware.

An alternative here could be making CONFIG_S3C2410_WATCHDOG depend on
a general symbol for Samsung SoC support if there is such, but then,
are we 100% sure that all the Samsung SoCs would actually have exactly
this watchdog? If a new one shows up, one would have to bring back
this HAVE_S3C2410_WATCHDOG symbol.

Best regards,
Tomasz

> > Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> > ---
> >  arch/arm/Kconfig              | 1 -
> >  arch/arm/mach-exynos/Kconfig  | 1 -
> >  arch/arm/mach-s3c64xx/Kconfig | 2 --
> >  arch/arm/mach-s5pv210/Kconfig | 1 -
> >  arch/arm64/Kconfig.platforms  | 1 -
> >  drivers/watchdog/Kconfig      | 8 --------
> >  6 files changed, 14 deletions(-)
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 7564f293f107..fe95777af653 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -504,7 +504,6 @@ config ARCH_S3C24XX
> >       select GPIOLIB
> >       select GENERIC_IRQ_MULTI_HANDLER
> >       select HAVE_S3C2410_I2C if I2C
> > -     select HAVE_S3C2410_WATCHDOG if WATCHDOG
> >       select HAVE_S3C_RTC if RTC_CLASS
> >       select NEED_MACH_IO_H
> >       select SAMSUNG_ATAGS
> > diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
> > index f185cd3d4c62..d2d249706ebb 100644
> > --- a/arch/arm/mach-exynos/Kconfig
> > +++ b/arch/arm/mach-exynos/Kconfig
> > @@ -24,7 +24,6 @@ menuconfig ARCH_EXYNOS
> >       select HAVE_ARM_ARCH_TIMER if ARCH_EXYNOS5
> >       select HAVE_ARM_SCU if SMP
> >       select HAVE_S3C2410_I2C if I2C
> > -     select HAVE_S3C2410_WATCHDOG if WATCHDOG
> >       select HAVE_S3C_RTC if RTC_CLASS
> >       select PINCTRL
> >       select PINCTRL_EXYNOS
> > diff --git a/arch/arm/mach-s3c64xx/Kconfig b/arch/arm/mach-s3c64xx/Kconfig
> > index ac3e3563487f..e208c2b48853 100644
> > --- a/arch/arm/mach-s3c64xx/Kconfig
> > +++ b/arch/arm/mach-s3c64xx/Kconfig
> > @@ -13,7 +13,6 @@ menuconfig ARCH_S3C64XX
> >       select GPIO_SAMSUNG if ATAGS
> >       select GPIOLIB
> >       select HAVE_S3C2410_I2C if I2C
> > -     select HAVE_S3C2410_WATCHDOG if WATCHDOG
> >       select HAVE_TCM
> >       select PLAT_SAMSUNG
> >       select PM_GENERIC_DOMAINS if PM
> > @@ -165,7 +164,6 @@ config MACH_SMDK6410
> >       bool "SMDK6410"
> >       depends on ATAGS
> >       select CPU_S3C6410
> > -     select HAVE_S3C2410_WATCHDOG if WATCHDOG
> >       select S3C64XX_SETUP_FB_24BPP
> >       select S3C64XX_SETUP_I2C1
> >       select S3C64XX_SETUP_IDE
> > diff --git a/arch/arm/mach-s5pv210/Kconfig b/arch/arm/mach-s5pv210/Kconfig
> > index 03984a791879..b3db1191e437 100644
> > --- a/arch/arm/mach-s5pv210/Kconfig
> > +++ b/arch/arm/mach-s5pv210/Kconfig
> > @@ -14,7 +14,6 @@ config ARCH_S5PV210
> >       select COMMON_CLK_SAMSUNG
> >       select GPIOLIB
> >       select HAVE_S3C2410_I2C if I2C
> > -     select HAVE_S3C2410_WATCHDOG if WATCHDOG
> >       select HAVE_S3C_RTC if RTC_CLASS
> >       select PINCTRL
> >       select PINCTRL_EXYNOS
> > diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms
> > index cd58f8495c45..d235b27cf372 100644
> > --- a/arch/arm64/Kconfig.platforms
> > +++ b/arch/arm64/Kconfig.platforms
> > @@ -80,7 +80,6 @@ config ARCH_EXYNOS
> >       select EXYNOS_CHIPID
> >       select EXYNOS_PM_DOMAINS if PM_GENERIC_DOMAINS
> >       select EXYNOS_PMU
> > -     select HAVE_S3C2410_WATCHDOG if WATCHDOG
> >       select HAVE_S3C_RTC if RTC_CLASS
> >       select PINCTRL
> >       select PINCTRL_EXYNOS
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index 4f4687c46d38..ae86ea135d2b 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -478,16 +478,8 @@ config IXP4XX_WATCHDOG
> >
> >         Say N if you are unsure.
> >
> > -config HAVE_S3C2410_WATCHDOG
> > -     bool
> > -     help
> > -       This will include watchdog timer support for Samsung SoCs. If
> > -       you want to include watchdog support for any machine, kindly
> > -       select this in the respective mach-XXXX/Kconfig file.
> > -
> >  config S3C2410_WATCHDOG
> >       tristate "S3C2410 Watchdog"
> > -     depends on HAVE_S3C2410_WATCHDOG || COMPILE_TEST
> >       select WATCHDOG_CORE
> >       select MFD_SYSCON if ARCH_EXYNOS
> >       help
> > --
> > 2.17.1
> >