[PATCH] mmc: mmci: Improve runtime PM support

[ulf.hansson@stericsson.com (Ulf Hansson)]

>> Could you maybe elaborate a bit of how the power is controlled in the  
>> ARM dev boards? Would it be possible to control such a switch in "GPIO"  
>> manner instead? For example via the vdd_handler or similar?
>>
>> I will also think if and see if is feasible to re-design and see if this  
>> hole feature can be controlled by the variant struct instead. My feeling  
>> is although it can be kind of messy. But let's see...
> 
> The MCIPWR register contains two bits to control _the_ _power_ _state_.
> See Table A-4: the MCIPWR signal.  See section 2.2.2.  See section 3.3.1.
> 
> The MCIPWR signal controls the external power switch.  This is the only
> signal for it.  This is the only connection for it.  There is no other
> control form for this power switch.
> 

Then we are only left to use the variant struct I believe. In principle, 
a flag in the variant struct, could indicate whether it is OK to disable 
the vcore regulator and thus clear the MCIPWR when doing runtime_suspend.

How do you feel about this kind of approach to find a solution?

BR
Ulf Hansson