From c0e1b7e255a43e49517eb324e20a86d7efd48d7f Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Wed, 22 Apr 2026 07:33:42 +0200
Subject: [PATCH] [libretiny] Use xTaskGetTickCount() directly for millis() on
 1 kHz chips

---
 esphome/components/libretiny/core.cpp | 23 ++++++++++++++++++++++-
 esphome/core/millis_internal.h        | 21 ++++++++++++++++++---
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/esphome/components/libretiny/core.cpp b/esphome/components/libretiny/core.cpp
index 1cfe68e924..1d7cb6ff60 100644
--- a/esphome/components/libretiny/core.cpp
+++ b/esphome/components/libretiny/core.cpp
@@ -16,8 +16,29 @@ void loop();
 namespace esphome {
 
 void HOT yield() { ::yield(); }
+// Skip the Arduino core's ::millis() wrapper so the public esphome::millis() is
+// inlinable at its call sites and matches MillisInternal::get()'s fast path.
+// IRAM_ATTR is kept because components (e.g. rotary_encoder) call millis() from
+// ISR handlers; xTaskGetTickCountFromISR() is used in ISR context to satisfy the
+// FreeRTOS API contract.
+//
+// RTL87xx and LN882x run FreeRTOS at 1 kHz, so xTaskGetTickCount() is already in
+// milliseconds. BK72xx runs at 500 Hz — multiply by portTICK_PERIOD_MS (== 2) to
+// convert ticks to milliseconds, matching the Arduino core's wiring.c.
+#if defined(USE_RTL87XX) || defined(USE_LN882X)
+uint32_t IRAM_ATTR HOT millis() {
+  static_assert(configTICK_RATE_HZ == 1000, "millis() fast path requires 1 kHz FreeRTOS tick");
+  return in_isr_context() ? xTaskGetTickCountFromISR() : xTaskGetTickCount();
+}
+#elif defined(USE_BK72XX)
+uint32_t IRAM_ATTR HOT millis() {
+  // BK72xx's Arduino millis() does not dispatch on ISR context; match that.
+  return xTaskGetTickCount() * portTICK_PERIOD_MS;
+}
+#else
 uint32_t IRAM_ATTR HOT millis() { return ::millis(); }
-uint64_t millis_64() { return Millis64Impl::compute(::millis()); }
+#endif
+uint64_t millis_64() { return Millis64Impl::compute(millis()); }
 uint32_t IRAM_ATTR HOT micros() { return ::micros(); }
 void HOT delay(uint32_t ms) { ::delay(ms); }
 void IRAM_ATTR HOT delayMicroseconds(uint32_t us) { ::delayMicroseconds(us); }
diff --git a/esphome/core/millis_internal.h b/esphome/core/millis_internal.h
index 6b73476680..ded49f9cd2 100644
--- a/esphome/core/millis_internal.h
+++ b/esphome/core/millis_internal.h
@@ -7,6 +7,9 @@
 #include <freertos/FreeRTOS.h>
 #include <freertos/task.h>
 #include <sdkconfig.h>
+#elif defined(USE_LIBRETINY)
+#include <FreeRTOS.h>
+#include <task.h>
 #endif
 
 namespace esphome {
@@ -14,10 +17,11 @@ namespace esphome {
 // Friend-gated accessor for a fast millis() variant intended only for
 // known task-context callers on the main loop hot path (Application::loop()
 // and WarnIfComponentBlockingGuard::finish()). It skips the ISR-context
-// dispatch that the public esphome::millis() pays on ESP32.
+// dispatch that the public esphome::millis() pays on ESP32 and libretiny.
 //
-// MUST NOT be called from ISR context: on ESP32 it calls the non-FromISR
-// FreeRTOS API directly, which is undefined behavior in ISR context.
+// MUST NOT be called from ISR context: on ESP32 and libretiny it calls the
+// non-FromISR FreeRTOS API directly, which is undefined behavior in ISR
+// context.
 //
 // Adding new callers requires adding a friend declaration here — that
 // is the review point. Do not relax the access (e.g. by making get()
@@ -31,6 +35,17 @@ class MillisInternal {
   static ESPHOME_ALWAYS_INLINE uint32_t get() {
 #if defined(USE_ESP32) && CONFIG_FREERTOS_HZ == 1000
     return xTaskGetTickCount();
+#elif defined(USE_LIBRETINY) && (defined(USE_RTL87XX) || defined(USE_LN882X))
+    // RTL87xx and LN882x run FreeRTOS at 1 kHz, so xTaskGetTickCount() is
+    // already in milliseconds.
+    static_assert(configTICK_RATE_HZ == 1000, "MillisInternal fast path requires 1 kHz FreeRTOS tick");
+    return xTaskGetTickCount();
+#elif defined(USE_BK72XX)
+    // BK72xx runs FreeRTOS at 500 Hz; scale ticks by portTICK_PERIOD_MS (== 2).
+    // Inlined here because esphome::millis() on BK72xx has no-op IRAM_ATTR but
+    // is still out-of-line, so calling it would cost a real function call.
+    static_assert(configTICK_RATE_HZ == 500, "BK72xx MillisInternal assumes 500 Hz FreeRTOS tick");
+    return xTaskGetTickCount() * portTICK_PERIOD_MS;
 #else
     return millis();
 #endif