[PATCH 13/18] drm/vc4: hdmi: Define colorspace matrices

[Maxime Ripard]

The current CSC setup code for the BCM2711 uses a sequence of register
writes to configure the CSC depending on whether we output using a full
or limited range.

However, with the upcoming introduction of the YUV output, we're going
to add new matrices to perform the conversions, so we should switch to
something a bit more flexible that takes the matrix as an argument and
programs the CSC accordingly.

Signed-off-by: Maxime Ripard <maxime at cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 77 +++++++++++++++++++++-------------
 1 file changed, 48 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index b0e0cb533944..9614de7303b8 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -525,6 +525,50 @@ static void vc4_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
 	HDMI_WRITE(HDMI_CSC_CTL, csc_ctl);
 }
 
+
+/*
+ * If we need to output Full Range RGB, then use the unity matrix
+ *
+ * [ 1      0      0      0]
+ * [ 0      1      0      0]
+ * [ 0      0      1      0]
+ *
+ * Matrix is signed 2p13 fixed point, with signed 9p6 offsets
+ */
+static const u16 vc5_hdmi_csc_full_rgb_unity[3][4] = {
+	{ 0x2000, 0x0000, 0x0000, 0x0000 },
+	{ 0x0000, 0x2000, 0x0000, 0x0000 },
+	{ 0x0000, 0x0000, 0x2000, 0x0000 },
+};
+
+/*
+ * CEA VICs other than #1 require limited range RGB output unless
+ * overridden by an AVI infoframe. Apply a colorspace conversion to
+ * squash 0-255 down to 16-235. The matrix here is:
+ *
+ * [ 0.8594 0      0      16]
+ * [ 0      0.8594 0      16]
+ * [ 0      0      0.8594 16]
+ *
+ * Matrix is signed 2p13 fixed point, with signed 9p6 offsets
+ */
+static const u16 vc5_hdmi_csc_full_rgb_to_limited_rgb[3][4] = {
+	{ 0x1b80, 0x0000, 0x0000, 0x0400 },
+	{ 0x0000, 0x1b80, 0x0000, 0x0400 },
+	{ 0x0000, 0x0000, 0x1b80, 0x0400 },
+};
+
+static void vc5_hdmi_set_csc_coeffs(struct vc4_hdmi *vc4_hdmi,
+				    const u16 coeffs[3][4])
+{
+	HDMI_WRITE(HDMI_CSC_12_11, (coeffs[0][1] << 16) | coeffs[0][0]);
+	HDMI_WRITE(HDMI_CSC_14_13, (coeffs[0][3] << 16) | coeffs[0][2]);
+	HDMI_WRITE(HDMI_CSC_22_21, (coeffs[1][1] << 16) | coeffs[1][0]);
+	HDMI_WRITE(HDMI_CSC_24_23, (coeffs[1][3] << 16) | coeffs[1][2]);
+	HDMI_WRITE(HDMI_CSC_32_31, (coeffs[2][1] << 16) | coeffs[2][0]);
+	HDMI_WRITE(HDMI_CSC_34_33, (coeffs[2][3] << 16) | coeffs[2][2]);
+}
+
 static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
 			       const struct drm_display_mode *mode)
 {
@@ -533,35 +577,10 @@ static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
 
 	HDMI_WRITE(HDMI_VEC_INTERFACE_XBAR, 0x354021);
 
-	if (vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode)) {
-		/* CEA VICs other than #1 requre limited range RGB
-		 * output unless overridden by an AVI infoframe.
-		 * Apply a colorspace conversion to squash 0-255 down
-		 * to 16-235.  The matrix here is:
-		 *
-		 * [ 0.8594 0      0      16]
-		 * [ 0      0.8594 0      16]
-		 * [ 0      0      0.8594 16]
-		 * [ 0      0      0       1]
-		 * Matrix is signed 2p13 fixed point, with signed 9p6 offsets
-		 */
-		HDMI_WRITE(HDMI_CSC_12_11, (0x0000 << 16) | 0x1b80);
-		HDMI_WRITE(HDMI_CSC_14_13, (0x0400 << 16) | 0x0000);
-		HDMI_WRITE(HDMI_CSC_22_21, (0x1b80 << 16) | 0x0000);
-		HDMI_WRITE(HDMI_CSC_24_23, (0x0400 << 16) | 0x0000);
-		HDMI_WRITE(HDMI_CSC_32_31, (0x0000 << 16) | 0x0000);
-		HDMI_WRITE(HDMI_CSC_34_33, (0x0400 << 16) | 0x1b80);
-	} else {
-		/* Still use the matrix for full range, but make it unity.
-		 * Matrix is signed 2p13 fixed point, with signed 9p6 offsets
-		 */
-		HDMI_WRITE(HDMI_CSC_12_11, (0x0000 << 16) | 0x2000);
-		HDMI_WRITE(HDMI_CSC_14_13, (0x0000 << 16) | 0x0000);
-		HDMI_WRITE(HDMI_CSC_22_21, (0x2000 << 16) | 0x0000);
-		HDMI_WRITE(HDMI_CSC_24_23, (0x0000 << 16) | 0x0000);
-		HDMI_WRITE(HDMI_CSC_32_31, (0x0000 << 16) | 0x0000);
-		HDMI_WRITE(HDMI_CSC_34_33, (0x0000 << 16) | 0x2000);
-	}
+	if (vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode))
+		vc5_hdmi_set_csc_coeffs(vc4_hdmi, &vc5_hdmi_csc_full_rgb_unity);
+	else
+		vc5_hdmi_set_csc_coeffs(vc4_hdmi, &vc5_hdmi_csc_full_rgb_to_limited_rgb);
 
 	HDMI_WRITE(HDMI_CSC_CTL, csc_ctl);
 }
-- 
2.30.2