ws2812: fix build on ESP32-S3

ws2812/ws2812_freq_esp32s3.go

@@ -0,0 +1,13 @@
+//go:build esp32s3
+
+package ws2812
+
+import "machine"
+
+// cpuFrequency returns the current CPU frequency in Hz on the ESP32-S3, which
+// supports runtime frequency scaling and exposes GetCPUFrequency() instead of
+// the constant-style CPUFrequency().
+func cpuFrequency() uint32 {
+	f, _ := machine.GetCPUFrequency()
+	return f
+}

ws2812/ws2812_freq_xtensa.go

@@ -0,0 +1,11 @@
+//go:build xtensa && !esp32s3
+
+package ws2812
+
+import "machine"
+
+// cpuFrequency returns the current CPU frequency in Hz on Xtensa targets that
+// expose the constant-style machine.CPUFrequency() (e.g. the original ESP32).
+func cpuFrequency() uint32 {
+	return machine.CPUFrequency()
+}

ws2812/ws2812_xtensa.go

@@ -4,7 +4,6 @@ package ws2812
 
 import (
 	"device"
-	"machine"
 	"runtime/interrupt"
 	"unsafe"
 )
@@ -14,7 +13,7 @@ func (d Device) WriteByte(c byte) error {
 	portClear, maskClear := d.Pin.PortMaskClear()
 	mask := interrupt.Disable()
 
-	switch machine.CPUFrequency() {
+	switch cpuFrequency() {
 	case 160e6: // 160MHz
 		// See:
 		// https://wp.josh.com/2014/05/13/ws2812-neopixels-are-not-so-finicky-once-you-get-to-know-them/