[PATCH 06/19] drm/blend: Add a generic alpha property

[Maxime Ripard]

Some drivers duplicate the logic to create a property to store a per-plane
alpha.

Let's create a helper in order to move that to the core.

Cc: Boris Brezillon <boris.brezillon at free-electrons.com>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
---
 Documentation/gpu/kms-properties.csv |  2 +-
 drivers/gpu/drm/drm_atomic.c         |  4 ++++-
 drivers/gpu/drm/drm_atomic_helper.c  |  1 +-
 drivers/gpu/drm/drm_blend.c          | 32 +++++++++++++++++++++++++++++-
 include/drm/drm_blend.h              |  1 +-
 include/drm/drm_plane.h              |  6 +++++-
 6 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/Documentation/gpu/kms-properties.csv b/Documentation/gpu/kms-properties.csv
index 927b65e14219..a3c3969c1992 100644
--- a/Documentation/gpu/kms-properties.csv
+++ b/Documentation/gpu/kms-properties.csv
@@ -99,5 +99,5 @@ radeon,DVI-I,“coherent”,RANGE,"Min=0, Max=1",Connector,TBD
 ,,"""underscan vborder""",RANGE,"Min=0, Max=128",Connector,TBD
 ,Audio,“audio”,ENUM,"{ ""off"", ""on"", ""auto"" }",Connector,TBD
 ,FMT Dithering,“dither”,ENUM,"{ ""off"", ""on"" }",Connector,TBD
-rcar-du,Generic,"""alpha""",RANGE,"Min=0, Max=255",Plane,TBD
+,,"""alpha""",RANGE,"Min=0, Max=255",Plane,Opacity of the plane from transparent (0) to opaque (255)
 ,,"""colorkey""",RANGE,"Min=0, Max=0x01ffffff",Plane,TBD
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index c2da5585e201..ade18cf62c89 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -749,6 +749,8 @@ static int drm_atomic_plane_set_property(struct drm_plane *plane,
 		state->src_w = val;
 	} else if (property == config->prop_src_h) {
 		state->src_h = val;
+	} else if (property == plane->alpha_property) {
+		state->alpha = val;
 	} else if (property == plane->rotation_property) {
 		if (!is_power_of_2(val & DRM_MODE_ROTATE_MASK))
 			return -EINVAL;
@@ -810,6 +812,8 @@ drm_atomic_plane_get_property(struct drm_plane *plane,
 		*val = state->src_w;
 	} else if (property == config->prop_src_h) {
 		*val = state->src_h;
+	} else if (property == plane->alpha_property) {
+		*val = state->alpha;
 	} else if (property == plane->rotation_property) {
 		*val = state->rotation;
 	} else if (property == plane->zpos_property) {
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 71d712f1b56a..018993df4c18 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3372,6 +3372,7 @@ void drm_atomic_helper_plane_reset(struct drm_plane *plane)
 
 	if (plane->state) {
 		plane->state->plane = plane;
+		plane->state->alpha = 255;
 		plane->state->rotation = DRM_MODE_ROTATE_0;
 	}
 }
diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
index 2e5e089dd912..8eea2a8af458 100644
--- a/drivers/gpu/drm/drm_blend.c
+++ b/drivers/gpu/drm/drm_blend.c
@@ -104,6 +104,38 @@
  */
 
 /**
+ * drm_plane_create_alpha_property - create a new alpha property
+ * @plane: drm plane
+ * @alpha: initial value of alpha, from 0 (transparent) to 255 (opaque)
+ *
+ * This function initializes a generic, mutable, alpha property and
+ * enables support for it in the DRM core.
+ *
+ * Drivers can then attach this property to their plane to enable
+ * support for configurable plane alpha.
+ *
+ * Returns:
+ * 0 on success, negative error code on failure.
+ */
+int drm_plane_create_alpha_property(struct drm_plane *plane, u8 alpha)
+{
+	struct drm_property *prop;
+
+	prop = drm_property_create_range(plane->dev, 0, "alpha", 0, 255);
+	if (!prop)
+		return -ENOMEM;
+
+	drm_object_attach_property(&plane->base, prop, alpha);
+	plane->alpha_property = prop;
+
+	if (plane->state)
+		plane->state->alpha = alpha;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_plane_create_alpha_property);
+
+/**
  * drm_plane_create_rotation_property - create a new rotation property
  * @plane: drm plane
  * @rotation: initial value of the rotation property
diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h
index 17606026590b..5979a8fce453 100644
--- a/include/drm/drm_blend.h
+++ b/include/drm/drm_blend.h
@@ -36,6 +36,7 @@ static inline bool drm_rotation_90_or_270(unsigned int rotation)
 	return rotation & (DRM_MODE_ROTATE_90 | DRM_MODE_ROTATE_270);
 }
 
+int drm_plane_create_alpha_property(struct drm_plane *plane, u8 alpha);
 int drm_plane_create_rotation_property(struct drm_plane *plane,
 				       unsigned int rotation,
 				       unsigned int supported_rotations);
diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h
index 571615079230..a5e26064b132 100644
--- a/include/drm/drm_plane.h
+++ b/include/drm/drm_plane.h
@@ -42,6 +42,7 @@ struct drm_modeset_acquire_ctx;
  *	plane (in 16.16)
  * @src_w: width of visible portion of plane (in 16.16)
  * @src_h: height of visible portion of plane (in 16.16)
+ * @alpha: opacity of the plane
  * @rotation: rotation of the plane
  * @zpos: priority of the given plane on crtc (optional)
  *	Note that multiple active planes on the same crtc can have an identical
@@ -105,6 +106,9 @@ struct drm_plane_state {
 	uint32_t src_x, src_y;
 	uint32_t src_h, src_w;
 
+	/* Plane opacity */
+	u8 alpha;
+
 	/* Plane rotation */
 	unsigned int rotation;
 
@@ -481,6 +485,7 @@ enum drm_plane_type {
  * @funcs: helper functions
  * @properties: property tracking for this plane
  * @type: type of plane (overlay, primary, cursor)
+ * @alpha_property: alpha property for this plane
  * @zpos_property: zpos property for this plane
  * @rotation_property: rotation property for this plane
  * @helper_private: mid-layer private data
@@ -546,6 +551,7 @@ struct drm_plane {
 	 */
 	struct drm_plane_state *state;
 
+	struct drm_property *alpha_property;
 	struct drm_property *zpos_property;
 	struct drm_property *rotation_property;
 };
-- 
git-series 0.9.1