Subject: Re: [PATCH 2/2] platform: Facilitate the creation of pseudo-platform buses

From: Kevin Hilman <[email-masked]>
Date: Mon, 23 Aug 2010 07:53:40 -0700

Grant Likely <[email-masked]> writes:

>>> If the override is global to the platform_bus_type, then the model
>>> will not scale.
>>
>> It will not scale any more (or less) than the current functionality of
>> the driver model which handles this globally.  Again, if scalabilty
>> becomes a problem down the road, lets fix it then.
>
> Alright, I can agree to that.  I do agree that the runtime override is
> far and away better than the weak symbol approach.  However, there
> needs to be some very clear rules in place for users of the override,
> namely that users must understand that they are stewards of the
> platform_bus_type, and must take care to preserve the default
> behaviour for "uninteresting" devices.

Completely agree here.

Any overrides of the dev_pm_ops functions that do not also call the
pm_generic_* functions (or their equivalents) should be suspect.

I'll post a proposal for a runtime override shortly.

> Also, the expectation should be that it is a temporary measure until a
> better abstraction is implemented.  It might be that a separate
> bus_type is the way to go (if the multiple driver registration problem
> can be solved) or it might be a way to differentiate pm_ops either
> per-device or per-parent.  I'm not sure, but I'm starting on an OMAP
> project soon, so I may very well end up working on this.

Yes, I'll be glad to work on this too, but first I need to get through
reviewing the backlog of all the OMAP drivers we're converting to
runtime PM.

Kevin