MQS: Play nice

keeps 352kHZ PWM, but reduces hardware-oversampling to 32x

output_mqs.cpp

@@ -196,12 +196,11 @@ void AudioOutputMQS::config_i2s(void)
 //TODO: Check if frequencies are correct!
 
 	int fs = AUDIO_SAMPLE_RATE_EXACT;
-	int oversample = 64*8;
 	// PLL between 27*24 = 648MHz und 54*24=1296MHz
 	int n1 = 4; //SAI prescaler 4 => (n1*n2) = multiple of 4
-	int n2 = 1 + (24000000 * 27) / (fs * oversample * n1);
+	int n2 = 1 + (24000000 * 27) / (fs * 256 * n1);
 
-	double C = ((double)fs * oversample * n1 * n2) / 24000000;
+	double C = ((double)fs * 256 * n1 * n2) / 24000000;
 	int c0 = C;
 	int c2 = 10000;
 	int c1 = C * c2 - (c0 * c2);
@@ -217,7 +216,7 @@ void AudioOutputMQS::config_i2s(void)
 			| (IOMUXC_GPR_GPR1_SAI3_MCLK_DIR | IOMUXC_GPR_GPR1_SAI3_MCLK3_SEL(0));	//Select MCLK
 
 	IOMUXC_GPR_GPR2 = (IOMUXC_GPR_GPR2 & ~(IOMUXC_GPR_GPR2_MQS_OVERSAMPLE | IOMUXC_GPR_GPR2_MQS_CLK_DIV_MASK))
-			| IOMUXC_GPR_GPR2_MQS_EN | IOMUXC_GPR_GPR2_MQS_OVERSAMPLE | IOMUXC_GPR_GPR2_MQS_CLK_DIV(0);
+			| IOMUXC_GPR_GPR2_MQS_EN /*| IOMUXC_GPR_GPR2_MQS_OVERSAMPLE */| IOMUXC_GPR_GPR2_MQS_CLK_DIV(0);
 
 	if (I2S3_TCSR & I2S_TCSR_TE) return;
 
@@ -225,7 +224,7 @@ void AudioOutputMQS::config_i2s(void)
 //	I2S3_TCSR = (1<<25); //Reset
 	I2S3_TCR1 = I2S_TCR1_RFW(1);
 	I2S3_TCR2 = I2S_TCR2_SYNC(0) /*| I2S_TCR2_BCP*/ // sync=0; tx is async;
-		    | (I2S_TCR2_BCD | I2S_TCR2_DIV((7)) | I2S_TCR2_MSEL(1));
+		    | (I2S_TCR2_BCD | I2S_TCR2_DIV((3)) | I2S_TCR2_MSEL(1));
 	I2S3_TCR3 = I2S_TCR3_TCE;
 	I2S3_TCR4 = I2S_TCR4_FRSZ((2-1)) | I2S_TCR4_SYWD((16-1)) | I2S_TCR4_MF | I2S_TCR4_FSD /*| I2S_TCR4_FSE*/ /* | I2S_TCR4_FSP */;
 	I2S3_TCR5 = I2S_TCR5_WNW((16-1)) | I2S_TCR5_W0W((16-1)) | I2S_TCR5_FBT((16-1));