Re: [PATCH 2/5] OMAP: GPIO: use pwrdmn name to find wkup dmn GPIO

[Kevin Hilman <khilman@ti.com>]

"Varadarajan, Charulatha" <charu@ti.com> writes:

> On Sat, Mar 5, 2011 at 02:21, Kevin Hilman <khilman@ti.com> wrote:
>> Charulatha V <charu@ti.com> writes:
>>
>>> In omap3, save/restore context is implemented for GPIO
>>> banks 2-6 as GPIO bank1 is in wakeup domain. Instead
>>> of identifying bank's power domain by bank id, make use
>>> of powerdomain name itself.
>>>
>>> For this, omap_hwmod_get_pwrdm() is used. omap_device_get_pwrdm()
>>> could not be used as the pwrdm information needs to be filled
>>> in pdata. But omap_device_get_pwrdm() can be used only after
>>> omap_device_build() call.
>>>
>>> Signed-off-by: Charulatha V <charu@ti.com>
>>>
>>> Tested-by: Tarun Kanti DebBarma <tarun.kanti@ti.com>
>>> (2430-SDP testing)
>>
>> I like the idea of this change, but not the implementation...
>>
>> [...]
>>
>>> @@ -1865,16 +1867,15 @@ static int workaround_enabled;
>>>  void omap2_gpio_prepare_for_idle(int off_mode)
>>>  {
>>>       int i, c = 0;
>>> -     int min = 0;
>>>
>>> -     if (cpu_is_omap34xx())
>>> -             min = 1;
>>> -
>>> -     for (i = min; i < gpio_bank_count; i++) {
>>> +     for (i = 0; i < gpio_bank_count; i++) {
>>>               struct gpio_bank *bank = &gpio_bank[i];
>>>               u32 l1 = 0, l2 = 0;
>>>               int j;
>>>
>>> +             if (!strcmp(bank->pwrdm_name, "wkup_pwrdm"))
>>> +                     continue;
>>> +
>>
>> This adds a string compare for every bank during every idle
>> transistion (and every resume.)  That's a lot of unneeded overhead.
>>
>> I'd rather see a per-bank flag 'looses_context' or something that can be
>> checked more efficiently in this fast path.  This flag can be set based
>> on the powerdomain name in the device init code.
>
> This looks better. Will do the needful.
> One question, can "looses_context" be made as part of dev_attr?

I guess that's up to Benoît.

But, I don't think that's necessary. It should be easy to set at runtime
just doing a strcmp on the powerdomain during the device init,
omap_device_build phase.

Kevin

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