[alsa-devel] [PATCH 1/5] ASoC: samsung: odroid: Fix 32000 sample rate handling

[Sylwester Nawrocki]

In case of sample rates lower than 44100 currently there is too low MCLK
frequency set for the CODEC. Playback fails with following errors:

$ speaker-test -c2 -t sine -f 1500 -l2 -r 32000

Sine wave rate is 1500.0000Hz
Rate set to 32000Hz (requested 32000Hz)
Buffer size range from 128 to 131072
Period size range from 64 to 65536
Using max buffer size 131072
Periods = 4
Unable to set hw params for playback: Invalid argument
Setting of hwparams failed: Invalid argument

[  497.883700] max98090 1-0010: Invalid master clock frequency

To fix this the I2S root clock's frequency is increased, depending
on sampling rate.

Signed-off-by: Sylwester Nawrocki <s.nawrocki at samsung.com>
---
 sound/soc/samsung/odroid.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/sound/soc/samsung/odroid.c b/sound/soc/samsung/odroid.c
index 92d750806d1d..e698e67f5f84 100644
--- a/sound/soc/samsung/odroid.c
+++ b/sound/soc/samsung/odroid.c
@@ -36,23 +36,26 @@ static int odroid_card_hw_params(struct snd_pcm_substream *substream,
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct odroid_priv *priv = snd_soc_card_get_drvdata(rtd->card);
-	unsigned int pll_freq, rclk_freq;
+	unsigned int pll_freq, rclk_freq, rfs;
 	int ret;
 
 	switch (params_rate(params)) {
-	case 32000:
 	case 64000:
-		pll_freq = 131072006U;
+		pll_freq = 196608001U;
+		rfs = 384;
 		break;
 	case 44100:
 	case 88200:
 	case 176400:
 		pll_freq = 180633609U;
+		rfs = 512;
 		break;
+	case 32000:
 	case 48000:
 	case 96000:
 	case 192000:
 		pll_freq = 196608001U;
+		rfs = 512;
 		break;
 	default:
 		return -EINVAL;
@@ -67,7 +70,7 @@ static int odroid_card_hw_params(struct snd_pcm_substream *substream,
 	 *  frequency values due to the EPLL output frequency not being exact
 	 *  multiple of the audio sampling rate.
 	 */
-	rclk_freq = params_rate(params) * 256 + 1;
+	rclk_freq = params_rate(params) * rfs + 1;
 
 	ret = clk_set_rate(priv->sclk_i2s, rclk_freq);
 	if (ret < 0)
-- 
2.14.2