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Commit 9203dd01 authored by Russell King's avatar Russell King Committed by Takashi Iwai
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ALSA: pcm: add IEC958 channel status helper 



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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Reviwed-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 838d1631

include/sound/pcm_iec958.h

0 → 100644
+9 −0
Original line number Diff line number Diff line 
#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
Original line number Diff line number Diff line
@@ -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
Original line number Diff line number Diff line 
/*

 *  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);