XMOS based USB DACs with native DSD support expose this feature via a USB alternate setting. The audio format is either 32-bit raw or a 32-bit PCM format. To utilize this feature on linux this patch introduces a new 32-bit DSD sampleformat DSD_U32_LE. A follow up patch will add a quirk for XMOS based devices to utilize the new format. Further patches will add support to alsa-lib.

Signed-off-by: Jurgen Kramer gtmkramer@xs4all.nl --- include/sound/pcm.h | 1 + include/uapi/sound/asound.h | 3 ++- sound/core/pcm.c | 1 + sound/core/pcm_misc.c | 4 ++++ 4 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/sound/pcm.h b/include/sound/pcm.h index 6f3e10c..faefd83 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -183,6 +183,7 @@ struct snd_pcm_ops { #define SNDRV_PCM_FMTBIT_G723_40_1B _SNDRV_PCM_FMTBIT(G723_40_1B) #define SNDRV_PCM_FMTBIT_DSD_U8 _SNDRV_PCM_FMTBIT(DSD_U8) #define SNDRV_PCM_FMTBIT_DSD_U16_LE _SNDRV_PCM_FMTBIT(DSD_U16_LE) +#define SNDRV_PCM_FMTBIT_DSD_U32_LE _SNDRV_PCM_FMTBIT(DSD_U32_LE)

#ifdef SNDRV_LITTLE_ENDIAN #define SNDRV_PCM_FMTBIT_S16 SNDRV_PCM_FMTBIT_S16_LE diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index 32168f7..6ee5867 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -219,7 +219,8 @@ typedef int __bitwise snd_pcm_format_t; #define SNDRV_PCM_FORMAT_G723_40_1B ((__force snd_pcm_format_t) 47) /* 1 sample in 1 byte */ #define SNDRV_PCM_FORMAT_DSD_U8 ((__force snd_pcm_format_t) 48) /* DSD, 1-byte samples DSD (x8) */ #define SNDRV_PCM_FORMAT_DSD_U16_LE ((__force snd_pcm_format_t) 49) /* DSD, 2-byte samples DSD (x16), little endian */ -#define SNDRV_PCM_FORMAT_LAST SNDRV_PCM_FORMAT_DSD_U16_LE +#define SNDRV_PCM_FORMAT_DSD_U32_LE ((__force snd_pcm_format_t) 50) /* DSD, 4-byte samples DSD (x32), little endian */ +#define SNDRV_PCM_FORMAT_LAST SNDRV_PCM_FORMAT_DSD_U32_LE

#ifdef SNDRV_LITTLE_ENDIAN #define SNDRV_PCM_FORMAT_S16 SNDRV_PCM_FORMAT_S16_LE diff --git a/sound/core/pcm.c b/sound/core/pcm.c index 43932e8..72eb20a 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -215,6 +215,7 @@ static char *snd_pcm_format_names[] = { FORMAT(G723_40_1B), FORMAT(DSD_U8), FORMAT(DSD_U16_LE), + FORMAT(DSD_U32_LE), };

const char *snd_pcm_format_name(snd_pcm_format_t format) diff --git a/sound/core/pcm_misc.c b/sound/core/pcm_misc.c index 2c6fd80..ae7a0fe 100644 --- a/sound/core/pcm_misc.c +++ b/sound/core/pcm_misc.c @@ -148,6 +148,10 @@ static struct pcm_format_data pcm_formats[(INT)SNDRV_PCM_FORMAT_LAST+1] = { .width = 16, .phys = 16, .le = 1, .signd = 0, .silence = { 0x69, 0x69 }, }, + [SNDRV_PCM_FORMAT_DSD_U32_LE] = { + .width = 32, .phys = 32, .le = 1, .signd = 0, + .silence = { 0x69, 0x69, 0x69, 0x69 }, + }, /* FIXME: the following three formats are not defined properly yet */ [SNDRV_PCM_FORMAT_MPEG] = { .le = -1, .signd = -1,