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-rw-r--r--ALSA-afb/Alsa-AddCtl.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/ALSA-afb/Alsa-AddCtl.c b/ALSA-afb/Alsa-AddCtl.c
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+++ b/ALSA-afb/Alsa-AddCtl.c
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+/*
+ * AlsaUseCase -- provide low level interface with ALSA lib (extracted from alsa-json-gateway code)
+ * Copyright (C) 2015,2016,2017, 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/asoundlib.h>
+#include <systemd/sd-event.h>
+#include "Alsa-ApiHat.h"
+
+STATIC int addOneSndCtl(struct afb_req request, snd_ctl_t *ctlDev, json_object *ctlJ) {
+ snd_ctl_elem_info_t *cinfo;
+ int err;
+ int i;
+ unsigned int def_val;
+ json_object *jName, *jNumid, *jTmp;
+ const char *ctlName;
+ int ctlNumid, ctlMax, ctlMin, ctlStep, ctlCount, ctlSubDev;
+ snd_ctl_elem_type_t ctlType;
+ snd_ctl_elem_info_t *elemInfo;
+
+ // parse json ctl object
+ json_object_object_get_ex (ctlJ, "name" , &jName);
+ json_object_object_get_ex (ctlJ, "numid", &jNumid);
+ if (!jName || !jNumid) {
+ afb_req_fail_f (request, "ctl-invalid", "crl=%s name/numid missing", json_object_to_json_string(ctlJ));
+ goto OnErrorExit;
+ }
+
+ ctlName = json_object_to_json_string(jName);
+ ctlNumid = json_object_get_int(jNumid);
+
+ // default for json_object_get_int is zero
+ json_object_object_get_ex (ctlJ, "min" , &jTmp);
+ ctlMin = json_object_get_int(jTmp);
+
+ json_object_object_get_ex (ctlJ, "max" , &jTmp);
+ if (!jTmp) ctlMax=1;
+ else ctlMax = json_object_get_int(jTmp);
+
+ json_object_object_get_ex (ctlJ, "step" , &jTmp);
+ if (!jTmp) ctlStep=1;
+ else ctlStep = json_object_get_int(jTmp);
+
+ json_object_object_get_ex (ctlJ, "count" , &jTmp);
+ if (!jTmp) ctlCount=2;
+ else ctlCount = json_object_get_int(jTmp);
+
+ json_object_object_get_ex (ctlJ, "subdev" , &jTmp);
+ ctlSubDev = json_object_get_int(jTmp);
+
+ json_object_object_get_ex (ctlJ, "type" , &jTmp);
+ if (!jTmp) ctlType=SND_CTL_ELEM_TYPE_INTEGER;
+ else ctlType = json_object_get_int(jTmp);
+
+ // set info event ID and get value
+ snd_ctl_elem_info_alloca(&elemInfo);
+ snd_ctl_elem_info_set_name (elemInfo, ctlName); // map ctlInfo to ctlId elemInfo is updated !!!
+ snd_ctl_elem_info_set_numid(elemInfo, ctlNumid); // map ctlInfo to ctlId elemInfo is updated !!!
+
+ if (snd_ctl_elem_info(ctlDev, elemInfo) >= 0) {
+ afb_req_fail_f (request, "ctl-already-exist", "crl=%s name/numid not unique", json_object_to_json_string(ctlJ));
+ goto OnErrorExit;
+ }
+
+ snd_ctl_elem_info_set_subdevice(elemInfo, ctlSubDev);
+
+ switch (ctlType) {
+ case SND_CTL_ELEM_TYPE_BOOLEAN:
+ err = snd_ctl_add_boolean_elem_set(ctlDev, cinfo, 1, ctlCount);
+ if (err) {
+ afb_req_fail_f (request, "ctl-invalid-bool", "crl=%s invalid boolean data", json_object_to_json_string(ctlJ));
+ goto OnErrorExit;
+ }
+ break;
+
+ case SND_CTL_ELEM_TYPE_INTEGER:
+ break;
+
+ case SND_CTL_ELEM_TYPE_INTEGER64:
+ break;
+
+ case SND_CTL_ELEM_TYPE_ENUMERATED:
+ break;
+
+ case SND_CTL_ELEM_TYPE_BYTES:
+ break;
+
+ default:
+ afb_req_fail_f (request, "ctl-invalid-type", "crl=%s invalid/unknown type", json_object_to_json_string(ctlJ));
+ goto OnErrorExit;
+ }
+
+
+ snd_ctl_elem_write(ctlDev, &ctlElem);
+
+ return 0;
+
+ OnErrorExit:
+ return -1;
+}
+
+// Subscribe to every Alsa CtlEvent send by a given board
+PUBLIC void alsaAddCustomCtl (struct afb_req request) {
+ snd_ctl_t *ctlDev;
+ int err;
+ const char *devid, *ctls;
+ json_object *ctlsJ;
+
+ devid = afb_req_value(request, "devid");
+ if (!devid) {
+ afb_req_fail_f (request, "missing-devid", "devid=xxx missing");
+ goto OnErrorExit;
+ }
+
+ // open control interface for devid
+ err = snd_ctl_open(&ctlDev, devid, 0);
+ if (err < 0) {
+ ctlDev=NULL;
+ afb_req_fail_f (request, "devid-unknown", "SndCard devid=%s Not Found err=%s", queryValues.devid, snd_strerror(err));
+ goto OnErrorExit;
+ }
+
+ ctls = afb_req_value(request, "ctls");
+ if (!ctls) {
+ afb_req_fail_f (request, "missing-ctls", "ctls=[{name:xxx, numdid=xx, ...}] missing");
+ goto OnErrorExit;
+ }
+
+ ctlsJ = json_tokener_parse(ctls);
+ if (!ctlsJ) {
+ afb_req_fail_f (request, "ctls-notjson","ctls=%s not a valid json entry", ctls);
+ goto OnErrorExit;
+ };
+
+ enum json_type jtype= json_object_get_type(ctlsJ);
+ switch (jtype) {
+ int error;
+ json_object *ctlJ;
+
+ case json_type_array:
+ int count = json_object_array_length (ctlsJ);
+ for (int idx=0; idx < count; idx ++) {
+ ctlJ = json_object_array_get_idx (ctlsJ, idx);
+ error = alsaAddCtrl (request, ctlDev, ctlsJ);
+ if (error) goto OnErrorExit;
+ }
+ break;
+
+ case json_type_object:
+ error = alsaAddCtrl (request, ctlDev, ctlsJ);
+ if (error) goto OnErrorExit;
+ break;
+
+ default:
+ afb_req_fail_f (request, "ctls-notarray","ctls=%s not valid JSON control object", ctls);
+ goto OnErrorExit;
+ }
+
+ snd_ctl_close(ctlDev);
+ return;
+
+ OnErrorExit:
+ if (ctlDev) snd_ctl_close(ctlDev);
+ return;
+}
+