update(gamepad): update xinput report and desc

Signed-off-by: sakumisu <1203593632@qq.com>

Author: sakumisu

class/gamepad/usb_gamepad.h

@@ -143,12 +143,12 @@ struct xinput_out_report {
 } __PACKED;
 
 // clang-format off
-#define XINPUT_DESCRIPTOR_LEN (9 + 16 + 7 + 7)
+#define XINPUT_DESCRIPTOR_LEN (9 + 17 + 7 + 7)
 
 #define XINPUT_DESCRIPTOR_INIT(bInterfaceNumber, out_ep, in_ep)                                                                     \
     USB_INTERFACE_DESCRIPTOR_INIT(bInterfaceNumber, 0x00, 0x02, 0xff, 0x5d, 0x01, 0x00), /* XInput proprietary descriptor (0x21) */ \
-    16, 0x21, 0x00, 0x01, 0x01, 0x24, in_ep, 0x14, 0x03, 0x00, 0x03, 0x13, out_ep, 0x00, 0x03, 0x00,                               \
-    USB_ENDPOINT_DESCRIPTOR_INIT(in_ep, 0x03, 32, 0x01),                                                                        \
+    0x11, 0x21, 0x00, 0x01, 0x01, 0x25, in_ep, 0x14, 0x00, 0x00, 0x00, 0x00, 0x13, out_ep, 0x08, 0x00, 0x00,                        \
+    USB_ENDPOINT_DESCRIPTOR_INIT(in_ep, 0x03, 32, 0x01),                                                                            \
     USB_ENDPOINT_DESCRIPTOR_INIT(out_ep, 0x03, 32, 0x08)
 // clang-format on
 

class/gamepad/usbd_gamepad.c

@@ -21,6 +21,24 @@ static int xinput_vendor_class_request_handler(uint8_t busid, struct usb_setup_p
     return 0;
 }
 
+// Convert analog value from Joypad (0-255, center 128) to signed 16-bit
+static int16_t convert_axis_to_s16(uint8_t value)
+{
+    int32_t scaled = ((int32_t)value - 128) * 256;
+    if (scaled < -32768) scaled = -32768;
+    if (scaled > 32767) scaled = 32767;
+    return (int16_t)scaled;
+}
+
+// Convert and invert axis (for Y-axis where convention differs)
+static int16_t convert_axis_to_s16_inverted(uint8_t value)
+{
+    int32_t scaled = -((int32_t)value - 128) * 256;
+    if (scaled < -32768) scaled = -32768;
+    if (scaled > 32767) scaled = 32767;
+    return (int16_t)scaled;
+}
+
 int usbd_gamepad_xinput_send_report(uint8_t ep, struct usb_gamepad_report *report)
 {
     struct xinput_in_report *xinput_report;
@@ -68,6 +86,13 @@ int usbd_gamepad_xinput_send_report(uint8_t ep, struct usb_gamepad_report *repor
     if (xinput_report->rt == 0 && (report->buttons & USB_GAMEPAD_BUTTON_R2))
         xinput_report->rt = 0xFF;
 
+    // Analog sticks (signed 16-bit, -32768 to +32767)
+    // Y-axis inverted: input 0=down, XInput convention positive=up
+    xinput_report->lx = convert_axis_to_s16(report->lx);
+    xinput_report->ly = convert_axis_to_s16_inverted(report->ly);
+    xinput_report->rx = convert_axis_to_s16(report->rx);
+    xinput_report->ry = convert_axis_to_s16_inverted(report->ry);
+
     return usbd_ep_start_write(0, ep, gamepad_report_buffer, sizeof(struct xinput_in_report));
 }
 

demo/gamepad_template.c

@@ -89,7 +89,7 @@ static const uint8_t *device_quality_descriptor_callback(uint8_t speed)
 
 static const char *string_descriptor_callback(uint8_t speed, uint8_t index)
 {
-    if (index >= (sizeof(string_descriptors) / sizeof(char *))) {
+    if (index >= 4) {
         return NULL;
     }