[PATCH 2/2] pcm: iec958: set channel status bits according to rate and format

[Matthias Reichl]

This mimics snd_pcm_create_iec958_consumer in the kernel.

The rate and wordlength bits will only be modified if they are
set to "not indicated", which is now the default if no status
option is used.

This allows applications to override parameters determined from
the stream or implement channel status bits extensions without
needing to change pcm_iec958 code.

Signed-off-by: Matthias Reichl <hias at horus.com>
---
 src/pcm/pcm_iec958.c | 80 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 76 insertions(+), 4 deletions(-)

diff --git a/src/pcm/pcm_iec958.c b/src/pcm/pcm_iec958.c
index 17ade957..a11a0439 100644
--- a/src/pcm/pcm_iec958.c
+++ b/src/pcm/pcm_iec958.c
@@ -365,9 +365,80 @@ static int snd_pcm_iec958_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * params
 			iec->byteswap = format != SND_PCM_FORMAT_IEC958_SUBFRAME;
 		}
 	}
-	/* FIXME: needs to adjust status_bits according to the format
-	 *        and sample rate
-	 */
+
+	if ((iec->status[0] & IEC958_AES0_PROFESSIONAL) == 0) {
+		if ((iec->status[3] & IEC958_AES3_CON_FS) == IEC958_AES3_CON_FS_NOTID) {
+			unsigned int rate = 0;
+			unsigned char fs;
+
+			err = INTERNAL(snd_pcm_hw_params_get_rate)(params, &rate, 0);
+			if (err < 0)
+				rate = 0;
+
+			switch (rate) {
+			case 22050:
+				fs = IEC958_AES3_CON_FS_22050;
+				break;
+			case 24000:
+				fs = IEC958_AES3_CON_FS_24000;
+				break;
+			case 32000:
+				fs = IEC958_AES3_CON_FS_32000;
+				break;
+			case 44100:
+				fs = IEC958_AES3_CON_FS_44100;
+				break;
+			case 48000:
+				fs = IEC958_AES3_CON_FS_48000;
+				break;
+			case 88200:
+				fs = IEC958_AES3_CON_FS_88200;
+				break;
+			case 96000:
+				fs = IEC958_AES3_CON_FS_96000;
+				break;
+			case 176400:
+				fs = IEC958_AES3_CON_FS_176400;
+				break;
+			case 192000:
+				fs = IEC958_AES3_CON_FS_192000;
+				break;
+			case 768000:
+				fs = IEC958_AES3_CON_FS_768000;
+				break;
+			default:
+				fs = IEC958_AES3_CON_FS_NOTID;
+				break;
+			}
+
+			iec->status[3] &= ~IEC958_AES3_CON_FS;
+			iec->status[3] |= fs;
+		}
+
+		if ((iec->status[4] & IEC958_AES4_CON_WORDLEN) == IEC958_AES4_CON_WORDLEN_NOTID) {
+			unsigned char ws;
+			switch (snd_pcm_format_width(format)) {
+			case 16:
+				ws = IEC958_AES4_CON_WORDLEN_20_16;
+				break;
+			case 18:
+				ws = IEC958_AES4_CON_WORDLEN_22_18;
+				break;
+			case 20:
+				ws = IEC958_AES4_CON_WORDLEN_20_16 | IEC958_AES4_CON_MAX_WORDLEN_24;
+				break;
+			case 24:
+			case 32: /* Assume 24-bit width for 32-bit samples. */
+				ws = IEC958_AES4_CON_WORDLEN_24_20 | IEC958_AES4_CON_MAX_WORDLEN_24;
+				break;
+			default:
+				ws = IEC958_AES4_CON_WORDLEN_NOTID;
+				break;
+			}
+			iec->status[4] &= ~(IEC958_AES4_CON_MAX_WORDLEN_24 | IEC958_AES4_CON_WORDLEN);
+			iec->status[4] |= ws;
+		}
+	}
 	return 0;
 }
 
@@ -504,7 +575,8 @@ int snd_pcm_iec958_open(snd_pcm_t **pcmp, const char *name, snd_pcm_format_t sfo
 		IEC958_AES0_CON_EMPHASIS_NONE,
 		IEC958_AES1_CON_ORIGINAL | IEC958_AES1_CON_PCM_CODER,
 		0,
-		IEC958_AES3_CON_FS_48000
+		IEC958_AES3_CON_FS_NOTID, /* will be set in hwparams */
+		IEC958_AES4_CON_WORDLEN_NOTID /* will be set in hwparams */
 	};
 
 	assert(pcmp && slave);
-- 
2.20.1