[alsa-devel] [PATCH] ASoC: zx-i2s: fix harsh noise with 16-bit audio

[Shawn Guo]

From: Shawn Guo <shawn.guo at linaro.org>

The audio parameter setup in zx_i2s_hw_params() works fine with 32-bit
samples, but for 16-bit ones, all we can hear is harsh noises.
As suggested by vendor driver code, DMA burst size and TS width should
always be 32 bits, no matter audio sample is 16-bit or 32-bit.

Follow the suggestion above to fix the harsh noise issue seen with
16-bit audio samples.

Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
---
 sound/soc/zte/zx-i2s.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sound/soc/zte/zx-i2s.c b/sound/soc/zte/zx-i2s.c
index a865f37c2a56..a7f7a56e0a2d 100644
--- a/sound/soc/zte/zx-i2s.c
+++ b/sound/soc/zte/zx-i2s.c
@@ -226,11 +226,12 @@ static int zx_i2s_hw_params(struct snd_pcm_substream *substream,
 	struct zx_i2s_info *i2s = snd_soc_dai_get_drvdata(socdai);
 	struct snd_dmaengine_dai_dma_data *dma_data;
 	unsigned int lane, ch_num, len, ret = 0;
+	unsigned int ts_width = 32;
 	unsigned long val;
 	unsigned long chn_cfg;
 
 	dma_data = snd_soc_dai_get_dma_data(socdai, substream);
-	dma_data->addr_width = params_width(params) >> 3;
+	dma_data->addr_width = ts_width >> 3;
 
 	val = readl_relaxed(i2s->reg_base + ZX_I2S_TIMING_CTRL);
 	val &= ~(ZX_I2S_TIMING_TS_WIDTH_MASK | ZX_I2S_TIMING_DATA_SIZE_MASK |
@@ -251,7 +252,7 @@ static int zx_i2s_hw_params(struct snd_pcm_substream *substream,
 		dev_err(socdai->dev, "Unknown data format\n");
 		return -EINVAL;
 	}
-	val |= ZX_I2S_TIMING_TS_WIDTH(len) | ZX_I2S_TIMING_DATA_SIZE(len);
+	val |= ZX_I2S_TIMING_TS_WIDTH(ts_width) | ZX_I2S_TIMING_DATA_SIZE(len);
 
 	ch_num = params_channels(params);
 	switch (ch_num) {
-- 
1.9.1