[PATCH] OMAP4: clockdomain: Follow recommended enable sequence

[Santosh Shilimkar]

Paul,
On 4/4/2011 12:17 PM, Paul Walmsley wrote:
> On Fri, 1 Apr 2011, Rajendra Nayak wrote:
>
>> On 4/1/2011 8:21 PM, Rajendra Nayak wrote:
>>>>> In omap_hwmod.c:_enable(), what do you think about:
>>>>>
>>>>> 1. saving the current idle mode of the clockdomain,
>>>>>
>>>>> 2. forcing the clockdomain to software-supervised wakeup.
>>>>>
>>>>> 3. enabling clocks and waiting for the module as we currently do, then
>>>>>
>>>>> 4. switching the clockdomain's idle mode back to its original state?
>>>>>
>>>>> Seems like that would be a reasonable approach for the short term, at
>>>>> least for drivers that have been converted to PM runtime.
>>>>
>>>> Ok, I'll try and get some RFC patches in these lines soon.
>>>
>>> I tried some of what you were suggesting here and it seems to
>>> work well, like you said, for the drivers which are converted
>>> to PM runtime.
>>>
>>> Now the issue seems to be, how do we handle the ones which
>>> are *still* using clock framework to enable main clocks and
>>> are yet to be converted to PM runtime.
>>>
>>> One such, MMC, is showing me issues on OMAP4 even at boot
>>> and causes a crash.
>>>
>>> Its a different thing that some of these drivers which use
>>> direct clock calls are working by fluke on OMAP4 since the
>>> clock framework does not even wait for the modules to become
>>> accessible after the clock enable.
>>>
>>> I know the right way seems to be to get all these drivers
>>> converted to PM runtime, but that might take sometime.
>>
>> One way I am able to get this working (atleast MMC)
>> is by preventing the clock domain belonging to MMC module
>> from being programmed into HW_SUP mode.
>
> What programs the OMAP4 clockdomains into hwsup mode in the first place?

This is done as part of the OMAP4 PM series.

Regards
Santosh