From: Matthias Reichl hias@horus.com
Register as a custom pcm device with the correct settings supporting also 16 bit.
The automatic pcm discovery does not enable 16 bit modes because of a percived mismatch between the dma controller only supporting 32 bit transfers and the requirement by the HW to only support exactly 2 channels, which effectively results in a minimum size of 32 bits, which matches the dma controller transfer width.
Code ported from bcm2708-i2s driver in Raspberry Pi tree.
Signed-off-by: Florian Meier florian.meier@koalo.de Signed-off-by: Matthias Reichl hias@horus.com Signed-off-by: Martin Sperl kernel@martin.sperl.org
Changelog: V1 -> V2: use of SZ_* defines instead of multiple of page size better description of commit message --- sound/soc/bcm/bcm2835-i2s.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/sound/soc/bcm/bcm2835-i2s.c b/sound/soc/bcm/bcm2835-i2s.c index a0026e2..66680f1 100644 --- a/sound/soc/bcm/bcm2835-i2s.c +++ b/sound/soc/bcm/bcm2835-i2s.c @@ -632,6 +632,27 @@ static const struct snd_soc_component_driver bcm2835_i2s_component = { .name = "bcm2835-i2s-comp", };
+static const struct snd_pcm_hardware bcm2835_pcm_hardware = { + .info = SNDRV_PCM_INFO_INTERLEAVED | + SNDRV_PCM_INFO_JOINT_DUPLEX | + SNDRV_PCM_INFO_MMAP | + SNDRV_PCM_INFO_MMAP_VALID, + .formats = SNDRV_PCM_FMTBIT_S16_LE | + SNDRV_PCM_FMTBIT_S24_LE | + SNDRV_PCM_FMTBIT_S32_LE, + .period_bytes_min = 32, + .period_bytes_max = SZ_256K, + .periods_min = 2, + .periods_max = 255, + .buffer_bytes_max = SZ_512K, +}; + +static const struct snd_dmaengine_pcm_config bcm2835_dmaengine_pcm_config = { + .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config, + .pcm_hardware = &bcm2835_pcm_hardware, + .prealloc_buffer_size = SZ_1M, +}; + static int bcm2835_i2s_probe(struct platform_device *pdev) { struct bcm2835_i2s_dev *dev; @@ -704,7 +725,9 @@ static int bcm2835_i2s_probe(struct platform_device *pdev) return ret; }
- ret = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0); + ret = devm_snd_dmaengine_pcm_register( + &pdev->dev, &bcm2835_dmaengine_pcm_config, + SND_DMAENGINE_PCM_FLAG_COMPAT); if (ret) { dev_err(&pdev->dev, "Could not register PCM: %d\n", ret); return ret;