[PATCH v4 1/8] drm/panel: Add an API drm_panel_get_orientation() to return panel orientation

[Hsin-Yi Wang]

On Tue, Jun 7, 2022 at 3:06 AM Stephen Boyd <swboyd at chromium.org> wrote:
>
> Quoting Hsin-Yi Wang (2022-06-06 08:24:24)
> > diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> > index f634371c717a..e12056cfeca8 100644
> > --- a/drivers/gpu/drm/drm_panel.c
> > +++ b/drivers/gpu/drm/drm_panel.c
> > @@ -223,6 +223,15 @@ int drm_panel_get_modes(struct drm_panel *panel,
> >  }
> >  EXPORT_SYMBOL(drm_panel_get_modes);
> >
> > +enum drm_panel_orientation drm_panel_get_orientation(struct drm_panel *panel)
>
> Should 'panel' be marked const to indicate that it can't be modified?
>

But .get_orientation() will need to call to_XXX_panel, eg.
static inline struct boe_panel *to_boe_panel(struct drm_panel *panel)

==> .get_modes(panel) <-- can't be const.
==> drm_panel_get_orientation(panel) <-- can't be const.

We can definitely cast it in the functions, or make to_XXX_panel()
accept const, but I think this will lose the meaning of using const
anyway.

> > +{
> > +       if (panel && panel->funcs && panel->funcs->get_orientation)
> > +               return panel->funcs->get_orientation(panel);