The bcm2835-i2s driver already has support for the S16_LE format but that format hasn't been made available because dmaengine_pcm didn't support packed data transfers.
bcm2835-i2s needs 16-bit left+right channel data to be packed into a 32-bit word, the FIFO register is 32-bit only and doesn't support 16-bit access.
Now that dmaengine_pcm supports packed transfers the format can be made available by setting the SND_DMAENGINE_PCM_DAI_FLAG_PACK flag.
No further configuration is necessary: - snd_dmaengine_dai_dma_data.addr_width is already set to DMA_SLAVE_BUSWIDTH_4_BYTES to force 32-bit DMA transfers - dmaengine_pcm will pick up the S16_LE format from the DAI configuration and make it available since it's no longer masked out due to the PACK flag. - there are no further corner cases to catch in hw_params, since the channel count is fixed at 2 we always have two 16-bit stereo samples that can be transferred via 32-bit DMA
Signed-off-by: Matthias Reichl hias@horus.com --- sound/soc/bcm/bcm2835-i2s.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/sound/soc/bcm/bcm2835-i2s.c b/sound/soc/bcm/bcm2835-i2s.c index 1c1f221..40ba01d 100644 --- a/sound/soc/bcm/bcm2835-i2s.c +++ b/sound/soc/bcm/bcm2835-i2s.c @@ -678,6 +678,15 @@ static int bcm2835_i2s_probe(struct platform_device *pdev) dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].maxburst = 2; dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].maxburst = 2;
+ /* + * Set the PACK flag to enable S16_LE support (2 S16_LE values + * packed into 32-bit transfers). + */ + dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].flags = + SND_DMAENGINE_PCM_DAI_FLAG_PACK; + dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].flags = + SND_DMAENGINE_PCM_DAI_FLAG_PACK; + /* BCLK ratio - use default */ dev->bclk_ratio = 0;