Re: [RFC PATCH 1/2] PM / OPP: add support to specify phandle of another node for OPP

[Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>]

On 01/08/13 17:49, Stephen Warren wrote:
> On 08/01/2013 07:54 AM, Mark Rutland wrote:
> ...
>> We seem to be going over two cases, which both feel wrong to me:
>>
>> * One SoC used in multiple boards, where on some boards an OPP cannot be
>>   used because some requirement is not met. In this case, the board's
>>   dts (by including the SoC's dtsi) describes something that's not
>>   necessarily usable, and we seem to have no way to describe in the OPP
>>   table that the OPP is not usable for that board.
> 
> There are probably a lot of examples of this already. For example, for
> pinctrl, people often want the SoC .dtsi file to include "pin
> configuration nodes" (see
> Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt) for many
> common pinmux configurations in the SoC .dtsi file, so that board files
> can simply refer to the already-existing nodes rather than having to
> write everything from scratch. Obviously, not all common configurations
> are used by every board.
> 
> ...
Agreed, but I am not convinced with the comparison(pinmux and OPPs).
The main concern I have is that if some developer wants to experiment
with various configurations provided by SoC(e.g. I have seen some SoC
where the pinmux have multiple functions and you can chose one of them)
But that's not true with OPPs, if someone experiments with wrong OPP
profile, then it might damage the board permanently.

Regards,
Sudeep