[PATCH] drm/meson: plane: add pixel blend mode property

[Jose Nieto]

The primary plane exposes ARGB8888, a format with alpha, but never set up
the pixel blend mode property. This makes the DRM core warn at boot:

  [PLANE:...:meson_primary_plane] pixel format with alpha exposed but
  blend mode not setup. Please fix.

Advertise PIXEL_NONE and COVERAGE and derive OSD_REPLACE_EN from the
requested blend mode. Formats without alpha (e.g. XRGB8888) keep the
previous opaque behaviour.

Signed-off-by: Jose Nieto <jnieto.alaber at gmail.com>
---
 drivers/gpu/drm/meson/meson_plane.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/meson/meson_plane.c b/drivers/gpu/drm/meson/meson_plane.c
index cf8c90158fcf..115849a0b0c8 100644
--- a/drivers/gpu/drm/meson/meson_plane.c
+++ b/drivers/gpu/drm/meson/meson_plane.c
@@ -233,18 +233,13 @@ static void meson_plane_atomic_update(struct drm_plane *plane,
 		}
 	}
 
-	switch (fb->format->format) {
-	case DRM_FORMAT_XRGB8888:
-	case DRM_FORMAT_XBGR8888:
-		/* For XRGB, replace the pixel's alpha by 0xFF */
+	if (!fb->format->has_alpha ||
+	    new_state->pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE)
+		/* Ignore the pixel's alpha */
 		priv->viu.osd1_ctrl_stat2 |= OSD_REPLACE_EN;
-		break;
-	case DRM_FORMAT_ARGB8888:
-	case DRM_FORMAT_ABGR8888:
-		/* For ARGB, use the pixel's alpha */
+	else
+		/* Use the pixel's alpha */
 		priv->viu.osd1_ctrl_stat2 &= ~OSD_REPLACE_EN;
-		break;
-	}
 
 	/* Default scaler parameters */
 	vsc_bot_rcv_num = 0;
@@ -536,6 +531,7 @@ int meson_plane_create(struct meson_drm *priv)
 	struct drm_plane *plane;
 	const uint64_t *format_modifiers = format_modifiers_default;
 	int ret;
+	unsigned int blend_modes = BIT(DRM_MODE_BLEND_PIXEL_NONE) | BIT(DRM_MODE_BLEND_COVERAGE);
 
 	meson_plane = devm_kzalloc(priv->drm->dev, sizeof(*meson_plane),
 				   GFP_KERNEL);
@@ -566,6 +562,10 @@ int meson_plane_create(struct meson_drm *priv)
 	/* For now, OSD Primary plane is always on the front */
 	drm_plane_create_zpos_immutable_property(plane, 1);
 
+	ret = drm_plane_create_blend_mode_property(plane, blend_modes);
+	if (ret)
+		return ret;
+
 	priv->primary_plane = plane;
 
 	return 0;
-- 
2.47.3