From f928605b0e173bc4b9614375820bd91ed1ee095e Mon Sep 17 00:00:00 2001 From: Sudheer Papothi Date: Fri, 29 Jan 2016 02:37:36 +0530 Subject: [PATCH] ALSA: PCM: volume API implementation Introduced a new helper function snd_pcm_add_volume_ctls() to create control elements representing the volume for each PCM (sub)stream. Signed-off-by: Damir Didjusto Signed-off-by: Banajit Goswami Signed-off-by: Sudheer Papothi --- include/sound/pcm.h | 25 ++++++++++++ sound/core/pcm.c | 4 ++ sound/core/pcm_lib.c | 90 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 119 insertions(+) diff --git a/include/sound/pcm.h b/include/sound/pcm.h index 06d919d95cac..048b456ca32d 100644 --- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -518,6 +518,7 @@ struct snd_pcm_str { #endif #endif struct snd_kcontrol *chmap_kctl; /* channel-mapping controls */ + struct snd_kcontrol *vol_kctl; /* volume controls */ struct device dev; }; @@ -1410,6 +1411,30 @@ static inline u64 pcm_format_to_bits(snd_pcm_format_t pcm_format) return 1ULL << (__force int) pcm_format; } +/* + * PCM Volume control API + */ +/* array element of volume */ +struct snd_pcm_volume_elem { + int volume; +}; + +/* pp information; retrieved via snd_kcontrol_chip() */ +struct snd_pcm_volume { + struct snd_pcm *pcm; /* assigned PCM instance */ + int stream; /* PLAYBACK or CAPTURE */ + struct snd_kcontrol *kctl; + const struct snd_pcm_volume_elem *volume; + int max_length; + void *private_data; /* optional: private data pointer */ +}; + +int snd_pcm_add_volume_ctls(struct snd_pcm *pcm, int stream, + const struct snd_pcm_volume_elem *volume, + int max_length, + unsigned long private_value, + struct snd_pcm_volume **info_ret); + /* printk helpers */ #define pcm_err(pcm, fmt, args...) \ dev_err((pcm)->card->dev, fmt, ##args) diff --git a/sound/core/pcm.c b/sound/core/pcm.c index 308c9ecf73db..e43571e70ef6 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -1139,6 +1139,10 @@ static int snd_pcm_dev_disconnect(struct snd_device *device) snd_ctl_remove(pcm->card, pcm->streams[cidx].chmap_kctl); pcm->streams[cidx].chmap_kctl = NULL; } + if (pcm->streams[cidx].vol_kctl) { + snd_ctl_remove(pcm->card, pcm->streams[cidx].vol_kctl); + pcm->streams[cidx].vol_kctl = NULL; + } } mutex_unlock(&pcm->open_mutex); mutex_unlock(®ister_mutex); diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index eeb9c6eee1b5..678b96aec203 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -41,6 +41,8 @@ #define trace_hw_ptr_error(substream, reason) #endif +#define STRING_LENGTH_OF_INT 12 + /* * fill ring buffer with silence * runtime->silence_start: starting pointer to silence area @@ -2568,6 +2570,23 @@ static void pcm_chmap_ctl_private_free(struct snd_kcontrol *kcontrol) kfree(info); } +static int pcm_volume_ctl_info(struct snd_kcontrol *kcontrol, + struct snd_ctl_elem_info *uinfo) +{ + uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; + uinfo->count = 1; + uinfo->value.integer.min = 0; + uinfo->value.integer.max = 0x2000; + return 0; +} + +static void pcm_volume_ctl_private_free(struct snd_kcontrol *kcontrol) +{ + struct snd_pcm_volume *info = snd_kcontrol_chip(kcontrol); + info->pcm->streams[info->stream].vol_kctl = NULL; + kfree(info); +} + /** * snd_pcm_add_chmap_ctls - create channel-mapping control elements * @pcm: the assigned PCM instance @@ -2627,3 +2646,74 @@ int snd_pcm_add_chmap_ctls(struct snd_pcm *pcm, int stream, return 0; } EXPORT_SYMBOL_GPL(snd_pcm_add_chmap_ctls); + +/** + * snd_pcm_add_volume_ctls - create volume control elements + * @pcm: the assigned PCM instance + * @stream: stream direction + * @max_length: the max length of the volume parameter of stream + * @private_value: the value passed to each kcontrol's private_value field + * @info_ret: store struct snd_pcm_volume instance if non-NULL + * + * Create volume control elements assigned to the given PCM stream(s). + * Returns zero if succeed, or a negative error value. + */ +int snd_pcm_add_volume_ctls(struct snd_pcm *pcm, int stream, + const struct snd_pcm_volume_elem *volume, + int max_length, + unsigned long private_value, + struct snd_pcm_volume **info_ret) +{ + struct snd_pcm_volume *info; + struct snd_kcontrol_new knew = { + .iface = SNDRV_CTL_ELEM_IFACE_MIXER, + .access = SNDRV_CTL_ELEM_ACCESS_TLV_READ | + SNDRV_CTL_ELEM_ACCESS_READWRITE, + .info = pcm_volume_ctl_info, + }; + int err; + int size; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + info->pcm = pcm; + info->stream = stream; + info->volume = volume; + info->max_length = max_length; + size = sizeof("Playback ") + sizeof(" Volume") + + STRING_LENGTH_OF_INT*sizeof(char) + 1; + knew.name = kzalloc(size, GFP_KERNEL); + if (!knew.name) { + kfree(info); + return -ENOMEM; + } + if (stream == SNDRV_PCM_STREAM_PLAYBACK) + snprintf(knew.name, size, "%s %d %s", + "Playback", pcm->device, "Volume"); + else + snprintf(knew.name, size, "%s %d %s", + "Capture", pcm->device, "Volume"); + 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); + return -ENOMEM; + } + info->kctl->private_free = pcm_volume_ctl_private_free; + err = snd_ctl_add(pcm->card, info->kctl); + if (err < 0) { + kfree(info); + kfree(knew.name); + return -ENOMEM; + } + pcm->streams[stream].vol_kctl = info->kctl; + if (info_ret) + *info_ret = info; + kfree(knew.name); + return 0; +} +EXPORT_SYMBOL_GPL(snd_pcm_add_volume_ctls);