ws2812: support thingplus-rp2040 board

  Added 125 MHz rp2040 timing
  Added unsafe.Pointer for pointer conversion

Author: oflebbe

examples/ws2812/others.go

@@ -1,5 +1,5 @@
-//go:build !digispark && !arduino && !qtpy && !m5stamp_c3
-// +build !digispark,!arduino,!qtpy,!m5stamp_c3
+//go:build !digispark && !arduino && !qtpy && !m5stamp_c3 && !thingplus_rp2040
+// +build !digispark,!arduino,!qtpy,!m5stamp_c3,!thingplus_rp2040
 
 package main
 

examples/ws2812/thingplus-rp2040.go

@@ -0,0 +1,13 @@
+//go:build thingplus_rp2040
+// +build thingplus_rp2040
+
+package main
+
+import "machine"
+
+// This is the pin assignment for the internal neopixel of the
+// Sparkfun thingplus rp2040.
+// Replace neo and led in the code below to match the pin
+// that you are using if different.
+var neo machine.Pin = machine.GPIO8
+var led = machine.LED

ws2812/gen-ws2812.go

@@ -252,7 +252,7 @@ func writeGoWrapper(f *os.File, arch string, megahertz int) error {
 	fmt.Fprintf(buf, "	portClear, maskClear := d.Pin.PortMaskClear()\n")
 	fmt.Fprintf(buf, "\n")
 	fmt.Fprintf(buf, "	mask := interrupt.Disable()\n")
-	fmt.Fprintf(buf, "	C.ws2812_writeByte%d(C.char(c), portSet, portClear, maskSet, maskClear)\n", megahertz)
+	fmt.Fprintf(buf, "	C.ws2812_writeByte%d(C.char(c), (*uint32)(unsafe.Pointer(portSet)), (*uint32)(unsafe.Pointer(portClear)), maskSet, maskClear)\n", megahertz)
 	buf.WriteString(`
 	interrupt.Restore(mask)
 }
@@ -293,6 +293,7 @@ package ws2812
 // gen-ws2812.go and run "go generate".
 
 import "runtime/interrupt"
+import "unsafe"
 
 /*
 #include <stdint.h>