ALSA: pcm: add IEC958 channel status helper (9203dd01) · Commits · 戴 / test

include/sound/pcm_iec958.h

0 → 100644

+9 −0

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		#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

sound/core/Kconfig

+3 −0

Original line number	Diff line number	Diff line
		@@ -9,6 +9,9 @@ config SND_PCM
		config SND_PCM_ELD
		bool

		config SND_PCM_IEC958
		bool

		config SND_DMAENGINE_PCM
		tristate

sound/core/Makefile

+1 −0

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		@@ -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)

sound/core/pcm_iec958.c

0 → 100644

+95 −0

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		/*
		* 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);

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