[PATCH v5 03/11] soc: renesas: rcar-sysc: Add DT support for SYSC PM domains

[Ulf Hansson]

On 18 April 2016 at 15:39, Geert Uytterhoeven <geert at linux-m68k.org> wrote:
> Hi Ulf,
>
> On Mon, Apr 18, 2016 at 2:59 PM, Geert Uytterhoeven
> <geert at linux-m68k.org> wrote:
>> On Mon, Apr 18, 2016 at 2:21 PM, Ulf Hansson <ulf.hansson at linaro.org> wrote:
>>> [...]
>>>
>>>> +
>>>> +static bool rcar_sysc_active_wakeup(struct device *dev)
>>>> +{
>>>> +       return true;
>>>
>>> I am interested to know why this is always returning true. Perhaps you
>>> can elaborate a bit on that?
>>
>> Too many copying from old shmobile PM Domain code?
>> Honestly, I don't know...
>>
>> Perhaps Rafael still remembers the original rationale, as git history for
>> commit e3e0109138376bb2 ("ARM / shmobile: Support for I/O power domains for
>> SH7372 (v9)") doesn't have it.
>>
>> Google did find: https://lkml.org/lkml/2011/6/30/471
>>
>> Do we still need this at all? I.e. aren't PM Domains containing wake-up
>> devices kept powered automatically during system suspend?
>
> No they aren't. So for pm-rmobile we do need it.

I don't quite understand why genpd should need to treat all devices
within the same domain exactly the same, it seems suboptimal.

I guess it would be more clever to allow this to be controlled on per
device basis instead, so let's say from each driver.

>
> For rcar-sysc it's different: as no PM Domain contains wake-up devices
> (all I/O devices are in the always-on power area), we don't need the callback.
> Will drop it in v6.

Okay, great!

Kind regards
Uffe