Re: [PATCH 4/4] drm/panel: Add helper for simple panel connector

[Noralf TrÃnnes]

Den 07.05.2016 11:59, skrev Daniel Vetter:
> On Fri, May 6, 2016 at 9:45 PM, Noralf TrÃnnes <noralf@xxxxxxxxxxx> wrote:
> > In the discussion following the "no more fbdev drivers" call, someone
> > pointed me to drm_panel. It had function hooks that I needed, so I built
> > tinydrm around it. If this is misusing drm_panel, it shouldn't be too
> > difficult to drop it.
> >
> > Actually I could just do this:
> >
> > struct tinydrm_funcs {
> >          int (*prepare)(struct tinydrm_device *tdev);
> >          int (*unprepare)(struct tinydrm_device *tdev);
> >          int (*enable)(struct tinydrm_device *tdev);
> >          int (*disable)(struct tinydrm_device *tdev);
> >          int (*dirty)(struct drm_framebuffer *fb, void *vmem, unsigned flags,
> >                       unsigned color, struct drm_clip_rect *clips,
> >                       unsigned num_clips);
> > };
> >
> >
> > When it comes to the simple connector, one solution could be to extend
> > drm_simple_display_pipe to embed a connector with (optional) modes:
> >
> >   struct drm_simple_display_pipe {
> > -        struct drm_connector *connector;
> > +        struct drm_connector connector;
> > +        const struct drm_display_mode *modes;
> > +        unsigned int num_modes;
> >   };
> >
> > And maybe optional detect and get_modes hooks:
> >
> >   struct drm_simple_display_pipe_funcs {
> > +        enum drm_connector_status detect(struct drm_connector *connector,
> > +                                         bool force);
> > +        int (*get_modes)(struct drm_connector *connector);
> >   };
> >
> >   int drm_simple_display_pipe_init(struct drm_device *dev,
> >                                    struct drm_simple_display_pipe *pipe,
> >                                    struct drm_simple_display_pipe_funcs
> > *funcs,
> >                                    const uint32_t *formats,
> >                                    unsigned int format_count,
> > -                                 struct drm_connector *connector);
> > +                                 int connector_type);
> Tbh I really like that simple_display_pipe is split after the encoder.
> This allows us to easily splice in a drm_bridge (which will register
> the drm_connector itself) with very little work. And even if there's
> not a full-blown bridge you might have different connectors and
> things.
>
> > Another solution is to create a simple connector with modes:
> >
> > struct drm_simple_connector {
> >          struct drm_connector connector;
> >          const struct drm_display_mode *modes;
> >          unsigned int num_modes;
> > };
> >
> > struct drm_connector *drm_simple_connector_create(struct drm_device *dev,
> >          const struct drm_display_mode *modes, unsigned int num_modes,
> >          int connector_type);
> Yeah, this makes more sense to me, but then we're kinda reinventing
> something like simple-panel.c with this. Otoh right now with
> smple_display_pipe it's not possible to wire up the panel callbacks
> easily, so maybe it should be a drm_bridge. Or we just leave this code
> in tinydrm and extract it when someone else has a need for it?

Yes, since there's no obvious use for such a simple controller I'll just 
put it in tinydrm.

Noralf.