avr: Add initial support for atmega32u4 chips

Signed-off-by: Trevor Jones <trevorjones141@gmail.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/avr/Kconfig

@@ -26,6 +26,8 @@ choice
         bool "at90usb1286"
     config MACH_at90usb646
         bool "at90usb646"
+    config MACH_atmega32u4
+        bool "atmega32u4"
     config MACH_atmega1284p
         bool "atmega1284p"
     config MACH_atmega644p
@@ -47,14 +49,14 @@ config MCU
     default "atmega644p" if MACH_atmega644p
     default "at90usb1286" if MACH_at90usb1286
     default "at90usb646" if MACH_at90usb646
+    default "atmega32u4" if MACH_atmega32u4
     default "atmega1280" if MACH_atmega1280
     default "atmega2560" if MACH_atmega2560
 
 config AVRDUDE_PROTOCOL
     string
     default "wiring" if MACH_atmega2560
-    default "avr109" if MACH_at90usb1286
-    default "avr109" if MACH_at90usb646
+    default "avr109" if MACH_at90usb1286 || MACH_at90usb646 || MACH_atmega32u4
     default "arduino"
 
 choice
@@ -76,7 +78,7 @@ config CLOCK_FREQ
 
 config CLEAR_PRESCALER
     bool "Manually clear the CPU prescaler field at startup"
-    depends on MACH_at90usb1286 || MACH_at90usb646
+    depends on MACH_at90usb1286 || MACH_at90usb646 || MACH_atmega32u4
     default y
     help
          Some AVR chips ship with a "clock prescaler" that causes the
@@ -98,7 +100,7 @@ config AVR_WATCHDOG
     default y
 config AVR_USBSERIAL
     bool "Use USB for communication (instead of serial)"
-    depends on MACH_at90usb1286 || MACH_at90usb646
+    depends on MACH_at90usb1286 || MACH_at90usb646 || MACH_atmega32u4
     default y
 config AVR_SERIAL
     depends on !AVR_USBSERIAL
@@ -132,7 +134,7 @@ config SERIAL_PORT
     int
     default 3 if AVR_SERIAL_UART3
     default 2 if AVR_SERIAL_UART2
-    default 1 if MACH_at90usb1286 || MACH_at90usb646 || AVR_SERIAL_UART1
+    default 1 if MACH_at90usb1286 || MACH_at90usb646 || MACH_atmega32u4 || AVR_SERIAL_UART1
     default 0
 
 config SIMULAVR