[PATCH] net: davinci_emac: Add pre_open, post_stop platform callbacks

[Mark A. Greer]

On Fri, May 04, 2012 at 07:31:30AM -0700, Kevin Hilman wrote:
> "Bedia, Vaibhav" <vaibhav.bedia at ti.com> writes:

Hi Kevin.

> > If it does, perhaps there should some other mechanism for letting
> > users control the system behavior.
> 
> Come to think of it, the right solution here is probably to use runtime
> PM.  We could then to add some custom hooks for davinci_emac in the
> device code to use enable_hlt/disable_hlt based on activity.

That was my first thought, actually, but that only works if its
okay for the driver to call enable_hlt/disable_hlt directly (i.e.,
have runtime_suspend() call enable_hlt() and runtime_resume() call
disable_hlt()).  However, I assumed it would _not_ be acceptable for
the driver to issue those calls directly.  Its a platform-specific
issue that we shouldn't be polluting the driver with and there are
currently no drivers that call them under the drivers directory.

If its not okay to call enable_hlt/disable_hlt directly, then we still
need callback hooks to the plaform code (i.e., some version of this
patch).

> In order to do that though, the davinci_emac driver needs to be runtime
> PM converted.

We probably should pm_runtime-ize the driver either way but we need
to resolve the question of whether its okay for the driver to call
enable_hlt/disable_hlt directly or not.  If it is okay, we call them
in runtime_suspend/resume.  If it isn't okay, then we still need 
platform callback hooks.

Mark