fldigi - Initial work to enable PnP support for fldigi. Wrote a custom tool to map between an ALSA device and a PortAudio device.

src/et-portaudio/.gitignore

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+et-portaudio
+*.o
+conf.tmp

src/et-portaudio/Makefile

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+CC = gcc
+CFLAGS = -Wall -O2
+LDFLAGS = -lportaudio -lasound
+
+TARGET = et-portaudio
+SRC = main.c
+
+all: $(TARGET)
+
+$(TARGET): $(SRC)
+	$(CC) $(CFLAGS) -o $(TARGET) $(SRC) $(LDFLAGS)
+
+clean:
+	rm -f $(TARGET) *.o

src/et-portaudio/README.md

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+# et-portaudio
+
+A utility program intended for script use to convert a supported
+EmComm Tools ALSA audio device (i.e. `ET_AUDIO`) to a PulseAudio device. 
+
+## Usage
+
+Returns a JSON object with the PulseAudio device details on success.
+
+```bash
+./et-portaudio 2>/dev/null
+{
+  "device": "USB Audio Device: - (hw:1,0)",
+  "index": 6
+}
+```
+
+If no supported device is found or on error, the utility exits with an
+exit status of 1.
+
+
+## Build
+
+``bash
+make
+```

src/et-portaudio/gen-fldigi-cfg.sh

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+#!/bin/bash
+# Author  : Gaston Gonzalez
+# Date    : 1 October 2025
+# Purpose : Temporary script to fast-fail dynamic fldigi config for PnP
+#
+# NOTE:
+#
+# THIS IS JUST USED DURING DEVELOPMENT. AN XML PARSER WILL BE USED TO MODIFY
+# THE FLDIGI CONFIG FOR THE FINAL PNP SOLUTION. SO THAT USER CHANGES CAN STILL
+# BE PERSISTED.
+
+CMD=et-portaudio
+PORT_AUDIO_CONF=conf.tmp
+FLDIGI_CONF_FILE="${HOME}/.fldigi/fldigi_def.xml"
+
+# clean up temporary config that may exist
+[[ -e ${PORT_AUDIO_CONF} ]] && rm ${PORT_AUDIO_CONF}
+
+[[ ! -e ${CMD} ]] && make
+./${CMD} 2>/dev/null > ${PORT_AUDIO_CONF}
+
+if [[ $? -ne 0 ]]; then
+  echo "No supported ET_AUDIO device found"
+  exit 1
+fi
+
+DEVICE=$(jq -r -e '.device' ${PORT_AUDIO_CONF})
+if [[ $? -ne 0 ]]; then
+  echo "Error getting PulseAudio device name for ET_AUDIO device"
+  exit 1
+fi
+
+INDEX=$(jq -r -e '.index' ${PORT_AUDIO_CONF})
+if [[ $? -ne 0 ]]; then
+  echo "Error getting PulseAudio device index for ET_AUDIO device"
+  exit 1
+fi
+
+et-log "Copying fldigi template..."
+cp -v ../../overlay/etc/skel/.fldigi/fldigi_def.xml ~/.fldigi/
+
+et-log "Updating PortAudio devices..."
+sed -i "s|^<AUDIOIO>.*|<AUDIOIO>1</AUDIOIO>|" ${FLDIGI_CONF_FILE}
+
+sed -i "s|^<PORTINDEVICE>.*|<PORTINDEVICE>${DEVICE}</PORTINDEVICE>|" ${FLDIGI_CONF_FILE}
+sed -i "s|^<PORTININDEX>.*|<PORTININDEX>${INDEX}</PORTININDEX>|" ${FLDIGI_CONF_FILE}
+
+sed -i "s|^<PORTOUTDEVICE>.*|<PORTOUTDEVICE>${DEVICE}</PORTOUTDEVICE>|" ${FLDIGI_CONF_FILE}
+sed -i "s|^<PORTOUTINDEX>.*|<PORTOUTINDEX>${INDEX}</PORTOUTINDEX>|" ${FLDIGI_CONF_FILE}

src/et-portaudio/main.c

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+/*
+ * Author  : Gaston Gonzalez
+ * Date    : 1 October 2025
+ * Purpose : Maps an ET_AUDIO ALSA device to a PortAudio device.
+ *
+ * This utility enumerates all ALSA audio devices using PortAudio
+ * to identify a currently plugged-in ET_AUDIO device. If a matching 
+ * device is found, it generates a JSON object on STDOUT containing:
+ *
+ *  - PortAudio device name
+ *  - PortAudio device index
+ *
+ * Exit Status:
+ *   0 - ET_AUDIO device found and JSON output generated successfully
+ *   1 - ET_AUDIO device not found
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "portaudio.h"
+
+#define PROC_ALSA_PATH_FMT "/proc/asound/card%d/id"
+
+// Read the ALSA card ID from the /proc filesystem
+int get_alsa_card_id(int card, char *id_buf, size_t buf_size) {
+    char path[64];
+    snprintf(path, sizeof(path), PROC_ALSA_PATH_FMT, card);
+    FILE *f = fopen(path, "r");
+    if (!f) return -1;
+    if (!fgets(id_buf, buf_size, f)) {
+        fclose(f);
+        return -1;
+    }
+    id_buf[strcspn(id_buf, "\n")] = 0; 
+    fclose(f);
+
+    return 0;
+}
+
+int main(void) {
+    PaError err;
+    int i, numDevices;
+    const PaDeviceInfo *deviceInfo;
+    const PaHostApiInfo *hostApiInfo;
+    int found = 0;  
+
+    err = Pa_Initialize();
+    if (err != paNoError) {
+        fprintf(stderr, "PortAudio error: %s\n", Pa_GetErrorText(err));
+        return 1;
+    }
+
+    numDevices = Pa_GetDeviceCount();
+    if (numDevices < 0) {
+        fprintf(stderr, "No audio devices found");
+        Pa_Terminate();
+        return 1;
+    }
+
+    for (i = 0; i < numDevices; i++) {
+        deviceInfo = Pa_GetDeviceInfo(i);
+        hostApiInfo = Pa_GetHostApiInfo(deviceInfo->hostApi);
+
+        // Only show ALSA devices
+        if (hostApiInfo && strcmp(hostApiInfo->name, "ALSA") == 0) {
+            int card = -1, device = -1;
+
+            // Extract ALSA card and device (hw:X,Y)
+            if (sscanf(deviceInfo->name, "%*[^()](hw:%d,%d)", &card, &device) == 2) {
+                char card_id[64];
+                if (get_alsa_card_id(card, card_id, sizeof(card_id)) == 0) {
+
+                    // Only print if card ID matches ET_AUDIO
+                    if (strcmp(card_id, "ET_AUDIO") == 0) {
+                        found = 1;
+                        printf("{\n");
+                        printf("  \"device\": \"%s\",\n", deviceInfo->name);
+                        printf("  \"index\": %d\n", i);
+                        printf("}\n");
+                    }
+                }
+            }
+        }
+    }
+
+    Pa_Terminate();
+    return found ? 0 : 1;
+}