DaVinci does not support true I2S or right justified
mode so not all I2S codecs will work with it when the codec is
master. Document this limitation.
Signed-off-by: Troy Kisky <troy.kisky@xxxxxxxxxxxxxxxxxxx>
diff --git a/sound/soc/davinci/davinci-i2s.c b/sound/soc/davinci/davinci-i2s.c
index c425c86..735ec86 100644
--- a/sound/soc/davinci/davinci-i2s.c
+++ b/sound/soc/davinci/davinci-i2s.c
@@ -241,9 +241,26 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
rcr = DAVINCI_MCBSP_RCR_RFRLEN1(1);
xcr = DAVINCI_MCBSP_XCR_XFIG | DAVINCI_MCBSP_XCR_XFRLEN1(1);
switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
- case SND_SOC_DAIFMT_RIGHT_J:
+ case SND_SOC_DAIFMT_DSP_A:
break;
case SND_SOC_DAIFMT_I2S:
+ /* Davinci doesn't support TRUE I2S, but some codecs will have
+ * the left and right channels contiguous. This allows
+ * dsp_b mode to be used with an inverted normal frame clk.
+ * If your codec is master and does not have contiguous
+ * channels, then you will have sound on only one channel.
+ * Try using a different mode, or codec as slave.
+ *
+ * The TLV320AIC33 is an example of a codec where this works.
+ * It has a variable bit clock frequency allowing it to have
+ * valid data on every bit clock.
+ *
+ * The TLV320AIC23 is an example of a codec where this does not
+ * work. It has a fixed bit clock frequency with progressively
+ * more empty bit clock slots between channels as the sample
+ * rate is lowered.
+ */
+ fmt ^= SND_SOC_DAIFMT_NB_IF;
case SND_SOC_DAIFMT_DSP_B:
rcr |= DAVINCI_MCBSP_RCR_RDATDLY(1);
xcr |= DAVINCI_MCBSP_XCR_XDATDLY(1);
--
1.5.4.3
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