Bluetooth: audio: Add initial Hearing Access Service implementation

This adds bare minimum implementation of Hearing Access Service.
The GATT HAS service contains one Hearing Aid Features mandatory
characteristic.

Signed-off-by: Mariusz Skamra <mariusz.skamra@codecoup.pl>

subsys/bluetooth/audio/CMakeLists.txt

@@ -50,3 +50,4 @@ zephyr_library_sources_ifdef(CONFIG_BT_AUDIO_BROADCAST_SOURCE broadcast_source.c
 zephyr_library_sources_ifdef(CONFIG_BT_AUDIO_BROADCAST_SINK broadcast_sink.c)
 zephyr_library_sources_ifdef(CONFIG_BT_BASS bass.c)
 zephyr_library_sources_ifdef(CONFIG_BT_BASS_CLIENT bass_client.c)
+zephyr_library_sources_ifdef(CONFIG_BT_HAS has.c)

subsys/bluetooth/audio/Kconfig

@@ -33,5 +33,6 @@ rsource "Kconfig.mics"
 rsource "Kconfig.csis"
 rsource "Kconfig.mcs"
 rsource "Kconfig.bass"
+rsource "Kconfig.has"
 
 endif # BT_AUDIO

subsys/bluetooth/audio/Kconfig.has

@@ -0,0 +1,63 @@
+# Bluetooth Audio - Hearing Access Service options
+#
+# Copyright (c) 2022 Codecoup
+#
+# SPDX-License-Identifier: Apache-2.0
+
+config BT_HAS
+	bool "Hearing Access Service support [EXPERIMENTAL]"
+	select EXPERIMENTAL
+	help
+	  This option enables support for Hearing Access Service.
+
+if BT_HAS
+
+choice BT_HAS_HEARING_AID_TYPE_CHOICE
+	prompt "Hearing Aid Type selection"
+	help
+	  Select the Hearing Aid Type to compile.
+
+config BT_HAS_HEARING_AID_MONAURAL
+	bool "Monaural Hearing Aid"
+
+config BT_HAS_HEARING_AID_BINAURAL
+	depends on BT_CSIS
+	bool "Binaural Hearing Aid"
+
+config BT_HAS_HEARING_AID_BANDED
+	bool "Banded Hearing Aid"
+
+endchoice # BT_HAS_HEARING_AID_TYPE_CHOICE
+
+if BT_HAS_HEARING_AID_MONAURAL || BT_HAS_HEARING_AID_BINAURAL
+
+choice BT_HAS_HEARING_AID_LOCATION
+	prompt "Hearing Aid Device Location"
+	help
+	  Select the Hearing Aid Device location.
+
+config BT_HAS_HEARING_AID_LEFT
+	bool "Left Ear"
+
+config BT_HAS_HEARING_AID_RIGHT
+	bool "Right Ear"
+
+endchoice # BT_HAS_HEARING_AID_LOCATION
+
+endif # BT_HAS_HEARING_AID_MONAURAL || BT_HAS_HEARING_AID_BINAURAL
+
+config BT_HAS_HEARING_AID_TYPE
+	int # hidden
+	range 0 2
+	default 0 if BT_HAS_HEARING_AID_BINAURAL
+	default 1 if BT_HAS_HEARING_AID_MONAURAL
+	default 2 if BT_HAS_HEARING_AID_BANDED
+	help
+	  The value shall be one of 3 defined by the HAS 1.0 specification table 3.2
+
+config BT_DEBUG_HAS
+	bool "Hearing Access Service debug"
+	help
+	  This option enables enables Hearing Access Service debug logs.
+
+endif # BT_HAS

subsys/bluetooth/audio/has.c

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2022 Codecoup
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr.h>
+
+#include <device.h>
+
+#include <bluetooth/bluetooth.h>
+#include <bluetooth/gatt.h>
+#include <bluetooth/audio/audio.h>
+#include <bluetooth/audio/capabilities.h>
+
+#include "has_internal.h"
+
+#define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_HAS)
+#define LOG_MODULE_NAME bt_has
+#include "common/log.h"
+
+static struct bt_has has;
+
+static ssize_t read_features(struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf,
+			     uint16_t len, uint16_t offset)
+{
+	BT_DBG("conn %p attr %p offset %d", conn, attr, offset);
+
+	if (offset > sizeof(has.features)) {
+		return BT_GATT_ERR(BT_ATT_ERR_INVALID_OFFSET);
+	}
+
+	return bt_gatt_attr_read(conn, attr, buf, len, offset, &has.features,
+				 sizeof(has.features));
+}
+
+/* Hearing Access Service GATT Attributes */
+BT_GATT_SERVICE_DEFINE(has_svc,
+	BT_GATT_PRIMARY_SERVICE(BT_UUID_HAS),
+	BT_GATT_CHARACTERISTIC(BT_UUID_HAS_HEARING_AID_FEATURES, BT_GATT_CHRC_READ,
+			       BT_GATT_PERM_READ_ENCRYPT, read_features, NULL, NULL),
+);
+
+static int has_init(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+
+	/* Initialize the supported features characteristic value */
+	has.features = CONFIG_BT_HAS_HEARING_AID_TYPE & BT_HAS_FEAT_HEARING_AID_TYPE_MASK;
+
+	if (IS_ENABLED(CONFIG_BT_HAS_HEARING_AID_BANDED)) {
+		/* HAP_d1.0r00; 3.7 BAP Unicast Server role requirements
+		 * A Banded Hearing Aid in the HA role shall set the Front Left and the Front
+		 * Right bits to a value of 0b1 in the Sink Audio Locations characteristic value.
+		 */
+		bt_audio_capability_set_location(BT_AUDIO_SINK, BT_AUDIO_LOCATION_FRONT_LEFT |
+								BT_AUDIO_LOCATION_FRONT_RIGHT);
+	} else if (IS_ENABLED(CONFIG_BT_HAS_HEARING_AID_LEFT)) {
+		bt_audio_capability_set_location(BT_AUDIO_SINK, BT_AUDIO_LOCATION_FRONT_LEFT);
+	} else {
+		bt_audio_capability_set_location(BT_AUDIO_SINK, BT_AUDIO_LOCATION_FRONT_RIGHT);
+	}
+
+	return 0;
+}
+
+SYS_INIT(has_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);

subsys/bluetooth/audio/has_internal.h

@@ -0,0 +1,16 @@
+/** @file
+ *  @brief Internal APIs for Bluetooth Hearing Access Profile.
+ */
+
+/*
+ * Copyright (c) 2022 Codecoup
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define BT_HAS_FEAT_HEARING_AID_TYPE_MASK 0x03
+
+struct bt_has {
+	/** Hearing Aid Features value */
+	uint8_t features;
+};