drm/vc4: hdmi: Define colorspace matrices

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.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220120151625.594595-10-maxime@cerno.tech

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -775,6 +775,51 @@ static void vc4_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
 	spin_unlock_irqrestore(&vc4_hdmi->hw_lock, flags);
 }
 
+/*
+ * 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])
+{
+	lockdep_assert_held(&vc4_hdmi->hw_lock);
+
+	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)
 {
@@ -786,35 +831,10 @@ 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_to_limited_rgb);
+	else
+		vc5_hdmi_set_csc_coeffs(vc4_hdmi, vc5_hdmi_csc_full_rgb_unity);
 
 	HDMI_WRITE(HDMI_CSC_CTL, csc_ctl);