[PATCH] drm: convert DT component matching to component_match_add_release()

Russell King - ARM Linux linux at armlinux.org.uk
Fri Jun 3 04:48:05 PDT 2016

On Fri, Jun 03, 2016 at 12:19:41PM +0100, Liviu Dudau wrote:
> On Fri, Jun 03, 2016 at 11:36:33AM +0100, Russell King - ARM Linux wrote:
> > On Fri, Jun 03, 2016 at 10:40:48AM +0100, Liviu Dudau wrote:
> > > On Fri, Jun 03, 2016 at 08:58:10AM +0100, Russell King wrote:
> > > > Convert DT component matching to use component_match_add_release().
> > > 
> > > Hi Russell,
> > > 
> > > Any reason for not keeping the component_match_add() calls in the drivers?
> > 
> > Sorry, I don't understand your comment.
> As in: component_match_add() already exists as a macro that calls
> component_match_add_release(), but with a NULL release function. If it
> were to be changed to pass a default release_of() function then most of
> the drivers would not have to change, right? It is just one point of
> view and I was curious if there was a reason not to choose it, as it
> would have (probably) generated a smaller delta?

And what should the calls that don't pass a DT node be called?
What happens to new users who aren't passing a DT node but use
component_match_add() ?

What you're suggesting sound totally insane to me: you're making
the change a flag-day: component_match_add() currently takes anything
as the data pointer and users can pass anything that their compare
function can handle - and changing that to a function which can only
take a device_node.  That means all non-DT users of that function
need to change at the same time.

Flag days are really bad news in kernel development (or any
distributed development project), and I won't generate a patch which
causes a flag day to occur - especially not one which impacts a large
number of users.

RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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