[alsa-devel] [PATCH 1/3] ALSA: pcm: add IEC958 channel status update
Moise Gergaud
moise.gergaud at st.com
Wed Dec 2 15:22:04 CET 2015
Add a helper to update only the IEC958 channel status sampling freq and
word length parameters from an ALSA snd_pcm_runtime structure, taking
account of the sample rate and sample size.
Signed-off-by: Moise Gergaud <moise.gergaud at st.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen at st.com>
---
include/sound/pcm_iec958.h | 19 ++++++++++-
sound/core/pcm_iec958.c | 78 +++++++++++++++++++++++++++++++---------------
2 files changed, 71 insertions(+), 26 deletions(-)
diff --git a/include/sound/pcm_iec958.h b/include/sound/pcm_iec958.h
index 0eed397..0c84c69 100644
--- a/include/sound/pcm_iec958.h
+++ b/include/sound/pcm_iec958.h
@@ -3,7 +3,24 @@
#include <linux/types.h>
+#ifdef CONFIG_SND_PCM_IEC958
int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
- size_t len);
+ size_t len);
+
+int snd_pcm_update_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
+ size_t len);
+#else
+int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
+ size_t len)
+{
+ return len;
+}
+
+int snd_pcm_update_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
+ size_t len)
+{
+ return len;
+}
+#endif
#endif
diff --git a/sound/core/pcm_iec958.c b/sound/core/pcm_iec958.c
index 36b2d7a..abe3967 100644
--- a/sound/core/pcm_iec958.c
+++ b/sound/core/pcm_iec958.c
@@ -11,67 +11,72 @@
#include <sound/pcm.h>
#include <sound/pcm_iec958.h>
-/**
- * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status
+/*
+ * snd_pcm_update_iec958_consumer - update consumer format IEC958 channel status
* @runtime: pcm runtime structure with ->rate filled in
* @cs: channel status buffer, at least four bytes
* @len: length of channel status buffer
*
- * Create the consumer format channel status data in @cs of maximum size
- * @len corresponding to the parameters of the PCM runtime @runtime.
- *
- * Drivers may wish to tweak the contents of the buffer after creation.
+ * Update sampling frequency and word length parameters of the consumer format
+ * channel status data in @cs of maximum size @len.
+ * Values correspond to the rate and format parameters of the PCM runtime
+ * @runtime.
*
* Returns: length of buffer, or negative error code if something failed.
*/
-int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
- size_t len)
+int snd_pcm_update_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
+ size_t len)
{
- unsigned int fs, ws;
-
if (len < 4)
return -EINVAL;
+ cs[3] &= ~IEC958_AES3_CON_FS;
+
switch (runtime->rate) {
+ case 22050:
+ cs[3] |= IEC958_AES3_CON_FS_22050;
+ break;
case 32000:
- fs = IEC958_AES3_CON_FS_32000;
+ cs[3] |= IEC958_AES3_CON_FS_32000;
break;
case 44100:
- fs = IEC958_AES3_CON_FS_44100;
+ cs[3] |= IEC958_AES3_CON_FS_44100;
break;
case 48000:
- fs = IEC958_AES3_CON_FS_48000;
+ cs[3] |= IEC958_AES3_CON_FS_48000;
break;
case 88200:
- fs = IEC958_AES3_CON_FS_88200;
+ cs[3] |= IEC958_AES3_CON_FS_88200;
break;
case 96000:
- fs = IEC958_AES3_CON_FS_96000;
+ cs[3] |= IEC958_AES3_CON_FS_96000;
break;
case 176400:
- fs = IEC958_AES3_CON_FS_176400;
+ cs[3] |= IEC958_AES3_CON_FS_176400;
break;
case 192000:
- fs = IEC958_AES3_CON_FS_192000;
+ cs[3] |= IEC958_AES3_CON_FS_192000;
break;
default:
return -EINVAL;
}
if (len > 4) {
+ cs[4] &= ~IEC958_AES4_CON_WORDLEN;
+
switch (snd_pcm_format_width(runtime->format)) {
case 16:
- ws = IEC958_AES4_CON_WORDLEN_20_16;
+ cs[4] |= IEC958_AES4_CON_WORDLEN_20_16;
break;
case 18:
- ws = IEC958_AES4_CON_WORDLEN_22_18;
+ cs[4] |= IEC958_AES4_CON_WORDLEN_22_18;
break;
case 20:
- ws = IEC958_AES4_CON_WORDLEN_20_16 |
+ cs[4] |= IEC958_AES4_CON_WORDLEN_20_16 |
IEC958_AES4_CON_MAX_WORDLEN_24;
break;
case 24:
- ws = IEC958_AES4_CON_WORDLEN_24_20 |
+ cs[4] |= IEC958_AES4_CON_WORDLEN_24_20 |
IEC958_AES4_CON_MAX_WORDLEN_24;
break;
@@ -80,15 +85,38 @@ int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
}
}
+ return len;
+}
+EXPORT_SYMBOL(snd_pcm_update_iec958_consumer);
+
+/**
+ * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status
+ * @runtime: pcm runtime structure with ->rate filled in
+ * @cs: channel status buffer, at least four bytes
+ * @len: length of channel status buffer
+ *
+ * Create the consumer format channel status data in @cs of maximum size
+ * @len corresponding to the parameters of the PCM runtime @runtime.
+ *
+ * Drivers may wish to tweak the contents of the buffer after creation.
+ *
+ * Returns: length of buffer, or negative error code if something failed.
+ */
+int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
+ size_t len)
+{
+ int ret;
+
memset(cs, 0, len);
+ ret = snd_pcm_update_iec958_consumer(runtime, cs, len);
+ if (ret < 0)
+ return ret;
+
cs[0] = IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE;
cs[1] = IEC958_AES1_CON_GENERAL;
cs[2] = IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC;
- cs[3] = IEC958_AES3_CON_CLOCK_1000PPM | fs;
-
- if (len > 4)
- cs[4] = ws;
+ cs[3] |= IEC958_AES3_CON_CLOCK_1000PPM;
return len;
}
--
1.9.1
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