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Commit d853455a authored by Meng Wang's avatar Meng Wang Committed by Gerrit - the friendly Code Review server
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ALSA: PCM: User control API implementation 



Introduced a new helper function snd_pcm_add_usr_ctls() to
create control elements representing the user control for each
PCM (sub)stream

Change-Id: I9f69470ff2c5d6df8d1fdc2e1c2caf198076076e
Signed-off-by: default avatarJayasena Sangaraboina <jsanga@codeaurora.org>
Signed-off-by: default avatarBanajit Goswami <bgoswami@codeaurora.org>
Signed-off-by: default avatarSudheer Papothi <spapothi@codeaurora.org>
Signed-off-by: default avatarMeng Wang <mwang@codeaurora.org>
parent b0b44cce

include/sound/pcm.h

+25 −0
Original line number Diff line number Diff line
@@ -531,6 +531,7 @@ struct snd_pcm_str { 
#endif

	struct snd_kcontrol *chmap_kctl; /* channel-mapping controls */

	struct snd_kcontrol *vol_kctl; /* volume controls */

	struct snd_kcontrol *usr_kctl; /* user controls */

	struct device dev;

};
@@ -1475,6 +1476,30 @@ int snd_pcm_add_volume_ctls(struct snd_pcm *pcm, int stream, 
			   unsigned long private_value,

			   struct snd_pcm_volume **info_ret);



/*

 * PCM User control API

 */

/* array element of usr elem */

struct snd_pcm_usr_elem {

	int val[128];

};



/* pp information; retrieved via snd_kcontrol_chip() */

struct snd_pcm_usr {

	struct snd_pcm *pcm;	/* assigned PCM instance */

	int stream;		/* PLAYBACK or CAPTURE */

	struct snd_kcontrol *kctl;

	const struct snd_pcm_usr_elem *usr;

	int max_length;

	void *private_data;	/* optional: private data pointer */

};



int snd_pcm_add_usr_ctls(struct snd_pcm *pcm, int stream,

			 const struct snd_pcm_usr_elem *usr,

			 int max_length, int max_control_str_len,

			 unsigned long private_value,

			 struct snd_pcm_usr **info_ret);



/* printk helpers */

#define pcm_err(pcm, fmt, args...) \

	dev_err((pcm)->card->dev, fmt, ##args)

sound/core/pcm.c

+4 −0
Original line number Diff line number Diff line
@@ -879,6 +879,10 @@ static void free_chmap(struct snd_pcm_str *pstr) 
		snd_ctl_remove(pstr->pcm->card, pstr->vol_kctl);

		pstr->vol_kctl = NULL;

	}

	if (pstr->usr_kctl) {

		snd_ctl_remove(pstr->pcm->card, pstr->usr_kctl);

		pstr->usr_kctl = NULL;

	}

}



static void snd_pcm_free_stream(struct snd_pcm_str * pstr)

sound/core/pcm_lib.c

+93 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ 
#endif



#define STRING_LENGTH_OF_INT 12

#define MAX_USR_CTRL_CNT 128



static int fill_silence_frames(struct snd_pcm_substream *substream,

			       snd_pcm_uframes_t off, snd_pcm_uframes_t frames);
@@ -2572,3 +2573,95 @@ int snd_pcm_add_volume_ctls(struct snd_pcm *pcm, int stream, 
	return 0;

}

EXPORT_SYMBOL(snd_pcm_add_volume_ctls);



static int pcm_usr_ctl_info(struct snd_kcontrol *kcontrol,

			    struct snd_ctl_elem_info *uinfo)

{

	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;

	uinfo->count = MAX_USR_CTRL_CNT;

	uinfo->value.integer.min = 0;

	uinfo->value.integer.max = INT_MAX;

	return 0;

}



static void pcm_usr_ctl_private_free(struct snd_kcontrol *kcontrol)

{

	struct snd_pcm_usr *info = snd_kcontrol_chip(kcontrol);



	info->pcm->streams[info->stream].usr_kctl = NULL;

	kfree(info);

}



/**

 * snd_pcm_add_usr_ctls - create user control elements

 * @pcm: the assigned PCM instance

 * @stream: stream direction

 * @max_length: the max length of the user parameter of stream

 * @private_value: the value passed to each kcontrol's private_value field

 * @info_ret: store struct snd_pcm_usr instance if non-NULL

 *

 * Create usr control elements assigned to the given PCM stream(s).

 * Returns zero if succeed, or a negative error value.

 */

int snd_pcm_add_usr_ctls(struct snd_pcm *pcm, int stream,

			 const struct snd_pcm_usr_elem *usr,

			 int max_length, int max_kctrl_str_len,

			 unsigned long private_value,

			 struct snd_pcm_usr **info_ret)

{

	struct snd_pcm_usr *info;

	struct snd_kcontrol_new knew = {

		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,

		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,

		.info = pcm_usr_ctl_info,

	};

	int err;

	char *buf;



	info = kzalloc(sizeof(*info), GFP_KERNEL);

	if (!info)

		return -ENOMEM;



	info->pcm = pcm;

	info->stream = stream;

	info->usr = usr;

	info->max_length = max_length;

	buf = kzalloc(max_kctrl_str_len, GFP_KERNEL);

	if (!buf) {

		pr_err("%s: buffer allocation failed\n", __func__);

		kfree(info);

		return -ENOMEM;

	}

	knew.name = buf;

	if (stream == SNDRV_PCM_STREAM_PLAYBACK)

		snprintf(buf, max_kctrl_str_len, "%s %d %s",

			"Playback", pcm->device, "User kcontrol");

	else

		snprintf(buf, max_kctrl_str_len, "%s %d %s",

			"Capture", pcm->device, "User kcontrol");

	knew.device = pcm->device;

	knew.count = pcm->streams[stream].substream_count;

	knew.private_value = private_value;

	info->kctl = snd_ctl_new1(&knew, info);

	if (!info->kctl) {

		kfree(info);

		kfree(knew.name);

		pr_err("%s: snd_ctl_new failed\n", __func__);

		return -ENOMEM;

	}

	info->kctl->private_free = pcm_usr_ctl_private_free;

	err = snd_ctl_add(pcm->card, info->kctl);

	if (err < 0) {

		kfree(info);

		kfree(knew.name);

		pr_err("%s: snd_ctl_add failed:%d\n", __func__,

			err);

		return -ENOMEM;

	}

	pcm->streams[stream].usr_kctl = info->kctl;

	if (info_ret)

		*info_ret = info;

	kfree(knew.name);

	return 0;

}

EXPORT_SYMBOL(snd_pcm_add_usr_ctls);