ASoC: mxs-sgtl5000: Remove MCLK restriction

From: Fabio Estevam <[email protected]>

According to the sgtl5000 datasheet the MCLK frequency range restriction of 8 to 27 MHz only applies when the PLL is used - synchronous SYS_MCLK input mode.

mxs-sgtl5000 machine sets the codec as slave, and mx28 generates MCLK in the range of 256*fs, 384*fs or 512*fs, which is called asynchronous SYS_MCLK input.

In asynchronous SYS_MCLK we cannot have the 8 to 27 MHz check because if we want to play a 8KHz sample rate track, with a MCLK of 8k * 512 = 4.096MHz the current check would return -EINVAL, which is not correct.

Remove the 8 to 27MHz frequency check, since this only applies to the synchronous SYS_MCLK input case.

---
 sound/soc/mxs/mxs-sgtl5000.c | 7 -------
 1 file changed, 7 deletions(-)

index 7515cd4..6f1916b 100644
@@ -49,13 +49,6 @@ static int mxs_sgtl5000_hw_params(struct snd_pcm_substream *substream,
 		break;
 	}
 
-	/* Sgtl5000 sysclk should be >= 8MHz and <= 27M */
-	if (mclk < 8000000 || mclk > 27000000) {
-		dev_err(codec_dai->dev, "Invalid mclk frequency: %u.%03uMHz\n",
-			mclk / 1000000, mclk / 1000 % 1000);
-		return -EINVAL;
-	}
-
 	/* Set SGTL5000's SYSCLK (provided by SAIF MCLK) */
 	ret = snd_soc_dai_set_sysclk(codec_dai, SGTL5000_SYSCLK, mclk, 0);
 	if (ret) {

1.9.1

From: Fabio Estevam <[email protected]>

According to the sgtl5000 datasheet the MCLK frequency range restriction of 8 to 27 MHz only applies when the PLL is used - synchronous SYS_MCLK input mode.

When running the codec as slave, the master should generate MCLK in the range of 256*fs, 384*fs or 512*fs, which is called asynchronous SYS_MCLK input mode.

In asynchronous SYS_MCLK we cannot have the 8 to 27 MHz check because if we want to play a 8KHz sample rate track, with a MCLK of 8k * 512 = 4.096MHz the current check would return -EINVAL, which is not correct.

Remove the 8 to 27MHz frequency check, since this only applies to the synchronous SYS_MCLK input case.

---
 sound/soc/codecs/sgtl5000.c | 9 ---------
 1 file changed, 9 deletions(-)

index 600c072..8dea6b3 100644
@@ -1434,7 +1434,6 @@ static int sgtl5000_i2c_probe(struct i2c_client *client,
 {
 	struct sgtl5000_priv *sgtl5000;
 	int ret, reg, rev;
-	unsigned int mclk;
 	struct device_node *np = client->dev.of_node;
 	u32 value;
 

@@ -1459,14 +1458,6 @@ static int sgtl5000_i2c_probe(struct i2c_client *client,
 		return ret;
 	}
 
-	/* SGTL5000 SYS_MCLK should be between 8 and 27 MHz */
-	mclk = clk_get_rate(sgtl5000->mclk);
-	if (mclk < 8000000 || mclk > 27000000) {
-		dev_err(&client->dev, "Invalid SYS_CLK frequency: %u.%03uMHz\n",
-			mclk / 1000000, mclk / 1000 % 1000);
-		return -EINVAL;
-	}
-
 	ret = clk_prepare_enable(sgtl5000->mclk);
 	if (ret)
 		return ret;

1.9.1

From: Fabio Estevam <[email protected]>

When trying to play a 8kHz file with codec in slave mode we get the following error on a mx28evk:

$ aplay -Dhw:0,0 stereo_8k.wav 
Playing WAVE 'stereo_8k.wav' : Signed 16 bit Little Endian, Rate 8000 Hz, Stereo
[   21.218647] sgtl5000 0-000a: PLL not supported in slave mode
[   21.224559] sgtl5000 0-000a: 128 ratio is not supported. SYS_MCLK needs to be 256, 384 or 512 * fs
[   21.233687] sgtl5000 0-000a: ASoC: can't set sgtl5000 hw params: -22
aplay: set_params:1123: Unable to install hw params:

This error happens because we are using 'sys_fs' instead of 'frame_rate' in the valid ratio check.

Use the real'frame_rate' so that the ratio is correctly calculated and the playback can run.

sgtl5000 codec manual states that in 'Synchronous SYS_MCLK input' mode that the following SYS_CLK frequencies are allowed: 256*fs, 384*fs, 512*fs.

, where fs is the sampling frequency, which can be in the range of:
8, 11.025, 16, 22.5, 32, 44.1, 48, 96 kHz.

---
 sound/soc/codecs/sgtl5000.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 8dea6b3..29cf7ce 100644
@@ -618,7 +618,7 @@ static int sgtl5000_set_clock(struct snd_soc_codec *codec, int frame_rate)
 	 * factor of freq = 96 kHz can only be 256, since mclk is in the range
 	 * of 8 MHz - 27 MHz
 	 */
-	switch (sgtl5000->sysclk / sys_fs) {
+	switch (sgtl5000->sysclk / frame_rate) {
 	case 256:
 		clk_ctl |= SGTL5000_MCLK_FREQ_256FS <<
 			SGTL5000_MCLK_FREQ_SHIFT;

@@ -641,7 +641,7 @@ static int sgtl5000_set_clock(struct snd_soc_codec *codec, int frame_rate)
 				"PLL not supported in slave mode\n");
 			dev_err(codec->dev, "%d ratio is not supported. "
 				"SYS_MCLK needs to be 256, 384 or 512 * fs\n",
-				sgtl5000->sysclk / sys_fs);
+				sgtl5000->sysclk / frame_rate);
 			return -EINVAL;
 		}
 	}

1.9.1

Applied all, thanks.