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    SubjectRe: [Question] orphan platform data header
    On Sun, Jul 21, 2019 at 6:10 PM Arnd Bergmann <arnd@arndb.de> wrote:
    >
    > On Sun, Jul 21, 2019 at 5:45 AM Masahiro Yamada
    > <yamada.masahiro@socionext.com> wrote:
    > > On Sat, Jul 20, 2019 at 10:55 PM Arnd Bergmann <arnd@arndb.de> wrote:
    > > > On Sat, Jul 20, 2019 at 5:26 AM Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
    > > > > So, what shall we do?
    > > > >
    > > > > Drop the board-file support? Or, keep it
    > > > > in case somebody is still using their board-files
    > > > > in downstream?
    > >>
    > > > For this file, all boards got converted to DT, and the old setup
    > > > code removed in commit ebc278f15759 ("ARM: mvebu: remove static
    > > > LED setup for netxbig boards"), four years ago, so it's a fairly
    > > > easy decision to make it DT only.
    > >
    > > I see another case, which is difficult
    > > to make a decision.
    > >
    > > For example, drivers/spi/spi-tle62x0.c
    > >
    > > This driver supports only board-file, but the board-file
    > > is not found in upstream.
    > >
    > > Unless I am terribly missing something,
    > > there is no one who passes tle62x0_pdata
    > > to this driver.
    > >
    > > $ git grep tle62x0_pdata
    > > drivers/spi/spi-tle62x0.c: struct tle62x0_pdata *pdata;
    > > include/linux/spi/tle62x0.h:struct tle62x0_pdata {
    > >
    > > But, removing board-file support
    > > makes this driver completely useless...
    >
    > Adding Ben Dooks to Cc.
    >
    > I suspect this driver is completely obsolete and should be removed.
    >
    > For some reason, it's not an SPI controller driver like all the other
    > files in that directory, but implements low-level access to the state
    > of a particular SPI device.
    >
    > However, there should not really be a low-level driver for it that
    > just exports the pins to user space. It should either be a gpiolib
    > driver to let other drivers talk to the pins, or a high-level driver that
    > exposes the intended functionality (watchdog, regulator, ...)
    > to those respective subsystems.
    >
    > Arnd


    Another example that I have no idea
    how it works:

    drivers/net/hamradio/yam.c

    yam_ioctl() reads data from user-space,
    but the data structures for ioctl are
    defined in include/linux/yam.h

    This header is not exported to user-space
    since it is outside of the uapi directory.

    I dug the git history, but it has never
    exported to user-space in the past.

    I do not know how user-space programs can
    pass-in data to the kernel.

    If we want to fix this, we could move it
    to include/uapi/linux/yam.h

    But, if nobody has reported any problem about this,
    it might be a good proof that nobody is using this driver.

    Maybe, can we simply drop odd drivers??


    --
    Best Regards
    Masahiro Yamada

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