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Commit cda3673c authored by Subhash Chandra Bose Naripeddy's avatar Subhash Chandra Bose Naripeddy Committed by Jayasena Sangaraboina
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ALSA: PCM: User contol 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: I1a6c3038085c27663b08dc1a9af714aa0f63730b
Signed-off-by: default avatarJayasena Sangaraboina <jsanga@codeaurora.org>
parent 563010bc

include/sound/pcm.h

+25 −0
Original line number Diff line number Diff line
@@ -453,6 +453,7 @@ 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 snd_pcm {
@@ -1173,4 +1174,28 @@ 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);



#endif /* __SOUND_PCM_H */

sound/core/pcm.c

+4 −0
Original line number Diff line number Diff line
@@ -1126,6 +1126,10 @@ static int snd_pcm_dev_disconnect(struct snd_device *device) 
			snd_ctl_remove(pcm->card, pcm->streams[cidx].vol_kctl);

			pcm->streams[cidx].vol_kctl = NULL;

		}

		if (pcm->streams[cidx].usr_kctl) {

			snd_ctl_remove(pcm->card, pcm->streams[cidx].usr_kctl);

			pcm->streams[cidx].usr_kctl = NULL;

		}

	}

	mutex_unlock(&pcm->open_mutex);

 unlock:

sound/core/pcm_lib.c

+93 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#include <sound/timer.h>



#define STRING_LENGTH_OF_INT 12

#define MAX_USR_CTRL_CNT 128



/*

 * fill ring buffer with silence
@@ -2699,3 +2700,95 @@ int snd_pcm_add_volume_ctls(struct snd_pcm *pcm, int stream, 
	return 0;

}

EXPORT_SYMBOL_GPL(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) {

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

		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);