RE: [PATCH v7 3/4] ARM: EXYNOS: Add platform driver support for Exynos PMU

[Pankaj Dubey <pankaj.dubey@samsung.com>]

+Arnd, Lee Jones

Hi Tomasz,

On Tuesday, August 19, 2014 Tomasz Figa wrote:

> 
> Hi Bart,
> 
> On 18.08.2014 19:42, Bartlomiej Zolnierkiewicz wrote:
> >
> > Hi,
> >
> > On Monday, July 28, 2014 08:40:52 AM Pankaj Dubey wrote:
> >> Hi Tomasz,
> >>
> >> On Friday, July 25, 2014 Tomasz Figa wrote:
> >>
> >>> To: Pankaj Dubey; 'Kukjin Kim';
> >>> linux-arm-kernel@lists.infradead.org;
> >> linux-
> >>> samsung-soc@vger.kernel.org; linux-kernel@vger.kernel.org
> >>> Cc: linux@arm.linux.org.uk; t.figa@samsung.com;
> >>> vikas.sajjan@samsung.com; joshi@samsung.com; naushad@samsung.com;
> >>> thomas.ab@samsung.com; chow.kim@samsung.com
> >>> Subject: Re: [PATCH v7 3/4] ARM: EXYNOS: Add platform driver support
> >>> for Exynos PMU
> >>>
> >>> Hi Pankaj, Kukjin,
> >>>
> >>> On 25.07.2014 07:32, Pankaj Dubey wrote:
> >>>> Hi Kukjin,
> >>>>
> >>>> On Friday, July 25, 2014 Kukjin Kim wrote:
> >>>
> >>> [snip]
> >>>
> >>>>>>
> >>>>> Looks good to me, will apply this and 4/4.
> >>>>>
> >>>>
> >>>> We need to hold these two patches until dependent patch [1] from
> >>>> Tomasz Figa gets merged.
> >>>>
> >>>> [1]: mfd: syscon: Decouple syscon interface from syscon devices
> >>>>       https://lkml.org/lkml/2014/6/24/188
> >>>
> >>> That RFC patch had few comments from Arnd needed to be addressed, so
> >>> it
> >> needs a
> >>> new revision.
> >>>
> >>> Pankaj, If I remember correctly, we had talked about this and the
> >> conclusion was that
> >>> you would take care of addressing the comments and sending new
> >>> version of
> >> the
> >>> patch. Any update on this or have I missed something?
> >>>
> >>
> >> Well, I don't think we concluded as such anything.
> >> Since this patch needs to get in so that Exynos PMU and PM related
> >> changes can go in, I discussed with you saying that I am not able to
> >> understand about Arnd's comments and if possible and time permits I
> >> will look into it. Meanwhile I got busy with some other official
> >> work, so could not get time to look into it.
> >
> > Tomasz/Pankaj, could we please get some agreement on what needs to be
> > done and who should do the pending work?
> >
> > syscon patch is blocking PMU cleanup patches which in turn are
> > blocking PMU support additions for new SoCs (Exynos5420/5800 and
> > Exynos3250 PMU patches).
> 
> Leaving alone the matter who is going to take care of it for now, the
remaining work
> to do is to further decouple syscon from struct device, which means
providing of_
> API to register a syscon provider on a device tree node even before driver
model is
> available yet.
> 

As per Arnd's comment on your RFC patch he mentioned -
"I believe the part you are missing is that with the approach I suggested,
there would be no registration function at all."

I think he is not in favor of adding such registration function at all. So
do you think
adding such function will really solve the problem?

Further even Lee Jones agreed to Arnd's point of making syscon independent
of device,
but he also mentioned that it can be done in subsequent patch.
  
So in IMHO, your RFC patch can be taken as is, and any further improvement
suggested
by Arnd can be done in subsequent patches,  because as I can see in 3.17-rc1
still
has user of syscon_regmap_lookup_by_pdevname (clps711x.c) so we can't
completely
make it independent of platform_device as of now and also the changes
required
as per Arnd's suggestions requires considerable effort and time.

> I believe it should be quite straightforward on top of my RFC and should
require only
> saving syscon's of_node directly in syscon struct, adding appropriate API
and
> extending the look-up loops to handle cases when syscon's dev is NULL.
> 
> Best regards,
> Tomasz

Thanks,
Pankaj Dubey