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    SubjectRe: [PATCH v4 00/18] mfd: demodularization of non-modular drivers
    To all recipients (therefore, not a top post ;D ),

    So far, so good. Please keep the reviews coming.

    On Mon, 17 Dec 2018, Paul Gortmaker wrote:

    > [v3 --> v4: delete now unused exit fcn from wm835x core; add more acks
    > now all in chrono order, re-test.]
    >
    > [v2 --> v3: drop diasemi commits as they will be modularized; delete
    > now unused exit fcn from wm831x core; add more acks; re-test.]
    >
    > [v1 --> v2: add some more commits as requested by Lee (MFD maintainer),
    > update the 00/NN text; re-do build and link testing on new linux-next. ]
    >
    > This group of MFD drivers are all controlled by "bool" Kconfig settings,
    > but contain various amounts of largely pointless uses of infrastructure
    > related to modular operations, even though they can't be built modular.
    >
    > We can easily remove/replace all of it. We are trying to make driver
    > code consistent with the Makefiles/Kconfigs that control them. This
    > means not using modular functions/macros for drivers that can never be
    > built as a module. Some of the downfalls this oversight leads to are:
    >
    > (1) it is easy to accidentally write unused module_exit and remove code
    > (2) it can be misleading when reading the source, thinking it can be
    > modular when the Makefile and/or Kconfig prohibit it
    > (3) it requires the include of the module.h header file which in turn
    > includes nearly everything else, thus adding a lot of CPP overhead.
    > (4) it gets copied/replicated into other drivers and spreads quickly.
    >
    > What we see in current drivers falls into one or more of the following
    > categories:
    >
    > 1) include of <linux/module.h> when it simply isn't needed
    >
    > 2) Use of MODULE_LICENSE, MODULE_DEVICE_TABLE, MODULE_AUTHOR etc.
    > macros that are no-ops for non-modular drivers.
    >
    > 3) Creation of a module_exit() function that will be compiled and
    > linked in but never actually called for non-modular drivers.
    >
    > 4) Addition of a platform_driver ".remove" function that is bound
    > into the struct but will never be called for non-module use cases.
    >
    > Solution to #1 --> #3 is simple ; we just delete the related code.
    >
    > The solution to #4 is similar - we delete the ".remove" function and
    > the binding into the platform_driver struct. However, since the same
    > ".remove" function could also be triggered by an "unbind" (such as for
    > pass-through of a device to a guest instance) - so we also explicitly
    > disable any unbind for the driver.
    >
    > The unbind mask allows us to ensure we will see if there was some odd
    > corner case out there that was relying on it. Typically it would be a
    > multi-port ethernet card passing a port through to a guest, so a
    > sensible use case in MFD drivers seems highly unlikely. This same
    > solution has already been used in multiple other mainline subsystems.
    >
    > Build testing was done on drivers/mfd for allyesconfig on x86_64, ARM
    > and ARM-64 on a recent linux-next checkout.
    >
    > Paul.
    >
    > ---
    >
    > Cc: Alessandro Rubini <rubini@gnudd.com>
    > Cc: Arnd Bergmann <arnd@arndb.de>
    > Cc: Charles Keepax <ckeepax@opensource.cirrus.com>
    > Cc: Cory Maccarrone <darkstar6262@gmail.com>
    > Cc: Davide Ciminaghi <ciminaghi@gnudd.com>
    > Cc: Dong Aisheng <dong.aisheng@linaro.org>
    > Cc: Graeme Gregory <gg@slimlogic.co.uk>
    > Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
    > Cc: Haojian Zhuang <haojian.zhuang@marvell.com>
    > Cc: Jin Park <jinyoungp@nvidia.com>
    > Cc: Jorge Eduardo Candelaria <jedu@slimlogic.co.uk>
    > Cc: Laxman Dewangan <ldewangan@nvidia.com>
    > Cc: Lee Jones <lee.jones@linaro.org>
    > Cc: Linus Walleij <linus.walleij@linaro.org>
    > Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
    > Cc: Mattias Nilsson <mattias.i.nilsson@stericsson.com>
    > Cc: Michael Hennerich <michael.hennerich@analog.com>
    > Cc: Tony Lindgren <tony@atomide.com>
    > Cc: Venu Byravarasu <vbyravarasu@nvidia.com>
    > Cc: linux-omap@vger.kernel.org
    > Cc: patches@opensource.cirrus.com
    >
    >
    > Paul Gortmaker (18):
    > mfd: aat2870-core: Make it explicitly non-modular
    > mfd: adp5520: Make it explicitly non-modular
    > mfd: as3711: Make it explicitly non-modular
    > mfd: db8500-prcmu: drop unused MODULE_ tags from non-modular code
    > mfd: htc-i2cpld: Make it explicitly non-modular
    > mfd: max8925-core: drop unused MODULE_ tags from non-modular code
    > mfd: rc5t583: Make it explicitly non-modular
    > mfd: sta2x11: drop unused MODULE_ tags from non-modular code
    > mfd: syscon: Make it explicitly non-modular
    > mfd: tps65090: Make it explicitly non-modular
    > mfd: tps65910: Make it explicitly non-modular
    > mfd: tps80031: Make it explicitly non-modular
    > mfd: wm831x-spi: Make it explicitly non-modular
    > mfd: wm831x-i2c: Make it explicitly non-modular
    > mfd: wm831x-core: drop unused module infrastructure from non-modular code
    > mfd: wm8350-i2c: Make it explicitly non-modular
    > mfd: wm8350-core: drop unused module infrastructure from non-modular code
    > mfd: wm8400-core: Make it explicitly non-modular
    >
    > drivers/mfd/aat2870-core.c | 40 +++-------------------------------------
    > drivers/mfd/adp5520.c | 30 +++++++-----------------------
    > drivers/mfd/as3711.c | 14 --------------
    > drivers/mfd/db8500-prcmu.c | 10 ++++------
    > drivers/mfd/htc-i2cpld.c | 18 +-----------------
    > drivers/mfd/max8925-core.c | 7 +------
    > drivers/mfd/rc5t583.c | 14 --------------
    > drivers/mfd/sta2x11-mfd.c | 10 ++++------
    > drivers/mfd/syscon.c | 12 +-----------
    > drivers/mfd/tps65090.c | 30 +++++-------------------------
    > drivers/mfd/tps65910.c | 18 +-----------------
    > drivers/mfd/tps80031.c | 37 ++-----------------------------------
    > drivers/mfd/wm831x-core.c | 15 ++-------------
    > drivers/mfd/wm831x-i2c.c | 20 ++------------------
    > drivers/mfd/wm831x-spi.c | 24 ++----------------------
    > drivers/mfd/wm8350-core.c | 30 ++----------------------------
    > drivers/mfd/wm8350-i2c.c | 24 +-----------------------
    > drivers/mfd/wm8400-core.c | 18 +++---------------
    > include/linux/mfd/wm831x/core.h | 1 -
    > include/linux/mfd/wm8350/core.h | 1 -
    > 20 files changed, 41 insertions(+), 332 deletions(-)
    >

    --
    Lee Jones [李琼斯]
    Linaro Services Technical Lead
    Linaro.org │ Open source software for ARM SoCs
    Follow Linaro: Facebook | Twitter | Blog

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