[PATCH v4 10/11] ARM: EXYNOS: Add platform driver support for Exynos PMU.
pankaj.dubey at samsung.com
Tue Jun 24 21:30:59 PDT 2014
On Wednesday, June 25 2014 Tomasz Figa write:
> On 24.06.2014 13:28, Pankaj Dubey wrote:
> > On Tuesday, June 17 2014, Tomasz Figa wrote:
> >> On 10.05.2014 08:56, Pankaj Dubey wrote:
> >>> +
> >>> + ret = platform_driver_register(&exynos_pmu_driver);
> >>> + if (ret < 0)
> >>> + goto out;
> >>> +
> >>> + exynos_pmu_pdev = platform_device_register_simple("exynos-pmu",
> >>> + NULL, 0);
> >> Hmm, I don't see the point of making this a platform driver only to
> > register respective
> >> platform device few lines below. If you take into account the patch
> >> for
> > syscon I
> >> posted as a reply to patch 06/11, you will be able to make this a
> >> normal
> > platform
> >> driver that binds to DT node directly and then register a syscon in
> >> probe
> > function
> >> above.
> > Well I updated PMU to be a syscon provider using your patch. It worked
> > I have following two points to mention here:
> > 1: For making PMU a normal platform driver, other than making PMU a
> > syscon provider we need to change PMU's DT binding. Basically we need
> > to remove "syscon"
> > as second compatibility string. I hope this should not be an issue.
> I don't see the reason for this. Could you elaborate on this?
Currently syscon driver is registered via postcore_initcall whereas exynos
arch_initcall. So if we keep syscon as second compatibility in exynos pmu
syscon will be registered first and hence only syscon will be probed.
> I know that the way Linux currently handles multiple compatible strings is
> but despite this, if you just make sure your platform driver registers
> platform driver, it should be fine.
Yes, this could be possible if I convert arch_initcall of exynos pmu to
As after converting arch_initcall to postcore_initcall, syscon driver will
not be probed
for exynos pmu node. Also as exynos pmu driver will now register itself as
I could not see any use of keeping second compatibility as "syscon" in
node. Do you think it is still required?
After removing "syscon" compatibility string from exynos pmu node, I have
S2R as well as watchdog driver functionality, which is user of regmap handle
of exynos pmu
and both are working fine on exynos5250.
> > 2: I can see for your syscon patch Arnd has some comments, hopefully
> > we can address his concern.
> Yes. I will get to it after sorting out few other things from my queue.
> Or you can do it if you want - the purpose of that RFC patch was just to
> show the idea I had in my mind.
OK, let me post exynos pmu v5, based on your patch, and then if time permits
I will have a look in it.
> Best regards,
More information about the linux-arm-kernel