[RFC PATCH 05/11] mfd: omap: control: core system control driver

[Shilimkar, Santosh]

On Fri, Jun 1, 2012 at 7:29 PM, Tony Lindgren <tony at atomide.com> wrote:
> * Cousson, Benoit <b-cousson at ti.com> [120529 06:29]:
>> On 5/28/2012 1:35 PM, Eduardo Valentin wrote:
>> >>
>> >>Mmm, we can have up to 4 control module instances in OMAP4.
>> >>
>> >>Well, I'm not sure it worth considering them as separate devices. Is
>> >>that your plan as well?
>> >
>> >At least for now I was focusing on the ctrl_module_core ...
>>
>> OK, that's a good start already :-)
>>
>> >>But since they all have different base address, it will be trick to
>> >>handle them with only a single entry.
>> >
>> >Indeed. We can always add the support latter on.
>> >
>> >I am not sure what would be the best way to handle those instances though,
>> >and how they are going to expose APIs. Would need to have an instance bound
>> >to API set?
>>
>> We should not go to that path I guess. We should have an API at
>> children level independent of the underlying control module
>> partitioning.
>
> These should be separate driver instances for the control modules.
>
> And then the ioremapped area should ignore at least the padconf
> registers so drivers/pinctrl/pinctrl-simple can handle those. There
> should not be any dependencies to the SCM driver from pinctrl-simple,
> the core SCM driver can manage the clocks and trigger the save of
> padconf regs.
>
> Also we should allow MMC driver handle the MMC specific registers
> and USB driver(s) handle the USB specific registers if possible. Those
> should not live under drivers/mfd unless there are some dependencies
> other than trying to ioremap the whole SCM module instead of ioremapping
> in each driver.
>
> We can have a static map for the SCM, so ioremapping each driver
> individually should not be an issue.
>
This sounds a good idea. With this we may not even need a core control
module drivers if all the individual drivers take care of the registers they
care. Mapping shouldn't be a problem as you mentioned.

Regards
Santosh