Re: [RESUBMIT RFC PATCH v2 3/3] drivers: mfd: Add support for Exynos PMU driver

[Pankaj Dubey]

On 04/29/2014 02:37 AM, Catalin Marinas wrote:
> On Mon, Apr 28, 2014 at 01:26:46PM +0100, Lee Jones wrote:
> > > This patch moves Exynos PMU driver implementation from
> > > "arm/mach-exynos" to "drivers/mfd".
> > > This driver is mainly used for setting misc bits of register from PMU IP
> > > of Exynos SoC which will be required to configure before Suspend/Resume.
> > > Currently all these settings are done in "arch/arm/mach-exynos/pmu.c" but
> > > moving ahead for ARM64 based SoC support, there is a need of DT based
> > > implementation of PMU driver.
> > > This driver uses already existing DT binding information.
> > >
> > > CC: Sangbeom Kim <sbkim73@xxxxxxxxxxx>
> > > CC: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>
> > > CC: Lee Jones <lee.jones@xxxxxxxxxx>
> > > Signed-off-by: Pankaj Dubey <pankaj.dubey@xxxxxxxxxxx>
> > > ---
> > >   arch/arm/mach-exynos/Kconfig                           |    2 ++
> > >   arch/arm/mach-exynos/Makefile                          |    2 --
> > >   drivers/mfd/Kconfig                                    |    9 +++++++++
> > >   drivers/mfd/Makefile                                   |    1 +
> > >   arch/arm/mach-exynos/pmu.c => drivers/mfd/exynos-pmu.c |    0
> > >   5 files changed, 12 insertions(+), 2 deletions(-)
> > >   rename arch/arm/mach-exynos/pmu.c => drivers/mfd/exynos-pmu.c (100%)
> > So I just took a look at the code as zero changes looks suspicious to
> > me. The driver can not simply be copied and pasted into the MFD
> > subsystem in its current state.
> >
> > The fundamental question is; is this chip actually an MFD? What does
> > it do besides Power Management?
> I looked at the code briefly as well and I don't think it matches the
> mfd idea. Maybe it could be merged together with
> arch/arm/mach-exynos/pm.c and moved to drivers/power/ or a more
> appropriate directory for platform_suspend_ops.

Well I was also not quite sure about if "drivers/mfd" is proper place
for Exynos PMU, so I posted this patch as RFC.

If it does not seems matching with "drivers/mfd" idea, will it be suitable
for "drivers/power/" or should I go for something like "drivers/soc/samsung"?

Regarding your second point about merging this code with "mach-exynos/pm.c"
We have plan for this but, I would like to get it done via a separate patch 
series
as "mach-exynos/pm.c" has a lot of dependencies and requires significant
modifications. So this work can be treated as a first step towards that 
direction.

--
Best Regards,
Pankaj Dubey

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