[RE: [PATCH v2 00/22] mfd: demodularization of non-modular drivers] On 05/12/2018 (Wed 12:01) Steve Twiss wrote: > Hi Paul, > > On 03 December 2018 04:23, Paul Gortmaker wrote: > > > Subject: [PATCH v2 00/22] mfd: demodularization of non-modular drivers > > > > [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. > > For the DA9052 and DA9055, changes: > > - drivers/mfd/da9052-core.c | 11 ----------- > - drivers/mfd/da9052-i2c.c | 22 ++------------------- > - drivers/mfd/da9052-irq.c | 1 - > - drivers/mfd/da9052-spi.c | 22 ++------------------- > - drivers/mfd/da9055-core.c | 13 ++----------- > - drivers/mfd/da9055-i2c.c | 24 ++--------------------- > > The responsibility can fall back to Dialog for these changes. We will > submit Kconfig patches for these and make them explicitly non-modular. > This will remove the ambiguity caused by the Kconfig bool options. [typo noted: non-modular ---> modular] Great, I'll look forward to seeing those patches to convert these drivers to modular in the near future, and I'll not re-send mine. Thanks, P. -- > > Regards, > Steve > > > 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: Arnd Bergmann <arnd@xxxxxxxx> > > Cc: Cory Maccarrone <darkstar6262@xxxxxxxxx> > > Cc: David Dajun Chen <dchen@xxxxxxxxxxx> > > Cc: Dong Aisheng <dong.aisheng@xxxxxxxxxx> > > Cc: Eric Miao <eric.miao@xxxxxxxxxxx> > > Cc: Graeme Gregory <gg@xxxxxxxxxxxxxxx> > > Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx> > > Cc: Haojian Zhuang <haojian.zhuang@xxxxxxxxxxx> > > Cc: Jin Park <jinyoungp@xxxxxxxxxx> > > Cc: Jorge Eduardo Candelaria <jedu@xxxxxxxxxxxxxxx> > > Cc: Laxman Dewangan <ldewangan@xxxxxxxxxx> > > Cc: Lee Jones <lee.jones@xxxxxxxxxx> > > Cc: Linus Walleij <linus.walleij@xxxxxxxxxx> > > Cc: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> > > Cc: Mattias Nilsson <mattias.i.nilsson@xxxxxxxxxxxxxx> > > Cc: Michael Hennerich <michael.hennerich@xxxxxxxxxx> > > Cc: Mike Rapoport <mike@xxxxxxxxxxxxxx> > > Cc: Tony Lindgren <tony@xxxxxxxxxxx> > > Cc: Venu Byravarasu <vbyravarasu@xxxxxxxxxx> > > Cc: linux-omap@xxxxxxxxxxxxxxx > > Cc: patches@xxxxxxxxxxxxxxxxxxxxx > > Cc: Support Opensource <support.opensource@xxxxxxxxxxx> > > > > > > Paul Gortmaker (22): > > mfd: aat2870-core: Make it explicitly non-modular > > mfd: adp5520: Make it explicitly non-modular > > mfd: as3711: Make it explicitly non-modular > > mfd: da903x: Make it explicitly non-modular > > mfd: da9052-*: Make it explicitly non-modular > > mfd: da9055-i2c: Make it explicitly non-modular > > mfd: da9055-core: 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_ tags from non-modular code > > mfd: wm8350-i2c: Make it explicitly non-modular > > mfd: wm8350-core: drop unused MODULE_ tags 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/da903x.c | 26 +++---------------------- > > drivers/mfd/da9052-core.c | 11 ----------- > > drivers/mfd/da9052-i2c.c | 22 ++------------------- > > drivers/mfd/da9052-irq.c | 1 - > > drivers/mfd/da9052-spi.c | 22 ++------------------- > > drivers/mfd/da9055-core.c | 13 ++----------- > > drivers/mfd/da9055-i2c.c | 24 ++--------------------- > > 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 | 7 ++----- > > drivers/mfd/wm831x-i2c.c | 20 ++------------------ > > drivers/mfd/wm831x-spi.c | 24 ++--------------------- > > drivers/mfd/wm8350-core.c | 6 ++---- > > drivers/mfd/wm8350-i2c.c | 24 +---------------------- > > drivers/mfd/wm8400-core.c | 18 +++--------------- > > include/linux/mfd/da9052/da9052.h | 1 - > > 26 files changed, 52 insertions(+), 407 deletions(-) > > > > -- > > 2.7.4 >
