Add a helper to create the IEC958 channel status from an ALSA
snd_pcm_runtime structure, taking account of the sample rate and
sample size.
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
---
include/sound/pcm_iec958.h | 9 +++++
sound/core/Kconfig | 3 ++
sound/core/Makefile | 1 +
sound/core/pcm_iec958.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 108 insertions(+)
create mode 100644 include/sound/pcm_iec958.h
create mode 100644 sound/core/pcm_iec958.c
diff --git a/include/sound/pcm_iec958.h b/include/sound/pcm_iec958.h
new file mode 100644
index 000000000000..0eed397aca8e
--- /dev/null
+++ b/include/sound/pcm_iec958.h
@@ -0,0 +1,9 @@
+#ifndef __SOUND_PCM_IEC958_H
+#define __SOUND_PCM_IEC958_H
+
+#include <linux/types.h>
+
+int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
+ size_t len);
+
+#endif
diff --git a/sound/core/Kconfig b/sound/core/Kconfig
index b534c8a6046b..1507469425ec 100644
--- a/sound/core/Kconfig
+++ b/sound/core/Kconfig
@@ -9,6 +9,9 @@ config SND_PCM
config SND_PCM_ELD
bool
+config SND_PCM_IEC958
+ bool
+
config SND_DMAENGINE_PCM
tristate
diff --git a/sound/core/Makefile b/sound/core/Makefile
index 591b49157b4d..2b925fcc95ea 100644
--- a/sound/core/Makefile
+++ b/sound/core/Makefile
@@ -14,6 +14,7 @@ snd-pcm-y := pcm.o pcm_native.o pcm_lib.o pcm_timer.o pcm_misc.o \
pcm_memory.o memalloc.o
snd-pcm-$(CONFIG_SND_DMA_SGBUF) += sgbuf.o
snd-pcm-$(CONFIG_SND_PCM_ELD) += pcm_drm_eld.o
+snd-pcm-$(CONFIG_SND_PCM_IEC958) += pcm_iec958.o
# for trace-points
CFLAGS_pcm_lib.o := -I$(src)
diff --git a/sound/core/pcm_iec958.c b/sound/core/pcm_iec958.c
new file mode 100644
index 000000000000..36b2d7aca1bd
--- /dev/null
+++ b/sound/core/pcm_iec958.c
@@ -0,0 +1,95 @@
+/*
+ * PCM DRM helpers
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/export.h>
+#include <linux/types.h>
+#include <sound/asoundef.h>
+#include <sound/pcm.h>
+#include <sound/pcm_iec958.h>
+
+/**
+ * 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)
+{
+ unsigned int fs, ws;
+
+ if (len < 4)
+ return -EINVAL;
+
+ switch (runtime->rate) {
+ 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;
+ default:
+ return -EINVAL;
+ }
+
+ if (len > 4) {
+ switch (snd_pcm_format_width(runtime->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:
+ ws = IEC958_AES4_CON_WORDLEN_24_20 |
+ IEC958_AES4_CON_MAX_WORDLEN_24;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+ }
+
+ memset(cs, 0, len);
+
+ 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;
+
+ return len;
+}
+EXPORT_SYMBOL(snd_pcm_create_iec958_consumer);
--
1.8.3.1
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