OMAPDSS: HDMI: Add support for more audio sample rates in N/CTS calcu…

…lation Add support for more sample rates when calculating N and CTS. This covers all the audio sample rates that an HDMI source is allowed to transmit according to the HDMI 1.4a specification. Also, reorganize the logic for the calculation when using deep color. Signed-off-by: Ricardo Neri <[email protected]>
syzer · May 11, 2012 · 25a6535 · 25a6535
1 parent 3554762
commit 25a6535
Showing 1 changed file with 74 additions and 14 deletions.
diff --git a/drivers/video/omap2/dss/hdmi.c b/drivers/video/omap2/dss/hdmi.c
@@ -558,6 +558,7 @@ static void hdmi_put_clocks(void)
 int hdmi_compute_acr(u32 sample_freq, u32 *n, u32 *cts)
 {
 	u32 deep_color;
+	bool deep_color_correct = false;
 	u32 pclk = hdmi.ip_data.cfg.timings.pixel_clock;
 
 	if (n == NULL || cts == NULL)
@@ -566,29 +567,88 @@ int hdmi_compute_acr(u32 sample_freq, u32 *n, u32 *cts)
 	/* TODO: When implemented, query deep color mode here. */
 	deep_color = 100;
 
+	/*
+	 * When using deep color, the default N value (as in the HDMI
+	 * specification) yields to an non-integer CTS. Hence, we
+	 * modify it while keeping the restrictions described in
+	 * section 7.2.1 of the HDMI 1.4a specification.
+	 */
 	switch (sample_freq) {
 	case 32000:
-		if ((deep_color == 125) && ((pclk == 54054) ||
-					    (pclk == 74250)))
-			*n = 8192;
-		else
-			*n = 4096;
+	case 48000:
+	case 96000:
+	case 192000:
+		if (deep_color == 125)
+			if (pclk == 27027 || pclk == 74250)
+				deep_color_correct = true;
+		if (deep_color == 150)
+			if (pclk == 27027)
+				deep_color_correct = true;
 		break;
 	case 44100:
-		*n = 6272;
-		break;
-	case 48000:
-		if ((deep_color == 125) && ((pclk == 54054) ||
-					    (pclk == 74250)))
-			*n = 8192;
-		else
-			*n = 6144;
+	case 88200:
+	case 176400:
+		if (deep_color == 125)
+			if (pclk == 27027)
+				deep_color_correct = true;
 		break;
 	default:
-		*n = 0;
 		return -EINVAL;
 	}
 
+	if (deep_color_correct) {
+		switch (sample_freq) {
+		case 32000:
+			*n = 8192;
+			break;
+		case 44100:
+			*n = 12544;
+			break;
+		case 48000:
+			*n = 8192;
+			break;
+		case 88200:
+			*n = 25088;
+			break;
+		case 96000:
+			*n = 16384;
+			break;
+		case 176400:
+			*n = 50176;
+			break;
+		case 192000:
+			*n = 32768;
+			break;
+		default:
+			return -EINVAL;
+		}
+	} else {
+		switch (sample_freq) {
+		case 32000:
+			*n = 4096;
+			break;
+		case 44100:
+			*n = 6272;
+			break;
+		case 48000:
+			*n = 6144;
+			break;
+		case 88200:
+			*n = 12544;
+			break;
+		case 96000:
+			*n = 12288;
+			break;
+		case 176400:
+			*n = 25088;
+			break;
+		case 192000:
+			*n = 24576;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
 	/* Calculate CTS. See HDMI 1.3a or 1.4a specifications */
 	*cts = pclk * (*n / 128) * deep_color / (sample_freq / 10);