Re: [PATCH v2 0/2] Improve drm_of_component_probe() and move rockchip to use it

From: Liviu Dudau
Date: Wed Dec 23 2015 - 05:05:48 EST


On Wed, Dec 23, 2015 at 10:39:06AM +0100, Jean-Francois Moine wrote:
> On Tue, 22 Dec 2015 17:38:00 +0000
> Liviu Dudau <Liviu.Dudau@xxxxxxx> wrote:
>
> > On Fri, Nov 20, 2015 at 02:22:03PM +0000, Liviu Dudau wrote:
> > > Hello,
> > >
> > > This is v2 of the patchset trying to make drm_of_component_probe() cope with finding
> > > both local crtc ports and remote encoder ones. Heiko StÃbner was nice enough to test
> > > an earlier version that was patched following Russell's suggestions on rk3288, but
> > > I haven't seen any reports from iMX or Armada users.
> > >
> > > Changelog:
> > > v2: Updated the drm_of_component_probe() comment to explain why the reference count
> > > is not dropped. Fixed the compare_port() function for rockchip as described by
> > > Russell.
> > > v1: Original submission. http://lists.freedesktop.org/archives/dri-devel/2015-November/094546.html
> >
> > Gentle ping, this has now been tested by Rockchip people and fixes the earlier version
> > that had to be reverted in mainline. Can it be included in the -next somewhere?
>
> Hi Liviu,
>
> Sorry for being a bit late.
>
> I wanted to use drm_of_component_probe() for a new DRM driver, but I
> could not find any way to do it: you add the "ports" nodes as
> components while, usually, the components are the device nodes
> themselves.
>
> With this simple patch:
>
> diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
> index 493c05c..dbd2921 100644
> --- a/drivers/gpu/drm/drm_of.c
> +++ b/drivers/gpu/drm/drm_of.c
> @@ -101,7 +101,7 @@ int drm_of_component_probe(struct device *dev,
> continue;
> }
>
> - component_match_add(dev, &match, compare_of, port);
> + component_match_add(dev, &match, compare_of, port->parent);
> of_node_put(port);
> }
>
> everything is easy, my DT being like:
>
> de_controller {
> ...
> ports = <&lcd0_p>;
> };
>
> lcd_controller {
> ...
> lcd0_p: port {
> lcd0_ep: endpoint {
> remote-endpoint = <&hdmi_ep>;
> };
> };
> };
>
> What was the reason to keep the "ports" node instead of the device?

The function is an extract of common code sprinkled through a few DRM drivers,
they all used port rather than port->parent.

Have a look at my v2 where I've introduced two compare functions and also
modified the Rockchip compare_port() to use port->parent in the comparison. I
guess that should solve your problem.

Best regards,
Liviu

>
> --
> Ken ar c'hentaà | ** Breizh ha Linux atav! **
> Jef | http://moinejf.free.fr/
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