meta-digi-dey: pulseaudio: improve HDMI hotplug script

The HDMI hotplug script required alsa-utils to be installed in order to work.
This commit avoids this by adding a recipe for a small binary that replaces
aplay in the script.

https://jira.digi.com/browse/DEL-3482

Signed-off-by: Gabriel Valcazar <gabriel.valcazar@digi.com>

meta-digi-dey/recipes-multimedia/alsa/card-detect.bb

@@ -0,0 +1,21 @@
+# Copyright (C) 2017 Digi International.
+
+SUMMARY = "DEY sound card detection app"
+SECTION = "multimedia"
+LICENSE = "MPL-2.0"
+LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/MPL-2.0;md5=815ca599c9df247a0c7f619bab123dad"
+
+DEPENDS = "alsa-lib"
+
+SRC_URI = "file://card-detect.c"
+
+S = "${WORKDIR}"
+
+do_compile() {
+	${CC} -O2 -Wall card-detect.c -o card-detect -lasound
+}
+
+do_install() {
+	install -d ${D}${bindir}
+	install -m 0755 card-detect ${D}${bindir}
+}

meta-digi-dey/recipes-multimedia/alsa/card-detect/card-detect.c

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2017 Digi International Inc.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <alsa/asoundlib.h>
+
+int main(int argc, char *argv[])
+{
+	int len, ret = EXIT_SUCCESS;
+	snd_pcm_t *handle;
+	char *device;
+
+	if (argc < 2) {
+		printf("Usage: %s [CARD NUMBER]\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	len = strlen("hw:") + strlen(argv[1]) + 1;
+	device = calloc(1, len);
+	snprintf(device, len, "hw:%s", argv[1]);
+
+	/* Open the PCM-device in playback mode */
+	if (snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, 0) < 0) {
+		printf("Could't open PCM '%s'\n", device);
+		ret = EXIT_FAILURE;
+	} else {
+		printf("Device %s opened successfully\n", device);
+		snd_pcm_close(handle);
+	}
+
+	free(device);
+	return ret;
+}

meta-digi-dey/recipes-multimedia/packagegroups/packagegroup-dey-audio.bb

@@ -22,3 +22,5 @@ RDEPENDS_${PN} = "\
     alsa-states \
     ${ALSA_UTILS_PKGS} \
 "
+
+RDEPENDS_${PN}_append_ccimx6sbc = " card-detect"

meta-digi-dey/recipes-multimedia/pulseaudio/pulseaudio/hdmi_hotplug.sh

@@ -27,15 +27,7 @@ done
 # HDMI audio sink from ALSA
 if [ "${EVENT}" = "plugin" ]; then
 	if ! pactl list sinks | grep -qs "imx-hdmi-soc"; then
-		if which aplay; then
+		card-detect "${HDMI_CARD}"
-			# Run a command that always fails but loads
-			# pulseaudio HDMI sink/card as a side effect
-			aplay / -D "hw:${HDMI_CARD}"
- 		else
-			# Unload and reload the detection module
-			pactl unload-module module-udev-detect
-			pactl load-module module-udev-detect tsched=0
-		fi
 
 		# Set HDMI as default sink
 		pactl set-default-sink "$(pactl list sinks | grep -i 'Name:.*hdmi' | cut -d ' ' -f2)"

meta-digi-dey/recipes-multimedia/pulseaudio/pulseaudio_%.bbappend

@@ -16,3 +16,6 @@ do_install_append_ccimx6sbc() {
 }
 
 PACKAGE_ARCH = "${MACHINE_ARCH}"
+
+# The card-detect binary is only necessary for the HDMI hotplug to work on the ccimx6sbc
+RDEPENDS_${PN}_append_ccimx6sbc = " card-detect"