From 43cd92f3bbd214d8dfc83358ad37d585eeeb32e1 Mon Sep 17 00:00:00 2001
From: Simon Kueppers <simon.kueppers@skueppers.de>
Date: Sun, 21 May 2023 13:56:14 +0200
Subject: [PATCH] Added functionality to send back HID button presses to host

---
 stm32/aioc-fw/Src/usb_hid.c | 14 +++++++++++---
 stm32/aioc-fw/Src/usb_hid.h |  9 +++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/stm32/aioc-fw/Src/usb_hid.c b/stm32/aioc-fw/Src/usb_hid.c
index dc23053..97c932d 100644
--- a/stm32/aioc-fw/Src/usb_hid.c
+++ b/stm32/aioc-fw/Src/usb_hid.c
@@ -6,23 +6,24 @@
 
 #define USB_HID_INOUT_REPORT_LEN  4
 
+static uint8_t buttonState = 0x00;
 static uint8_t gpioState = 0x00;
 
 static void MakeReport(uint8_t * buffer)
 {
     /* TODO: Read the actual states of the GPIO input hardware pins. */
-    buffer[0] = 0x00;
+    buffer[0] = buttonState & 0x0F;
     buffer[1] = gpioState;
     buffer[2] = 0x00;
     buffer[3] = 0x00;
 }
 
-static void SendReport(void)
+static bool SendReport(void)
 {
     uint8_t reportBuffer[USB_HID_INOUT_REPORT_LEN];
     MakeReport(reportBuffer);
 
-    tud_hid_report(0, reportBuffer, sizeof(reportBuffer));
+    return tud_hid_report(0, reportBuffer, sizeof(reportBuffer));
 }
 
 static void ControlPTT(uint8_t gpio)
@@ -160,3 +161,10 @@ void USB_HIDInit(void)
 
 
 }
+
+bool USB_HIDSendButtonState(uint8_t buttonMask)
+{
+    buttonState = buttonMask;
+
+    return SendReport();
+}
diff --git a/stm32/aioc-fw/Src/usb_hid.h b/stm32/aioc-fw/Src/usb_hid.h
index 661cf20..817cd7d 100644
--- a/stm32/aioc-fw/Src/usb_hid.h
+++ b/stm32/aioc-fw/Src/usb_hid.h
@@ -1,6 +1,15 @@
 #ifndef USB_HID_H_
 #define USB_HID_H_
 
+#include <stdint.h>
+#include <stdbool.h>
+
+#define USB_HID_BUTTON_VOLUP    0x01
+#define USB_HID_BUTTON_VOLDN    0x02
+#define USB_HID_BUTTON_PLAYMUTE 0x04
+#define USB_HID_BUTTON_RECMUTE  0x08
+
 void USB_HIDInit(void);
+bool USB_HIDSendButtonState(uint8_t inputsMask);
 
 #endif /* USB_HID_H_ */