Fix the compile-time warnings

  drivers/gpu/drm/drm_panel.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
  drivers/gpu/drm/drm_panel_backlight_quirks.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
  drivers/gpu/drm/drm_panel_orientation_quirks.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
  drivers/gpu/drm/panel/panel-samsung-s6e63m0.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: a934a57a42f6 ("scripts/misc-check: check missing #include <linux/export.h> when W=1")
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250612121633.229222-8-tzimmermann@suse.de

Use firmware node based lookups for panel followers, to make the code
independent of OF and device tree, and make it work also for ACPI with
an appropriate _DSD.

ASL example:

	Package (0x02)
	{
		"panel", \_SB.PCI0.GFX0.LCD0
	}

v2:
- Update comments (Doug, Arun)
- s/IS_ERR_OR_NULL/IS_ERR/ (Doug)

Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Neil Armstrong <neil.armstrong@linaro.org>
Cc: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Lee Shawn C <shawn.c.lee@intel.com>
Tested-by: Lee Shawn C <shawn.c.lee@intel.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Arun R Murthy <arun.r.murthy@intel.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250610094132.3240567-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Add a helper to wrap OF-specific calls in drm_panel_add_follower() in
preparation for adding an ACPI equivalent in the future. No functional
changes.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250522100036.2529624-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Now there are no users of the return value of the drm_panel_prepare(),
drm_panel_unprepare(), drm_panel_enable() and drm_panel_disable() calls.
Usually these calls are performed from the atomic callbacks, where it is
impossible to return an error. Stop returning error codes and return
void instead.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250401-panel-return-void-v1-7-93e1be33dc8d@oss.qualcomm.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Move helpers outside of CONFIG_OF, so basic allocation also works
without it.

Fixes: ed9c594d495d ("drm/panel: Add new helpers for refcounted panel allocatons")
Fixes: dcba396f6907 ("drm/panel: Add refcount support")
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/nyrjnvctqnk6f3x5q7rlmy5nb7iopoti56pgh43zqknici5ms4@cibpldh7epra
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

Start moving to the new refcounted allocations using
the new API devm_drm_panel_alloc(). Deprecate any other
allocation.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Anusha Srivatsa <asrivats@redhat.com>
Link: https://lore.kernel.org/r/20250331-b4-panel-refcounting-v4-3-dad50c60c6c9@redhat.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>

Allocate panel via reference counting. Add _get() and _put() helper
functions to ensure panel allocations are refcounted. Avoid use after
free by ensuring panel pointer is valid and can be usable till the last
reference is put.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Anusha Srivatsa <asrivats@redhat.com>
Link: https://lore.kernel.org/r/20250331-b4-panel-refcounting-v4-2-dad50c60c6c9@redhat.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>

Introduce reference counted allocations for panels to avoid
use-after-free. The patch adds the macro devm_drm_bridge_alloc()
to allocate a new refcounted panel. Followed the documentation for
drmm_encoder_alloc() and devm_drm_dev_alloc and other similar
implementations for this purpose.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Anusha Srivatsa <asrivats@redhat.com>
Link: https://lore.kernel.org/r/20250331-b4-panel-refcounting-v4-1-dad50c60c6c9@redhat.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>

Having an DRM_MODE_CONNECTOR_Unknown connector type is considered bad, and
drm_panel_bridge_add_typed() and derivatives are deprecated for this.

drm_panel_init() won't prevent initializing a panel with a
DRM_MODE_CONNECTOR_Unknown connector type. Luckily there are no in-tree
users doing it, so take this as an opportinuty to document a valid
connector type must be passed.

Returning an error if this rule is violated is not possible because
drm_panel_init() is a void function. Add at least a warning to make any
violations noticeable, especially to non-upstream drivers.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250214-drm-assorted-cleanups-v7-5-88ca5827d7af@bootlin.com

The use of of_property_read_bool() for non-boolean properties is
deprecated in favor of of_property_present() when testing for property
presence.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241104190636.274926-1-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>