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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Tue, 14 Sep 2021 15:02:07 +0200
Message-ID: <CAK8P3a3ZBfTN-u1xtQx3TTFnangdyXc7B8wMtr51Mr6+aXvodA@mail.gmail.com>
Subject: Re: [RFC PATCH V4 6/6] riscv: soc: Add Allwinner SoC kconfig option
To:     Krzysztof Kozlowski <krzk@kernel.org>
Cc:     Maxime Ripard <maxime@cerno.tech>, Arnd Bergmann <arnd@arndb.de>,
        Guo Ren <guoren@kernel.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Anup Patel <anup.patel@wdc.com>,
        Atish Patra <atish.patra@wdc.com>,
        Palmer Dabbelt <palmerdabbelt@google.com>,
        =?UTF-8?Q?Christoph_M=C3=BCllner?= <christoph.muellner@vrull.eu>,
        philipp.tomsich@vrull.eu, Christoph Hellwig <hch@lst.de>,
        liush <liush@allwinnertech.com>, wefu@redhat.com,
        =?UTF-8?B?V2VpIFd1ICjlkLTkvJ8p?= <lazyparser@gmail.com>,
        Drew Fustini <drew@beagleboard.org>,
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On Tue, Sep 14, 2021 at 2:11 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On 14/09/2021 12:13, Maxime Ripard wrote:
> > On Tue, Sep 14, 2021 at 12:07:08PM +0200, Krzysztof Kozlowski wrote:
> >> On Tue, 14 Sept 2021 at 11:31, Arnd Bergmann <arnd@arndb.de> wrote:
> >>> Some subsystem maintainers want drivers to be selected by the SoC
> >>> option, this is why you need the 'select SIFIVE_PLIC', but usually
> >>> the drivers are selectable with a 'depends on ARCH_SUNXI ||
> >>> COMPILE_TEST' and enabled in the defconfig.
> >>
> >> I would say selecting drivers is even more useful for distros and
> >> other downstream users. Especially in the ARM world where we have so
> >> many different SoCs - how could a distro person know which driver is
> >> necessary, important or useful? Having all main SoC drivers enabled
> >> when ARCH_SUNXI=y, helps distro a lot.
> >
> > Imply, maybe, but select is far too painful for everyone else.
>
> If we talk about UART driver, then sure - imply makes sense. But if we
> talk about core SoC components necessary for boot (e.g. timers, clocks,
> pinctrl), then select is appropriate. There is no point to enable
> ARCH_XXX without these core components.

Please never use 'imply', this is functionally the same as 'default', just
the wrong way around, like the infamous 'comefrom' instruction
in programming languages ;-)

I still prefer using defaults and defconfig files over 'select', but I can
see the use of select in some cases, as long as the symbol you
are selecting is not already user visible.

        Arnd