[PATCH 0/4] ARM: EXYNOS4: Support generic Power domain framework for EXYNOS4210

[Kukjin Kim]

Rafael J. Wysocki wrote:
> 
> On Saturday, August 13, 2011, Russell King - ARM Linux wrote:
> > On Sat, Aug 13, 2011 at 11:24:07PM +0200, Rafael J. Wysocki wrote:
> > > On Thursday, August 11, 2011, Chanwoo Choi wrote:
> > > > The following patch set use the generic Power domain Framework
instead of
> > > > power domain code depend of Samsung SoC.
> > > >
> > > > Chanwoo Choi (4):
> > > >   ARM: EXYNOS4: Support for generic I/O power domains on EXYNOS4210
> > > >   ARM: EXYNOS4: Support for generic Clock manipulation PM callbacks
> > > >   ARM: EXYNOS4: Delete the power-domain code depend on Samsung SoC
> > > >   ARM: EXYNOS4: Add power domain to use generic Power domain
Framework
> > > >
> > > >  arch/arm/mach-exynos4/Kconfig                      |   10 +-
> > > >  arch/arm/mach-exynos4/Makefile                     |    4 +-
> > > >  arch/arm/mach-exynos4/dev-pd.c                     |  139
--------------
> > > >  arch/arm/mach-exynos4/include/mach/pm-exynos4210.h |   52 ++++++
> > > >  arch/arm/mach-exynos4/include/mach/regs-clock.h    |    8 +
> > > >  arch/arm/mach-exynos4/mach-nuri.c                  |   21 ++-
> > > >  arch/arm/mach-exynos4/mach-smdkc210.c              |   26 ++-
> > > >  arch/arm/mach-exynos4/mach-smdkv310.c              |   23 ++-
> > > >  arch/arm/mach-exynos4/mach-universal_c210.c        |   21 ++-
> > > >  arch/arm/mach-exynos4/pm-exynos4210.c              |  189
++++++++++++++++++++
> > > >  arch/arm/mach-exynos4/pm-runtime.c                 |   56 ++++++
> > > >  arch/arm/plat-samsung/Kconfig                      |    8 -
> > > >  arch/arm/plat-samsung/Makefile                     |    4 -
> > > >  arch/arm/plat-samsung/include/plat/pd.h            |   30 ---
> > > >  arch/arm/plat-samsung/pd.c                         |   95
----------
> > > >  15 files changed, 377 insertions(+), 309 deletions(-)
> > > >  delete mode 100644 arch/arm/mach-exynos4/dev-pd.c
> > > >  create mode 100644
arch/arm/mach-exynos4/include/mach/pm-exynos4210.h
> > > >  create mode 100644 arch/arm/mach-exynos4/pm-exynos4210.c
> > > >  create mode 100644 arch/arm/mach-exynos4/pm-runtime.c
> > > >  delete mode 100644 arch/arm/plat-samsung/include/plat/pd.h
> > > >  delete mode 100644 arch/arm/plat-samsung/pd.c
> > >
> > > The patchset looks good to me, but please note that some code it
> > > is based on will most likely change in 3.2 due to this patchset:
> > >
> > > https://lkml.org/lkml/2011/8/8/420
> >
> > Err, isn't all that pm_clk stuff just duplicating what the clk API does?
> 
> I'm not sure it's duplicating anything.  Maybe it does, but it came into
> being by moving some code that were duplicated in a few places throughout
> the ARM and sh trees into one place.
> 
> > IOW, drivers _can_ (and should be) calling clk_disable() when they don't
> > need the clock running.
> 
> Drivers may not know about what to do in a given situation.  For example,
> if the system has power domains, it may be better to switch a power domain
> off instead of or in addition to disabling the clock and the driver
usually
> doesn't know about that.
> 
Hmm... Even though each driver cannot know the given situation, the driver
can know each own clock should be alive or not. I think, if clock gating
(enable, disable clock) is required, it should be handled in each driver. In
addition, the clock and power are not always one-on-one match.

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim at samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.