ALSA: add DSD formats

This patch adds two formats for Direct Stream Digital (DSD), a
pulse-density encoding format which is described here:
https://en.wikipedia.org/wiki/Direct_Stream_Digital

DSD operates on 2.8, 5.6 or 11.2MHz sample rates and as a 1-bit
stream.

The two new types added by this patch describe streams that are capable
of handling DSD samples in DOP format as 8-bit or in 16-bit (or at a x8
or x16 data rate, respectively).

DSD itself specifies samples in *bit*, while DOP and ALSA handle them
as *bytes*. Hence, a factor of 8 or 16 has to be applied for the sample
rare configuration, according to the following table:

                                                  configured hardware
        176.4KHz   352.8kHz   705.6KHz     <----       sample rate

8-bit                2.8MHz     5.6MHz
16-bit    2.8Mhz     5.6MHz    11.2MHz

         `-----------------------------'
             actual DSD sample rates

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

2 files changed, 10 insertions, 0 deletions

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index 578327e2bc26..17f45e8aa89c 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -209,6 +209,8 @@ static char *snd_pcm_format_names[] = {
         FORMAT(G723_24_1B),
         FORMAT(G723_40),
         FORMAT(G723_40_1B),
+        FORMAT(DSD_U8),
+        FORMAT(DSD_U16_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 b875b19f2d55..43f24cce3dec 100644
--- a/sound/core/pcm_misc.c
+++ b/sound/core/pcm_misc.c
@@ -140,6 +140,14 @@ static struct pcm_format_data pcm_formats[(INT)SNDRV_PCM_FORMAT_LAST+1] = {
                 .width = 5, .phys = 5, .le = -1, .signd = -1,
                 .silence = {},
         },
+        [SNDRV_PCM_FORMAT_DSD_U8] = {
+                .width = 8, .phys = 8, .le = 1, .signd = 0,
+                .silence = {},
+        },
+        [SNDRV_PCM_FORMAT_DSD_U16_LE] = {
+                .width = 16, .phys = 16, .le = 1, .signd = 0,
+                .silence = {},
+        },
         /* FIXME: the following three formats are not defined properly yet */
         [SNDRV_PCM_FORMAT_MPEG] = {
                 .le = -1, .signd = -1,