Documentation and simple config for one card

1 files changed, 82 insertions, 0 deletions

diff --git a/plugins/alsa/alsa-plug-vol.c b/plugins/alsa/alsa-plug-vol.c
new file mode 100644
index 0000000..42d1e0b
--- /dev/null
+++ b/plugins/alsa/alsa-plug-vol.c
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2018 "IoT.bzh"
+ * Author Fulup Ar Foll <fulup@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#define _GNU_SOURCE  // needed for vasprintf
+
+#include "alsa-softmixer.h"
+
+ALSA_PLUG_PROTO(softvol);
+
+PUBLIC AlsaPcmInfoT* AlsaCreateVol(CtlSourceT *source, const char *pcmName, AlsaPcmInfoT* ctlTarget, AlsaPcmInfoT* pcmSlave) {
+
+    snd_config_t *volConfig, *elemConfig, *slaveConfig, *controlConfig,*pcmConfig;
+    int error = 0;
+    AlsaPcmInfoT *pcmPlug= malloc(sizeof(AlsaPcmInfoT));
+    pcmPlug->devid= pcmName;
+
+    // refresh global alsalib config and create PCM top config
+    snd_config_update();
+    error += snd_config_top(&volConfig);
+    error += snd_config_set_id (volConfig, pcmPlug->devid);
+    error += snd_config_imake_string(&elemConfig, "type", "softvol");
+    error += snd_config_add(volConfig, elemConfig);
+    if (error) goto OnErrorExit;
+    
+    // add slave leaf
+    error += snd_config_make_compound(&slaveConfig, "slave", 0);
+    error += snd_config_imake_string(&elemConfig, "pcm", pcmSlave->devid);
+    error += snd_config_add(slaveConfig, elemConfig);
+    error += snd_config_add(volConfig, slaveConfig);
+    if (error) goto OnErrorExit;
+    
+    // add control leaf
+    error += snd_config_make_compound(&controlConfig, "control", 0);
+    error += snd_config_imake_string(&elemConfig, "name", pcmName);
+    error += snd_config_add(controlConfig, elemConfig);
+    error += snd_config_imake_integer(&elemConfig, "card", ctlTarget->cardid);
+    error += snd_config_add(controlConfig, elemConfig);
+    error += snd_config_add(volConfig, controlConfig);
+    if (error) goto OnErrorExit; 
+    
+    // update top config to access previous plugin PCM
+    snd_config_update();
+    
+    error = _snd_pcm_softvol_open(&pcmPlug->handle, pcmName, snd_config, volConfig, SND_PCM_STREAM_PLAYBACK , SND_PCM_NONBLOCK); 
+    if (error) {
+        AFB_ApiError(source->api, "AlsaCreateVol: fail to create Plug=%s Slave=%s", pcmPlug->devid, pcmSlave->devid);
+        goto OnErrorExit;
+    }
+  
+    error += snd_config_search(snd_config, "pcm", &pcmConfig);    
+    error += snd_config_add(pcmConfig, volConfig);
+    if (!error) {
+        AFB_ApiError(source->api, "AlsaCreateDmix: fail to add configDMIX=%s", pcmPlug->devid);
+        goto OnErrorExit;
+    }
+    
+    // Debug config & pcm
+    AlsaDumpCtlConfig (source, volConfig, 1);
+    //AlsaDumpPcmInfo(source, pcmPlug->handle, "pcmPlug->handle");
+    AFB_ApiNotice(source->api, "AlsaCreateVol: %s done", pcmPlug->devid);
+    return pcmPlug;
+
+OnErrorExit:
+    AFB_ApiNotice(source->api, "AlsaCreateVol: OnErrorExit");
+    AlsaDumpCtlConfig(source, volConfig, 1);
+    return NULL;
+}
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