From 9e647f9a46c2322adb9c8c6fe90f973114474c83 Mon Sep 17 00:00:00 2001
From: Mario Kleiner <mario.kleiner.de@gmail.com>
Date: Thu, 13 Apr 2023 22:29:28 +0200
Subject: [PATCH] d/vive: Parse/Recognize HTC Vive Pro Eye HMD headphone audio
 buttons.

Does not do anything yet within Monado, but documents how to parse
button state of left headphone volume up/down buttons and right
headphone microphone mute button.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
---
 src/xrt/drivers/vive/vive_device.c   | 7 +++++++
 src/xrt/drivers/vive/vive_device.h   | 1 +
 src/xrt/drivers/vive/vive_protocol.h | 3 ++-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/xrt/drivers/vive/vive_device.c b/src/xrt/drivers/vive/vive_device.c
index 7a757843d..8e5df1ee2 100644
--- a/src/xrt/drivers/vive/vive_device.c
+++ b/src/xrt/drivers/vive/vive_device.c
@@ -288,10 +288,17 @@ vive_mainboard_decode_message(struct vive_device *d, struct vive_mainboard_statu
 		d->board.proximity = proximity;
 	}
 
+	/* System button on HMD */
 	if (d->board.button != report->button) {
 		d->board.button = report->button;
 		VIVE_TRACE(d, "Button %d.", report->button);
 	}
+
+	/* Vive Pro headphone buttons, reported mutually exclusive: 1 = Volume up, 2 = Volume down, 4 = Mic mute */
+	if (d->board.audio_button != report->audio_button) {
+		d->board.audio_button = report->audio_button;
+		VIVE_TRACE(d, "Audio button %d.", report->audio_button);
+	}
 }
 
 static inline int
diff --git a/src/xrt/drivers/vive/vive_device.h b/src/xrt/drivers/vive/vive_device.h
index 96b6dbff9..760f97826 100644
--- a/src/xrt/drivers/vive/vive_device.h
+++ b/src/xrt/drivers/vive/vive_device.h
@@ -56,6 +56,7 @@ struct vive_device
 		uint16_t lens_separation;
 		uint16_t proximity;
 		uint8_t button;
+		uint8_t audio_button;
 	} board;
 
 	enum u_logging_level log_level;
diff --git a/src/xrt/drivers/vive/vive_protocol.h b/src/xrt/drivers/vive/vive_protocol.h
index 665a5bea1..069140a6f 100644
--- a/src/xrt/drivers/vive/vive_protocol.h
+++ b/src/xrt/drivers/vive/vive_protocol.h
@@ -87,7 +87,8 @@ struct vive_mainboard_status_report
 	uint16_t lens_separation;
 	uint16_t reserved1;
 	uint8_t button;
-	uint8_t reserved2[3];
+	uint8_t audio_button;
+	uint8_t reserved2[2];
 	uint8_t proximity_change;
 	uint8_t reserved3;
 	uint16_t proximity;