@@ -35,6 +35,7 @@
#include <linux/export.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
+#include <video/of_videomode.h>
#include <video/videomode.h>
/**
@@ -541,6 +542,38 @@ int drm_display_mode_from_videomode(const struct videomode *vm,
EXPORT_SYMBOL_GPL(drm_display_mode_from_videomode);
#endif
+#if IS_ENABLED(CONFIG_OF_VIDEOMODE)
+/**
+ * of_get_drm_display_mode - get a drm_display_mode from devicetree
+ * @np: device_node with the timing specification
+ * @dmode: will be set to the return value
+ * @index: index into the list of display timings in devicetree
+ *
+ * This function is expensive and should only be used, if only one mode is to be
+ * read from DT. To get multiple modes start with of_get_display_timings and
+ * work with that instead.
+ */
+int of_get_drm_display_mode(struct device_node *np,
+ struct drm_display_mode *dmode, int index)
+{
+ struct videomode vm;
+ int ret;
+
+ ret = of_get_videomode(np, &vm, index);
+ if (ret)
+ return ret;
+
+ drm_display_mode_from_videomode(&vm, dmode);
+
+ pr_debug("%s: got %dx%d display mode from %s\n",
+ of_node_full_name(np), vm.hactive, vm.vactive, np->name);
+ drm_mode_debug_printmodeline(dmode);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_get_drm_display_mode);
+#endif
+
/**
* drm_mode_set_name - set the name on a mode
* @mode: name will be set in this mode
@@ -85,6 +85,7 @@ struct module;
struct drm_file;
struct drm_device;
+struct device_node;
struct videomode;
#include <drm/drm_os_linux.h>
@@ -1460,6 +1461,9 @@ drm_mode_create_from_cmdline_mode(struct drm_device *dev,
extern int drm_display_mode_from_videomode(const struct videomode *vm,
struct drm_display_mode *dmode);
+extern int of_get_drm_display_mode(struct device_node *np,
+ struct drm_display_mode *dmode,
+ int index);
/* Modesetting support */
extern void drm_vblank_pre_modeset(struct drm_device *dev, int crtc);