[PATCH v1 1/1] drm/drm_panel: Fix EXPORT of drm_panel_of_backlight() one more time

[Andy Shevchenko]

The initial commit followed by the fix didn't take into consideration the case

CONFIG_DRM_PANEL=y
CONFIG_BACKLIGHT_CLASS_DEVICE=m
CONFIG_DRM_I915=y

where symbol devm_of_find_backlight() is not reachable from DRM subsystem.
Quick fix is to avoid drm_panel_of_backlight() from exporting in such case.

Fixes: 907aa265fde6 ("drm/drm_panel: fix EXPORT of drm_panel_of_backlight")
Reported-by: Randy Dunlap <rdunlap at infradead.org>
Cc: Linus Walleij <linus.walleij at linaro.org>
Cc: Sam Ravnborg <sam at ravnborg.org>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: Thierry Reding <thierry.reding at gmail.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Sean Paul <sean at poorly.run>
Cc: David Airlie <airlied at linux.ie>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Maxime Ripard <mripard at kernel.org>
Cc: dri-devel at lists.freedesktop.org
Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
---
 drivers/gpu/drm/drm_panel.c | 2 +-
 include/drm/drm_panel.h     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index 79ff3fdf6f6e..8c7bac85a793 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -302,7 +302,7 @@ struct drm_panel *of_drm_find_panel(const struct device_node *np)
 EXPORT_SYMBOL(of_drm_find_panel);
 #endif
 
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 /**
  * drm_panel_of_backlight - use backlight device node for backlight
  * @panel: DRM panel
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 5f27b693e1a0..121f7aabccd1 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -198,7 +198,7 @@ static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
 }
 #endif
 
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
 int drm_panel_of_backlight(struct drm_panel *panel);
 #else
 static inline int drm_panel_of_backlight(struct drm_panel *panel)
-- 
2.24.0