From 497f57d0be7988a1dcdc3548e6ed4961e78f672d Mon Sep 17 00:00:00 2001
From: Tomek <tomek@japko.info>
Date: Sat, 15 Aug 2026 14:17:29 +0200
Subject: [PATCH] ws2812: fix build on ESP32-S3

The ESP32-S3 machine package supports runtime CPU frequency scaling and
exposes machine.GetCPUFrequency() instead of the constant-style
machine.CPUFrequency(), so the xtensa WS2812 driver failed to build for
esp32s3 targets with:

    ws2812/ws2812_xtensa.go:17:17: undefined: machine.CPUFrequency

Route the frequency lookup through a small build-tagged cpuFrequency()
helper: xtensa chips with the constant-style API keep using
machine.CPUFrequency(), while the ESP32-S3 uses GetCPUFrequency().

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 ws2812/ws2812_freq_esp32s3.go | 13 +++++++++++++
 ws2812/ws2812_freq_xtensa.go  | 11 +++++++++++
 ws2812/ws2812_xtensa.go       |  3 +--
 3 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 ws2812/ws2812_freq_esp32s3.go
 create mode 100644 ws2812/ws2812_freq_xtensa.go

diff --git a/ws2812/ws2812_freq_esp32s3.go b/ws2812/ws2812_freq_esp32s3.go
new file mode 100644
index 000000000..b3c6ea724
--- /dev/null
+++ b/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
+}
diff --git a/ws2812/ws2812_freq_xtensa.go b/ws2812/ws2812_freq_xtensa.go
new file mode 100644
index 000000000..5d906600e
--- /dev/null
+++ b/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()
+}
diff --git a/ws2812/ws2812_xtensa.go b/ws2812/ws2812_xtensa.go
index a1af02348..a0c89e504 100644
--- a/ws2812/ws2812_xtensa.go
+++ b/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/