Beginning support USB for Nintendo Switch...

It shows up with name XBox360 for Windows (at least the version I have)...

But at least it is starting to give some data

USBHost_t36.h

 // your best effort to read chapter 4 before asking USB questions!
 
 
-//#define USBHOST_PRINT_DEBUG
+#define USBHOST_PRINT_DEBUG
 //#define USBHDBGSerial	Serial1
 
 #ifndef USBHDBGSerial
     bool setLEDs(uint8_t lr, uint8_t lg, uint8_t lb);  // sets Leds, 
     bool inline setLEDs(uint32_t leds) {return setLEDs((leds >> 16) & 0xff, (leds >> 8) & 0xff, leds & 0xff);}  // sets Leds - passing one arg for all leds 
 	enum { STANDARD_AXIS_COUNT = 10, ADDITIONAL_AXIS_COUNT = 54, TOTAL_AXIS_COUNT = (STANDARD_AXIS_COUNT+ADDITIONAL_AXIS_COUNT) };
-	typedef enum { UNKNOWN=0, PS3, PS4, XBOXONE, XBOX360, PS3_MOTION, SpaceNav} joytype_t;
+	typedef enum { UNKNOWN=0, PS3, PS4, XBOXONE, XBOX360, PS3_MOTION, SpaceNav, SWITCH} joytype_t;
 	joytype_t joystickType() {return joystickType_;} 
 
 	// PS3 pair function. hack, requires that it be connect4ed by USB and we have the address of the Bluetooth dongle...

bluetooth.cpp

 #define println USBHost::println_//#define DEBUG_BT
 
 #define DEBUG_BT
-#define DEBUG_BT_VERBOSE
+//#define DEBUG_BT_VERBOSE
 
 #ifndef DEBUG_BT
 #undef DEBUG_BT_VERBOSE

examples/USBHost_viewer/USBHost_viewer.ino

 //
 // This example is in the public domain
 //=============================================================================
-#define USE_ST77XX // define this if you wish to use one of these displays.
+//#define USE_ST77XX // define this if you wish to use one of these displays.
 
 #include "USBHost_t36.h"
 
 
       case JoystickController::XBOXONE:
       case JoystickController::XBOX360:
+      case JoystickController::SWITCH:
         ltv = joystick.getAxis(4);
         rtv = joystick.getAxis(5);
         if ((ltv != joystick_left_trigger_value) || (rtv != joystick_right_trigger_value)) {
   tft.print(top, HEX);
   tft.print(") key release:");
   tft.println(key, HEX);
-}
+}

joystick.cpp

 JoystickController::product_vendor_mapping_t JoystickController::pid_vid_mapping[] = {
 	{ 0x045e, 0x02ea, XBOXONE, false },{ 0x045e, 0x02dd, XBOXONE, false },
 	{ 0x045e, 0x0719, XBOX360, false},
-	{ 0x045e, 0x028E, XBOX360, false},  // Switch? 
+	{ 0x045e, 0x028E, SWITCH, false},  // Switch? 
 	{ 0x054C, 0x0268, PS3, true}, 
 	{ 0x054C, 0x042F, PS3, true},	// PS3 Navigation controller
 	{ 0x054C, 0x03D5, PS3_MOTION, true},	// PS3 Motion controller
 	int16_t	axis[4];
 } xbox360data_t;
 
+typedef struct {
+	uint8_t state;
+	uint8_t id_or_type;
+	// From online references button order: 
+	//     sync, dummy, start, back, a, b, x, y
+	//     dpad up, down left, right
+	//	   lb, rb, left stick, right stick
+	// Axis: 
+	//     lt, rt, lx, ly, rx, ry
+	//
+	uint16_t buttons; 
+	uint8_t lt;
+	uint8_t rt;
+	int16_t	axis[4];
+} switchdataUSB_t;
+
 static const uint8_t xbox_axis_order_mapping[] = {3, 4, 0, 1, 2, 5};
 
 void JoystickController::rx_data(const Transfer_t *transfer)
 {
+	#ifdef  DEBUG_JOYSTICK
 	print("JoystickController::rx_data (", joystickType_, DEC);
 	print("): ");
 	print_hexbytes((uint8_t*)transfer->buffer, transfer->length);
+	#endif
 
 	if (joystickType_ == XBOXONE) {
 		// Process XBOX One data
 
 			if (anychange) joystickEvent = true;
 		}
+	} else if (joystickType_ == SWITCH) {
+		switchdataUSB_t  *switchd = (switchdataUSB_t *)transfer->buffer;
+        if (buttons != switchd->buttons) {
+        	buttons = switchd->buttons;
+        	anychange = true;
+        }
+		axis_mask_ = 0x3f;	
+		axis_changed_mask_ = 0;	// assume none for now
+
+		for (uint8_t i = 0; i < 4; i++) {
+			if (axis[i] != switchd->axis[i]) {
+				axis[i] = switchd->axis[i];
+				axis_changed_mask_ |= (1 << i);
+				anychange = true;
+			}
+		}
+		// the two triggers show up as 4 and 5
+		if (axis[4] != switchd->lt) {
+			axis[4] = switchd->lt;
+			axis_changed_mask_ |= (1 << 4);
+			anychange = true;
+		}
+
+		if (axis[5] != switchd->rt) {
+			axis[5] = switchd->rt;
+			axis_changed_mask_ |= (1 << 5);
+			anychange = true;
+		}
+
+		if (anychange) joystickEvent = true;
 	}
 
 	queue_Data_Transfer(rxpipe_, rxbuf_, rx_size_, this);

keywords.txt

 PS4	LITERAL1
 XBOXONE	LITERAL1
 XBOX360	LITERAL1
-
+SWITCH	LITERAL1
 # USBSerial
 USBHOST_SERIAL_7E1	LITERAL1
 USBHOST_SERIAL_7O1	LITERAL1