[PATCH RESEND] ARM: OMAP2+: Fix Wake-up power domain power status

[Shilimkar, Santosh]

On Mon, Jul 2, 2012 at 9:47 PM, Jon Hunter <jon-hunter at ti.com> wrote:
>
> On 06/29/2012 11:27 PM, Shilimkar, Santosh wrote:
>> + Paul, Rajendra,
>>
>> On Sat, Jun 30, 2012 at 2:34 AM, Jon Hunter <jon-hunter at ti.com> wrote:
>>> Note: Re-sending with updated kernel doc.
>>>
>>> The wake-up power domain is an alway-on power domain and so this power domain
>>> does not have a power state status (PM_PWSTST_xxx) register that indicates the
>>> current state. However, during the registering of the wake-up power domain the
>>> state of the domain is queried by calling pwrdm_read_pwrst(). This actually
>>> tries to read a register that does not exist and returns a value of 0 that
>>> indicates that the current state is OFF. The OFF state count of the wake-up
>>> power domain is then set to 1 and the current state to OFF. Both of which are
>>> incorrect.
>>>
>>> To fix this, if a power domain only supports the ON state, do not attempt to
>>> read the power state status register and simply return ON as the current power
>>> state.
>>>
>>> This is based upon Tony's current linux-omap master branch.
>>>
>>> Testing:
>>> - Boot tested on OMAP4460 panda.
>>> - Boot tested on OMAP3430 beagle and validated CORE RET still working (using
>>>  Paul's 32k timer patch [1]).
>>>
>>> [1] http://marc.info/?l=linux-omap&m=134000053229888&w=2
>>>
>>> Signed-off-by: Jon Hunter <jon-hunter at ti.com>
>>> ---
>>>  arch/arm/mach-omap2/powerdomain.c |    6 +++++-
>>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
>>> index eefe179..69b36e1 100644
>>> --- a/arch/arm/mach-omap2/powerdomain.c
>>> +++ b/arch/arm/mach-omap2/powerdomain.c
>>> @@ -526,7 +526,8 @@ int pwrdm_read_next_pwrst(struct powerdomain *pwrdm)
>>>  *
>>>  * Return the powerdomain @pwrdm's current power state.        Returns -EINVAL
>>>  * if the powerdomain pointer is null or returns the current power state
>>> - * upon success.
>>> + * upon success. Note that if the power domain only supports the ON state
>>> + * then just return ON as the current state.
>>>  */
>>>  int pwrdm_read_pwrst(struct powerdomain *pwrdm)
>>>  {
>>> @@ -535,6 +536,9 @@ int pwrdm_read_pwrst(struct powerdomain *pwrdm)
>>>        if (!pwrdm)
>>>                return -EINVAL;
>>>
>>> +       if (pwrdm->pwrsts == PWRSTS_ON)
>>> +               return PWRDM_POWER_ON;
>>> +
>> The patch as such is correct but just wondering whether we should
>> have some flag rather than above check.
>
> I was wondering that too. I opted not to add a flag because there is
> only one such power domain that needs it.
>
I agree with you.
Acked-by: Santosh Shilimkar <santosh.shilimkar at ti.com>