From: Matthias Reichl <hias@xxxxxxxxx>
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@xxxxxxxx>
Signed-off-by: Matthias Reichl <hias@xxxxxxxxx>
Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
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;
--
2.1.4
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