[PATCH V2 7/9] drm/bridge: ptn3460: add drm_panel controls

[Ajay kumar]

Sorry for the previous reply,

Here goes the full explaination:

> Rob,
>
> On Tue, Apr 22, 2014 at 5:04 PM, Rob Clark <robdclark at gmail.com> wrote:
>> So what about, rather than adding drm_panel support to each bridge
>> individually, we introduce a drm_panel_bridge (with a form of
>> chaining).. ie:
>>
>>   struct drm_panel_bridge {
>>     struct drm_bridge base;
>>     struct drm_panel *panel;
>>     struct drm_bridge *bridge; /* optional */
>>   };
>>
>>   static void drm_panel_bridge_enable(struct drm_bridge *bridge)
>>   {
>>     struct drm_panel_bridge *pb = to_panel_bridge(bridge);
>>     if (pb->bridge)
>>       pb->bridge->funcs->enable(pb->bridge);
>>     pb->panel->funcs->enable(pb->panel);
>>   }
>>
We cannot call them like this from crtc helpers in the order you mentioned,
since each individual bridge chip expects the panel controls at
different places.
I mean,
-- sometimes panel controls needs to be done before bridge
controls(ptn3460: before RST_N and PD_N)
-- sometimes in between the bridge controls (ps8622: one panel control
before SLP_N and one after SLP_N)
-- sometimes panel controls needs to be done after bridge controls.

So, putting these drm_panel controls inside individual bridge drivers will work,
but keeping them in crtc_helpers might break stuff.

Thanks and regards,
Ajay Kumar