[PATCH v5 02/38] drm/blend: Get a rotation name from it's bitfield

From: Louis Chauvet

Date: Fri Jun 26 2026 - 23:32:29 EST


Having the rotation/reflection name from its value can be useful for
debugging purpose. Extract the rotation property table and implement
drm_get_rotation_name.

Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
---
drivers/gpu/drm/drm_blend.c | 35 ++++++++++++++++++++++++++---------
include/drm/drm_blend.h | 17 +++++++++++++++++
2 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
index 2f0d1ba285be..eecdaf623c1e 100644
--- a/drivers/gpu/drm/drm_blend.c
+++ b/drivers/gpu/drm/drm_blend.c
@@ -256,6 +256,31 @@ int drm_plane_create_alpha_property(struct drm_plane *plane)
}
EXPORT_SYMBOL(drm_plane_create_alpha_property);

+static const struct drm_prop_enum_list rotation_props[] = {
+ { __builtin_ffs(DRM_MODE_ROTATE_0) - 1, "rotate-0" },
+ { __builtin_ffs(DRM_MODE_ROTATE_90) - 1, "rotate-90" },
+ { __builtin_ffs(DRM_MODE_ROTATE_180) - 1, "rotate-180" },
+ { __builtin_ffs(DRM_MODE_ROTATE_270) - 1, "rotate-270" },
+ { __builtin_ffs(DRM_MODE_REFLECT_X) - 1, "reflect-x" },
+ { __builtin_ffs(DRM_MODE_REFLECT_Y) - 1, "reflect-y" },
+};
+
+/**
+ * drm_get_rotation_name - Return the name of a rotation
+ * @rotation: The rotation mask (DRM_MODE_ROTATE_* | DRM_MODE_REFLECT_*)
+ *
+ * Returns: the name of the rotation type (unknown) if rotation is not
+ * a known rotation/reflection
+ */
+const char *drm_get_rotation_name(unsigned int rotation)
+{
+ if (rotation < ARRAY_SIZE(rotation_props))
+ return rotation_props[rotation].name;
+
+ return "(unknown)";
+}
+EXPORT_SYMBOL(drm_get_rotation_name);
+
/**
* drm_plane_create_rotation_property - create a new rotation property
* @plane: drm plane
@@ -294,14 +319,6 @@ int drm_plane_create_rotation_property(struct drm_plane *plane,
unsigned int rotation,
unsigned int supported_rotations)
{
- static const struct drm_prop_enum_list props[] = {
- { __builtin_ffs(DRM_MODE_ROTATE_0) - 1, "rotate-0" },
- { __builtin_ffs(DRM_MODE_ROTATE_90) - 1, "rotate-90" },
- { __builtin_ffs(DRM_MODE_ROTATE_180) - 1, "rotate-180" },
- { __builtin_ffs(DRM_MODE_ROTATE_270) - 1, "rotate-270" },
- { __builtin_ffs(DRM_MODE_REFLECT_X) - 1, "reflect-x" },
- { __builtin_ffs(DRM_MODE_REFLECT_Y) - 1, "reflect-y" },
- };
struct drm_property *prop;

WARN_ON((supported_rotations & DRM_MODE_ROTATE_MASK) == 0);
@@ -309,7 +326,7 @@ int drm_plane_create_rotation_property(struct drm_plane *plane,
WARN_ON(rotation & ~supported_rotations);

prop = drm_property_create_bitmask(plane->dev, 0, "rotation",
- props, ARRAY_SIZE(props),
+ rotation_props, ARRAY_SIZE(rotation_props),
supported_rotations);
if (!prop)
return -ENOMEM;
diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h
index bebbb77a8f21..33329170aafe 100644
--- a/include/drm/drm_blend.h
+++ b/include/drm/drm_blend.h
@@ -43,6 +43,23 @@ static inline bool drm_rotation_90_or_270(unsigned int rotation)

#define DRM_BLEND_ALPHA_OPAQUE 0xffff

+const char *drm_get_rotation_name(unsigned int rotation);
+
+#define DRM_ROTATION_FMT "%s%s%s%s%s%s%s%s%s%s%s%s"
+#define DRM_ROTATION_FMT_ARGS(rot) \
+ (rot) & DRM_MODE_ROTATE_0 ? drm_get_rotation_name(0) : "", \
+ (rot) & DRM_MODE_ROTATE_0 ? " " : "", \
+ (rot) & DRM_MODE_ROTATE_90 ? drm_get_rotation_name(1) : "", \
+ (rot) & DRM_MODE_ROTATE_90 ? " " : "", \
+ (rot) & DRM_MODE_ROTATE_180 ? drm_get_rotation_name(2) : "", \
+ (rot) & DRM_MODE_ROTATE_180 ? " " : "", \
+ (rot) & DRM_MODE_ROTATE_270 ? drm_get_rotation_name(3) : "", \
+ (rot) & DRM_MODE_ROTATE_270 ? " " : "", \
+ (rot) & DRM_MODE_REFLECT_X ? drm_get_rotation_name(4) : "", \
+ (rot) & DRM_MODE_REFLECT_X ? " " : "", \
+ (rot) & DRM_MODE_REFLECT_Y ? drm_get_rotation_name(5) : "", \
+ (rot) & DRM_MODE_REFLECT_Y ? " " : ""
+
int drm_plane_create_alpha_property(struct drm_plane *plane);
int drm_plane_create_rotation_property(struct drm_plane *plane,
unsigned int rotation,

--
2.54.0