[PATCHv2 04/19] ARM: OMAP4: PM: save/restore all DPLL settings in OFF mode

Kevin Hilman khilman at ti.com
Thu May 17 12:37:42 EDT 2012


"Shilimkar, Santosh" <santosh.shilimkar at ti.com> writes:

> On Thu, May 17, 2012 at 12:34 PM, Shilimkar, Santosh
> <santosh.shilimkar at ti.com> wrote:
>> On Thu, May 17, 2012 at 4:12 AM, Kevin Hilman <khilman at ti.com> wrote:
>>> Tero Kristo <t-kristo at ti.com> writes:
>>>
>>>> From: Rajendra Nayak <rnayak at ti.com>
>>>>
>>>> SAR/ROM code restores only CORE DPLL to its original state
>>>> post wakeup from OFF mode.
>>>> The rest of the DPLL's in OMAP4 platform (MPU/IVA/ABE/USB/PER)
>>>> are saved and restored here during an OFF transition.
>>>>
>>>> [nm at ti.com: minor cleanups]
>>>> Signed-off-by: Nishanth Menon <nm at ti.com>
>>>> Signed-off-by: Rajendra Nayak <rnayak at ti.com>
>>>> Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
>>>> Signed-off-by: Tero Kristo <t-kristo at ti.com>
>>>
>>> Some general comments:
>>>
>>> - the register dump/print doesn't belong here.  If needed, should be a
>>>  debug feature if needed.
>>>
>>> - Rather than hooking into omap4_enter_lowpower(), should use
>>>  the cluster PM enter/exit notifier chain.
>>>
>> This is again specific to device OFF only and not related to CPU
>> cluster state as such. So I don't think notifiers should be used here.
>>
>> O.w even when we attempt just MPU OSWR C-state, all these functions will
>> get called in notifier chain.
>>
> Just a thought, we can have a separate notifier chain for device OFF. It can
> allow use to get rid of 'enable_off_mode" kind of flags and can be
> used by many drivers too.

Yes, I like this idea.

It allows a much cleaner collection of all the activities needed for
device off.

Kevin



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