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From:   Orson Zhai <orsonzhai@gmail.com>
Date:   Mon, 9 Mar 2020 22:10:41 +0800
Message-ID: <CA+H2tpFBDSGfwYT--G_FsaEceNJW_xBJjjiSMnhZDVhZamj_QQ@mail.gmail.com>
Subject: Re: [PATCH 2/2] tty: serial: make SERIAL_SPRD not depend on ARCH_SPRD
To:     Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     Chunyan Zhang <zhang.lyra@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, Jiri Slaby <jslaby@suse.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Chunyan Zhang <chunyan.zhang@unisoc.com>,
        "open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
        Baolin Wang <baolin.wang7@gmail.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        kernel-team@android.com
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Hi Geert,


On Mon, Mar 9, 2020 at 4:01 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Chunyan,
>
> On Mon, Mar 9, 2020 at 2:18 AM Chunyan Zhang <zhang.lyra@gmail.com> wrote:
> > On Fri, 6 Mar 2020 at 20:41, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > On Thu, Mar 5, 2020 at 11:33 AM Chunyan Zhang <zhang.lyra@gmail.com> wrote:
> > > > From: Chunyan Zhang <chunyan.zhang@unisoc.com>
> > > >
> > > > Remove the dependency with ARCH_SPRD from sprd serial/console Kconfig-s,
> > > > since we want them can be built-in when ARCH_SPRD is set as 'm'.
> > >
> > > Why would you want a serial driver for a specific platform to be builtin,
> > > while all other platform support is modular?
> >
> > Oh, that's not this patch means.
> >
> > We just want serial driver can be builtin for any platform, so it
>
> What would be the benefit of the user to be able to have the SPRD serial
> driver built-in on any platform?  AFAIU, it supports only Spreadtrum
> platforms.
>
Assume there is a all-in-one common kernel binary image say arm64 for
all SoC platform and all
device drivers are built as modules from different vendors for each
specific devices.
But for serial driver it is too late to be initialized as a module if
users want to check early console log.
At this circumstance vendors prefer to set their serial driver to be
built into that all-in-one image as easy
as to only set one config instead of enabling whole platform then
disabling many out of serial.

-Orson

> > should not depend on a config which can be set as 'm' (i.e. ARCH_SPRD)
> > , otherwise if the config was set as 'm', the serial driver can't be
> > selected as 'y' then.
>
> I ask about that as a reply to PATCH 1/2.
>
> > That's what I mean.
>
> > > > --- a/drivers/tty/serial/Kconfig
> > > > +++ b/drivers/tty/serial/Kconfig
> > > > @@ -1452,7 +1452,6 @@ config SERIAL_MEN_Z135
> > > >
> > > >  config SERIAL_SPRD
> > > >         tristate "Support for Spreadtrum serial"
> > > > -       depends on ARCH_SPRD
> > > >         select SERIAL_CORE
> > > >         help
> > > >           This enables the driver for the Spreadtrum's serial.
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds