drm/colorop: Add multiplier type

This introduces a new drm_colorop_type: DRM_COLOROP_MULTIPLIER.

It's a simple multiplier to all pixel values. The value is
specified via a S31.32 fixed point provided via the
"MULTIPLIER" property.

Reviewed-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: Sebastian Wick <sebastian.wick@redhat.com>
Signed-off-by: Simon Ser <contact@emersion.fr>
Link: https://patch.msgid.link/20251115000237.3561250-41-alex.hung@amd.com

Author: Alex Hung

drivers/gpu/drm/drm_atomic.c

@@ -801,6 +801,9 @@ static void drm_atomic_colorop_print_state(struct drm_printer *p,
 	case DRM_COLOROP_CTM_3X4:
 		drm_printf(p, "\tdata blob id=%d\n", state->data ? state->data->base.id : 0);
 		break;
+	case DRM_COLOROP_MULTIPLIER:
+		drm_printf(p, "\tmultiplier=%llu\n", state->multiplier);
+		break;
 	default:
 		break;
 	}

drivers/gpu/drm/drm_atomic_uapi.c

@@ -728,6 +728,8 @@ static int drm_atomic_colorop_set_property(struct drm_colorop *colorop,
 		state->bypass = val;
 	} else if (property == colorop->curve_1d_type_property) {
 		state->curve_1d_type = val;
+	} else if (property == colorop->multiplier_property) {
+		state->multiplier = val;
 	} else if (property == colorop->data_property) {
 		return drm_atomic_color_set_data_property(colorop, state,
 							  property, val);
@@ -753,6 +755,8 @@ drm_atomic_colorop_get_property(struct drm_colorop *colorop,
 		*val = state->bypass;
 	else if (property == colorop->curve_1d_type_property)
 		*val = state->curve_1d_type;
+	else if (property == colorop->multiplier_property)
+		*val = state->multiplier;
 	else if (property == colorop->size_property)
 		*val = colorop->size;
 	else if (property == colorop->data_property)

drivers/gpu/drm/drm_colorop.c

@@ -66,6 +66,7 @@ static const struct drm_prop_enum_list drm_colorop_type_enum_list[] = {
 	{ DRM_COLOROP_1D_CURVE, "1D Curve" },
 	{ DRM_COLOROP_1D_LUT, "1D LUT" },
 	{ DRM_COLOROP_CTM_3X4, "3x4 Matrix"},
+	{ DRM_COLOROP_MULTIPLIER, "Multiplier"},
 };
 
 static const char * const colorop_curve_1d_type_names[] = {
@@ -325,6 +326,37 @@ int drm_plane_colorop_ctm_3x4_init(struct drm_device *dev, struct drm_colorop *c
 }
 EXPORT_SYMBOL(drm_plane_colorop_ctm_3x4_init);
 
+/**
+ * drm_plane_colorop_mult_init - Initialize a DRM_COLOROP_MULTIPLIER
+ *
+ * @dev: DRM device
+ * @colorop: The drm_colorop object to initialize
+ * @plane: The associated drm_plane
+ * @return zero on success, -E value on failure
+ */
+int drm_plane_colorop_mult_init(struct drm_device *dev, struct drm_colorop *colorop,
+				struct drm_plane *plane)
+{
+	struct drm_property *prop;
+	int ret;
+
+	ret = drm_plane_colorop_init(dev, colorop, plane, DRM_COLOROP_MULTIPLIER);
+	if (ret)
+		return ret;
+
+	prop = drm_property_create_range(dev, DRM_MODE_PROP_ATOMIC, "MULTIPLIER", 0, U64_MAX);
+	if (!prop)
+		return -ENOMEM;
+
+	colorop->multiplier_property = prop;
+	drm_object_attach_property(&colorop->base, colorop->multiplier_property, 0);
+
+	drm_colorop_reset(colorop);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_plane_colorop_mult_init);
+
 static void __drm_atomic_helper_colorop_duplicate_state(struct drm_colorop *colorop,
 							struct drm_colorop_state *state)
 {
@@ -415,6 +447,7 @@ static const char * const colorop_type_name[] = {
 	[DRM_COLOROP_1D_CURVE] = "1D Curve",
 	[DRM_COLOROP_1D_LUT] = "1D LUT",
 	[DRM_COLOROP_CTM_3X4] = "3x4 Matrix",
+	[DRM_COLOROP_MULTIPLIER] = "Multiplier",
 };
 
 const char *drm_get_colorop_type_name(enum drm_colorop_type type)

include/drm/drm_colorop.h

@@ -144,6 +144,13 @@ struct drm_colorop_state {
 	 */
 	enum drm_colorop_curve_1d_type curve_1d_type;
 
+	/**
+	 * @multiplier:
+	 *
+	 * Multiplier to 'gain' the plane. Format is S31.32 sign-magnitude.
+	 */
+	uint64_t multiplier;
+
 	/**
 	 * @data:
 	 *
@@ -271,6 +278,13 @@ struct drm_colorop {
 	 */
 	struct drm_property *curve_1d_type_property;
 
+	/**
+	 * @multiplier_property:
+	 *
+	 * Multiplier property for plane gain
+	 */
+	struct drm_property *multiplier_property;
+
 	/**
 	 * @size_property:
 	 *
@@ -329,6 +343,8 @@ int drm_plane_colorop_curve_1d_lut_init(struct drm_device *dev, struct drm_color
 					struct drm_plane *plane, uint32_t lut_size);
 int drm_plane_colorop_ctm_3x4_init(struct drm_device *dev, struct drm_colorop *colorop,
 				   struct drm_plane *plane);
+int drm_plane_colorop_mult_init(struct drm_device *dev, struct drm_colorop *colorop,
+				struct drm_plane *plane);
 
 struct drm_colorop_state *
 drm_atomic_helper_colorop_duplicate_state(struct drm_colorop *colorop);

include/uapi/drm/drm_mode.h

@@ -931,6 +931,17 @@ enum drm_colorop_type {
 	 * | B |   | 8  9  10 12 |   | B |
 	 */
 	DRM_COLOROP_CTM_3X4,
+
+	/**
+	 * @DRM_COLOROP_MULTIPLIER:
+	 *
+	 * enum string "Multiplier"
+	 *
+	 * A simple multiplier, applied to all color values. The
+	 * multiplier is specified as a S31.32 via the MULTIPLIER
+	 * property.
+	 */
+	DRM_COLOROP_MULTIPLIER,
 };
 
 /**