[PATCH v4 1/2] ALSA: pcm: add SNDRV_PCM_FORMAT_{S,U}20

From: Maciej S. Szmigiero
Date: Mon Nov 27 2017 - 17:33:41 EST

This format is similar to existing SNDRV_PCM_FORMAT_{S,U}20_3 that keep
20-bit PCM samples in 3 bytes, however i.MX6 platform SSI FIFO does not
allow 3-byte accesses (including DMA) so a 4-byte (more conventional)
format is needed for it.

Signed-off-by: Maciej S. Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx>
---
Changes from v1: Drop "_4" suffix from these formats since they aren't
non-standard ones, use empty format slots starting from format number 25
for them, add information that they are LSB justified formats.

Changes from v2: Adapt a comment in sound/core/pcm_misc.c so it still
refers to the same sample formats as before.

Changes from v3: Make the comment style in include/uapi/sound/asound.h
match the style of comments at other sample formats.

Corresponding alsa-lib changes will be posted as soon as this patch is
merged on the kernel side, to keep alsa-lib and kernel synchronized.

include/sound/pcm.h | 8 ++++++++
include/sound/soc-dai.h | 2 ++
include/uapi/sound/asound.h | 9 +++++++++
sound/core/pcm_misc.c | 19 ++++++++++++++++++-
4 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 24febf9e177c..e054c583d3b3 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -169,6 +169,10 @@ struct snd_pcm_ops {
#define SNDRV_PCM_FMTBIT_IMA_ADPCM _SNDRV_PCM_FMTBIT(IMA_ADPCM)
#define SNDRV_PCM_FMTBIT_MPEG _SNDRV_PCM_FMTBIT(MPEG)
#define SNDRV_PCM_FMTBIT_GSM _SNDRV_PCM_FMTBIT(GSM)
+#define SNDRV_PCM_FMTBIT_S20_LE _SNDRV_PCM_FMTBIT(S20_LE)
+#define SNDRV_PCM_FMTBIT_U20_LE _SNDRV_PCM_FMTBIT(U20_LE)
+#define SNDRV_PCM_FMTBIT_S20_BE _SNDRV_PCM_FMTBIT(S20_BE)
+#define SNDRV_PCM_FMTBIT_U20_BE _SNDRV_PCM_FMTBIT(U20_BE)
#define SNDRV_PCM_FMTBIT_SPECIAL _SNDRV_PCM_FMTBIT(SPECIAL)
#define SNDRV_PCM_FMTBIT_S24_3LE _SNDRV_PCM_FMTBIT(S24_3LE)
#define SNDRV_PCM_FMTBIT_U24_3LE _SNDRV_PCM_FMTBIT(U24_3LE)
@@ -202,6 +206,8 @@ struct snd_pcm_ops {
#define SNDRV_PCM_FMTBIT_FLOAT SNDRV_PCM_FMTBIT_FLOAT_LE
#define SNDRV_PCM_FMTBIT_FLOAT64 SNDRV_PCM_FMTBIT_FLOAT64_LE
#define SNDRV_PCM_FMTBIT_IEC958_SUBFRAME SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE
+#define SNDRV_PCM_FMTBIT_S20 SNDRV_PCM_FMTBIT_S20_LE
+#define SNDRV_PCM_FMTBIT_U20 SNDRV_PCM_FMTBIT_U20_LE
#endif
#ifdef SNDRV_BIG_ENDIAN
#define SNDRV_PCM_FMTBIT_S16 SNDRV_PCM_FMTBIT_S16_BE
@@ -213,6 +219,8 @@ struct snd_pcm_ops {
#define SNDRV_PCM_FMTBIT_FLOAT SNDRV_PCM_FMTBIT_FLOAT_BE
#define SNDRV_PCM_FMTBIT_FLOAT64 SNDRV_PCM_FMTBIT_FLOAT64_BE
#define SNDRV_PCM_FMTBIT_IEC958_SUBFRAME SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_BE
+#define SNDRV_PCM_FMTBIT_S20 SNDRV_PCM_FMTBIT_S20_BE
+#define SNDRV_PCM_FMTBIT_U20 SNDRV_PCM_FMTBIT_U20_BE
#endif

struct snd_pcm_file {
diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h
index 58acd00cae19..d970879944fc 100644
--- a/include/sound/soc-dai.h
+++ b/include/sound/soc-dai.h
@@ -102,6 +102,8 @@ struct snd_compr_stream;
SNDRV_PCM_FMTBIT_S16_BE |\
SNDRV_PCM_FMTBIT_S20_3LE |\
SNDRV_PCM_FMTBIT_S20_3BE |\
+ SNDRV_PCM_FMTBIT_S20_LE |\
+ SNDRV_PCM_FMTBIT_S20_BE |\
SNDRV_PCM_FMTBIT_S24_3LE |\
SNDRV_PCM_FMTBIT_S24_3BE |\
SNDRV_PCM_FMTBIT_S32_LE |\
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
index c227ccba60ae..07d61583fd02 100644
--- a/include/uapi/sound/asound.h
+++ b/include/uapi/sound/asound.h
@@ -214,6 +214,11 @@ typedef int __bitwise snd_pcm_format_t;
#define SNDRV_PCM_FORMAT_IMA_ADPCM ((__force snd_pcm_format_t) 22)
#define SNDRV_PCM_FORMAT_MPEG ((__force snd_pcm_format_t) 23)
#define SNDRV_PCM_FORMAT_GSM ((__force snd_pcm_format_t) 24)
+#define SNDRV_PCM_FORMAT_S20_LE ((__force snd_pcm_format_t) 25) /* in four bytes, LSB justified */
+#define SNDRV_PCM_FORMAT_S20_BE ((__force snd_pcm_format_t) 26) /* in four bytes, LSB justified */
+#define SNDRV_PCM_FORMAT_U20_LE ((__force snd_pcm_format_t) 27) /* in four bytes, LSB justified */
+#define SNDRV_PCM_FORMAT_U20_BE ((__force snd_pcm_format_t) 28) /* in four bytes, LSB justified */
+/* gap in the numbering for a future standard linear format */
#define SNDRV_PCM_FORMAT_SPECIAL ((__force snd_pcm_format_t) 31)
#define SNDRV_PCM_FORMAT_S24_3LE ((__force snd_pcm_format_t) 32) /* in three bytes */
#define SNDRV_PCM_FORMAT_S24_3BE ((__force snd_pcm_format_t) 33) /* in three bytes */
@@ -248,6 +253,8 @@ typedef int __bitwise snd_pcm_format_t;
#define SNDRV_PCM_FORMAT_FLOAT SNDRV_PCM_FORMAT_FLOAT_LE
#define SNDRV_PCM_FORMAT_FLOAT64 SNDRV_PCM_FORMAT_FLOAT64_LE
#define SNDRV_PCM_FORMAT_IEC958_SUBFRAME SNDRV_PCM_FORMAT_IEC958_SUBFRAME_LE
+#define SNDRV_PCM_FORMAT_S20 SNDRV_PCM_FORMAT_S20_LE
+#define SNDRV_PCM_FORMAT_U20 SNDRV_PCM_FORMAT_U20_LE
#endif
#ifdef SNDRV_BIG_ENDIAN
#define SNDRV_PCM_FORMAT_S16 SNDRV_PCM_FORMAT_S16_BE
@@ -259,6 +266,8 @@ typedef int __bitwise snd_pcm_format_t;
#define SNDRV_PCM_FORMAT_FLOAT SNDRV_PCM_FORMAT_FLOAT_BE
#define SNDRV_PCM_FORMAT_FLOAT64 SNDRV_PCM_FORMAT_FLOAT64_BE
#define SNDRV_PCM_FORMAT_IEC958_SUBFRAME SNDRV_PCM_FORMAT_IEC958_SUBFRAME_BE
+#define SNDRV_PCM_FORMAT_S20 SNDRV_PCM_FORMAT_S20_BE
+#define SNDRV_PCM_FORMAT_U20 SNDRV_PCM_FORMAT_U20_BE
#endif

typedef int __bitwise snd_pcm_subformat_t;
diff --git a/sound/core/pcm_misc.c b/sound/core/pcm_misc.c
index 9be81025372f..c4eb561d2008 100644
--- a/sound/core/pcm_misc.c
+++ b/sound/core/pcm_misc.c
@@ -163,13 +163,30 @@ static struct pcm_format_data pcm_formats[(INT)SNDRV_PCM_FORMAT_LAST+1] = {
.width = 32, .phys = 32, .le = 0, .signd = 0,
.silence = { 0x69, 0x69, 0x69, 0x69 },
},
- /* FIXME: the following three formats are not defined properly yet */
+ /* FIXME: the following two formats are not defined properly yet */
[SNDRV_PCM_FORMAT_MPEG] = {
.le = -1, .signd = -1,
},
[SNDRV_PCM_FORMAT_GSM] = {
.le = -1, .signd = -1,
},
+ [SNDRV_PCM_FORMAT_S20_LE] = {
+ .width = 20, .phys = 32, .le = 1, .signd = 1,
+ .silence = {},
+ },
+ [SNDRV_PCM_FORMAT_S20_BE] = {
+ .width = 20, .phys = 32, .le = 0, .signd = 1,
+ .silence = {},
+ },
+ [SNDRV_PCM_FORMAT_U20_LE] = {
+ .width = 20, .phys = 32, .le = 1, .signd = 0,
+ .silence = { 0x00, 0x00, 0x08, 0x00 },
+ },
+ [SNDRV_PCM_FORMAT_U20_BE] = {
+ .width = 20, .phys = 32, .le = 0, .signd = 0,
+ .silence = { 0x00, 0x08, 0x00, 0x00 },
+ },
+ /* FIXME: the following format is not defined properly yet */
[SNDRV_PCM_FORMAT_SPECIAL] = {
.le = -1, .signd = -1,
},