pcm: Add MSBITS_20 and MSBITS_24 subformat options

Improve granularity of format selection for S32/U32 formats by adding
masks representing 20 and 24 most significant bits.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>

include/pcm.h

@@ -286,7 +286,11 @@ typedef enum _snd_pcm_subformat {
 	SND_PCM_SUBFORMAT_UNKNOWN = -1,
 	/** Standard */
 	SND_PCM_SUBFORMAT_STD = 0,
-	SND_PCM_SUBFORMAT_LAST = SND_PCM_SUBFORMAT_STD
+	/** 20 most significant bits **/
+	SND_PCM_SUBFORMAT_MSBITS_20 = 1,
+	/** 24 most significant bits **/
+	SND_PCM_SUBFORMAT_MSBITS_24 = 2,
+	SND_PCM_SUBFORMAT_LAST = SND_PCM_SUBFORMAT_MSBITS_24
 } snd_pcm_subformat_t;
 
 /** PCM state */

include/sound/uapi/asound.h

@@ -274,7 +274,9 @@ typedef int __bitwise snd_pcm_format_t;
 
 typedef int __bitwise snd_pcm_subformat_t;
 #define	SNDRV_PCM_SUBFORMAT_STD		((snd_pcm_subformat_t) 0)
-#define	SNDRV_PCM_SUBFORMAT_LAST	SNDRV_PCM_SUBFORMAT_STD
+#define	SNDRV_PCM_SUBFORMAT_MSBITS_20	((snd_pcm_subformat_t) 1)
+#define	SNDRV_PCM_SUBFORMAT_MSBITS_24	((snd_pcm_subformat_t) 2)
+#define	SNDRV_PCM_SUBFORMAT_LAST	SNDRV_PCM_SUBFORMAT_MSBITS_24
 
 #define SNDRV_PCM_INFO_MMAP		0x00000001	/* hardware supports mmap */
 #define SNDRV_PCM_INFO_MMAP_VALID	0x00000002	/* period data are valid during transfer */

src/pcm/pcm.c

@@ -2061,10 +2061,14 @@ static const char *const snd_pcm_type_names[] = {
 
 static const char *const snd_pcm_subformat_names[] = {
 	SUBFORMAT(STD), 
+	SUBFORMAT(MSBITS_20),
+	SUBFORMAT(MSBITS_24),
 };
 
 static const char *const snd_pcm_subformat_descriptions[] = {
 	SUBFORMATD(STD, "Standard"), 
+	SUBFORMATD(MSBITS_20, "20 most significant bits"),
+	SUBFORMATD(MSBITS_24, "24 most significant bits"),
 };
 
 static const char *const snd_pcm_start_mode_names[] = {

src/pcm/pcm_params.c

@@ -2008,7 +2008,9 @@ static const snd_mask_t refine_masks[SND_PCM_HW_PARAM_LAST_MASK - SND_PCM_HW_PAR
 	},
 	[SND_PCM_HW_PARAM_SUBFORMAT - SND_PCM_HW_PARAM_FIRST_MASK] = {
 		.bits = {
-			PCM_BIT(SNDRV_PCM_SUBFORMAT_STD)
+			PCM_BIT(SNDRV_PCM_SUBFORMAT_STD),
+			PCM_BIT(SNDRV_PCM_SUBFORMAT_MSBITS_20),
+			PCM_BIT(SNDRV_PCM_SUBFORMAT_MSBITS_24)
 		},
 	},
 };