Re: [PATCH 10/10] drm/panel: Make drm_panel_init() static

[Albert Esteve]

On Thu, May 7, 2026 at 4:57 PM Maxime Ripard <mripard@xxxxxxxxxx> wrote:
>
> Hi,
>
> On Thu, May 07, 2026 at 01:53:08PM +0200, Albert Esteve wrote:
> > Now that all panel drivers use devm_drm_panel_alloc(),
> > there are no external callers of drm_panel_init().
> > Make it static to prevent new users from bypassing the
> > refcounted allocation path.
> >
> > Remove stale references to drm_panel_init() in kdocs.
> >
> > Signed-off-by: Albert Esteve <aesteve@xxxxxxxxxx>
> > ---
> >  drivers/gpu/drm/display/drm_dp_helper.c | 2 +-
> >  drivers/gpu/drm/drm_panel.c             | 8 ++++----
> >  include/drm/drm_panel.h                 | 4 ----
> >  3 files changed, 5 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> > index a697cc227e289..380ebf0fad2be 100644
> > --- a/drivers/gpu/drm/display/drm_dp_helper.c
> > +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> > @@ -4626,7 +4626,7 @@ static const struct backlight_ops dp_aux_bl_ops = {
> >   * Backlight will then be handled transparently without requiring
> >   * any intervention from the driver.
> >   *
> > - * drm_panel_dp_aux_backlight() must be called after the call to drm_panel_init().
> > + * drm_panel_dp_aux_backlight() must be called after devm_drm_panel_alloc().
> >   *
> >   * Return: 0 on success or a negative error code on failure.
> >   */
> > diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> > index d1e6598ea3bc0..e3e1c5ceb8ff8 100644
> > --- a/drivers/gpu/drm/drm_panel.c
> > +++ b/drivers/gpu/drm/drm_panel.c
> > @@ -56,8 +56,9 @@ static LIST_HEAD(panel_list);
> >   * Initialize the panel structure for subsequent registration with
> >   * drm_panel_add().
> >   */
> > -void drm_panel_init(struct drm_panel *panel, struct device *dev,
> > -                 const struct drm_panel_funcs *funcs, int connector_type)
> > +static void drm_panel_init(struct drm_panel *panel, struct device *dev,
> > +                        const struct drm_panel_funcs *funcs,
> > +                        int connector_type)
> >  {
> >       if (connector_type == DRM_MODE_CONNECTOR_Unknown)
> >               DRM_WARN("%s: %s: a valid connector type is required!\n", __func__, dev_name(dev));
> > @@ -69,7 +70,6 @@ void drm_panel_init(struct drm_panel *panel, struct device *dev,
> >       panel->funcs = funcs;
> >       panel->connector_type = connector_type;
> >  }
> > -EXPORT_SYMBOL(drm_panel_init);
> >
> >  /**
> >   * drm_panel_add - add a panel to the global registry
> > @@ -708,7 +708,7 @@ EXPORT_SYMBOL(devm_drm_panel_add_follower);
> >   * A typical implementation for a panel driver supporting device tree
> >   * will call this function at probe time. Backlight will then be handled
> >   * transparently without requiring any intervention from the driver.
> > - * drm_panel_of_backlight() must be called after the call to drm_panel_init().
> > + * drm_panel_of_backlight() must be called after devm_drm_panel_alloc().
>
> I think we can drop that sentence entirely. Now that we can only get a
> panel structure through devm_drm_panel_alloc, and that it also
> initializes it, we can't call drm_panel_of_backlight before having an
> initialized drm_panel.

Makes sense, I will remove the sentence and send a v2. It probably
follows the same reasoning, but just to ensure you did not miss it:
does that apply to drm_panel_dp_aux_backlight() above too?

>
> Maxime