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    SubjectRe: [PATCH 4/4] tty/serial: sh-sci: remove uneeded IS_ERR_OR_NULL calls
    Hi Linus,

    On Thu, Mar 16, 2017 at 5:38 PM, Geert Uytterhoeven
    <geert@linux-m68k.org> wrote:
    >> They actually all even do things like this in Kconfig:
    >>
    >> config SERIAL_ATMEL
    >> (...)
    >> select SERIAL_MCTRL_GPIO if GPIOLIB
    >>
    >> What stops us from removing all the stubs in
    >> drivers/tty/serial/serial_mctrl_gpio.h
    >> and just make SERIAL_MCTRL_GPIO depends on GPIOLIB?
    >
    > Removing the stubs implies adding #ifdefs to the drivers that need
    > to handle the !SERIAL_MCTRL_GPIO case.
    >
    > E.g. I don't want to break the sh-sci serial driver on SuperH platforms that
    > (a) don't select GPIOLIB, and
    > (b) don't use mtrl_gpio.

    Alternatively, after commit 22c403676dbbb7c6 ("gpio: return NULL from
    gpiod_get_optional when GPIOLIB is disabled") we might just drop the
    dependency of SERIAL_MCTRL_GPIO on GPIOLIB? Then no special handling
    is needed in drivers, as all GPIOs will just be considered not present.

    Documentation/gpio/consumer.txt rightfully sates:
    | Note that gpio_get*_optional() functions (and their managed variants), unlike
    | the rest of gpiolib API, also return NULL when gpiolib support is disabled.
    | This is helpful to driver authors, since they do not need to special case
    | -ENOSYS return codes. System integrators should however be careful to enable
    | gpiolib on systems that need it.

    drivers/tty/serial/serial_mctrl_gpio.o already compiles fine if
    CONFIG_GPIOLIB=n, which reduces its size by ca. 25%.

    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

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