[PATCH v3 weston 3/5] compositor-drm: add support for CTM property

[harsha.manjulamallikarjun at in.bosch.com]

From: Harsha M M <harsha.manjulamallikarjun at in.bosch.com>

Implement support for setting color transformation matrix
using drm CTM property.

Signed-off-by: Harsha M M <harsha.manjulamallikarjun at in.bosch.com>
---
 libweston/compositor-drm.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/libweston/compositor-drm.c b/libweston/compositor-drm.c
index 27c95da..7aa30a7 100644
--- a/libweston/compositor-drm.c
+++ b/libweston/compositor-drm.c
@@ -198,6 +198,7 @@ enum wdrm_crtc_property {
 	WDRM_CRTC_ACTIVE,
 	WDRM_CRTC_GAMMA_LUT,
 	WDRM_CRTC_GAMMA_LUT_SIZE,
+	WDRM_CRTC_CTM,
 	WDRM_CRTC__COUNT
 };
 
@@ -206,6 +207,7 @@ static const struct drm_property_info crtc_props[] = {
 	[WDRM_CRTC_ACTIVE] = { .name = "ACTIVE", },
 	[WDRM_CRTC_GAMMA_LUT] = { .name = "GAMMA_LUT", },
 	[WDRM_CRTC_GAMMA_LUT_SIZE] = { .name = "GAMMA_LUT_SIZE", },
+	[WDRM_CRTC_CTM] = { .name = "CTM", },
 };
 
 /**
@@ -1748,6 +1750,67 @@ drm_output_render(struct drm_output_state *state, pixman_region32_t *damage)
 				 &c->primary_plane.damage, damage);
 }
 
+static int64_t
+drm_convert_to_ctm_format(float coefficient)
+{
+	int64_t ret;
+	int64_t max_coefficient = (int64_t)(1ULL << 31);
+
+	/* convert float to S31.32 format as needed by drm_color_ctm
+	 *  matrix co-effecients*/
+	if (coefficient <= (float)-max_coefficient)
+		ret = (int64_t)(~0ULL);
+	else if (coefficient >= (float)max_coefficient)
+		ret = (int64_t)(~(1ULL << 63));
+	else if (coefficient < 0) {
+		ret = (int64_t)((-coefficient * ((int64_t) 1L << 32)) + 0.5);
+		ret |= 1ULL << 63;
+	} else
+		ret = (int64_t)((coefficient * ((int64_t) 1L << 32)) + 0.5);
+
+	return ret;
+}
+
+static void
+drm_output_set_ctm(struct weston_output *output_base,
+		   struct weston_matrix *ctm_matrix)
+{
+	struct drm_output *output = to_drm_output(output_base);
+	struct drm_backend *backend = to_drm_backend(output->base.compositor);
+	struct drm_color_ctm ctm;
+	uint32_t ctm_blobid = 0;
+	uint32_t ctm_prop_id;
+	int row;
+	int col;
+	int rc;
+	float coefficient;
+
+	ctm_prop_id = output->props_crtc[WDRM_CRTC_CTM].prop_id;
+	if (!ctm_prop_id)
+		return;
+
+	for (row = 0; row < 3; row++) {
+		for (col = 0; col < 3; col++) {
+			coefficient = ctm_matrix->d[(row * 4) + col];
+			ctm.matrix[(row * 3) +  col] =
+					drm_convert_to_ctm_format(coefficient);
+		}
+	}
+
+	rc = drmModeCreatePropertyBlob(backend->drm.fd, &ctm, sizeof(ctm),
+				       &ctm_blobid);
+	if (!rc) {
+		rc = drmModeObjectSetProperty(backend->drm.fd, output->crtc_id,
+					      DRM_MODE_OBJECT_CRTC, ctm_prop_id,
+					      ctm_blobid);
+		if (rc)
+			weston_log("failed to set ctm for crtc %d: %m\n",
+				   output->crtc_id);
+
+		drmModeDestroyPropertyBlob(backend->drm.fd, ctm_blobid);
+	}
+}
+
 static void
 drm_output_set_gamma(struct weston_output *output_base,
 		     uint16_t size, uint16_t *r, uint16_t *g, uint16_t *b)
@@ -5166,6 +5229,9 @@ drm_output_enable(struct weston_output *base)
 	output->base.set_dpms = drm_set_dpms;
 	output->base.switch_mode = drm_output_switch_mode;
 	output->base.set_gamma = drm_output_set_gamma;
+
+	if (output->props_crtc[WDRM_CRTC_CTM].prop_id)
+		output->base.set_ctm = drm_output_set_ctm;
 
 	if (output->cursor_plane)
 		weston_compositor_stack_plane(b->compositor,
-- 
2.7.4