Added LED toggling from the Rosalina misc. menu

sysmodules/rosalina/source/mcu.c

@@ -0,0 +1,42 @@
+#include "mcu.h"
+
+Result mcuInit(void)
+{
+    return srvGetServiceHandle(&mcuhwcHandle, "mcu::HWC");
+}
+
+Result mcuExit(void)
+{
+    return svcCloseHandle(mcuhwcHandle);
+}
+
+Result mcuReadRegister(u8 reg, u8* data, u32 size)
+{
+    u32* ipc = getThreadCommandBuffer();
+    ipc[0] = 0x10082;
+    ipc[1] = reg;
+    ipc[2] = size;
+    ipc[3] = size << 4 | 0xC;
+    ipc[4] = (u32)data;
+    Result ret = svcSendSyncRequest(mcuhwcHandle);
+    if(ret < 0) return ret;
+    return ipc[1];
+}
+
+Result mcuWriteRegister(u8 reg, u8* data, u32 size)
+{
+    u32* ipc = getThreadCommandBuffer();
+    ipc[0] = 0x20082;
+    ipc[1] = reg;
+    ipc[2] = size;
+    ipc[3] = size << 4 | 0xA;
+    ipc[4] = (u32)data;
+    Result ret = svcSendSyncRequest(mcuhwcHandle);
+    if(ret < 0) return ret;
+    return ipc[1];
+}
+
+Result mcuGetLEDState(u8* out)
+{
+  return mcuReadRegister(0x28, out, 1);
+}