From 3f7e45fb1bd79409a5718b269b497eaea1b361f5 Mon Sep 17 00:00:00 2001
From: Oleg Kalachev <okalachev@gmail.com>
Date: Tue, 25 Aug 2026 22:31:46 +0300
Subject: [PATCH] Add experimental build for esp32-s31

---
 .github/workflows/build.yml | 22 ++++++++++++++++++++++
 flix/power.ino              |  4 ++++
 2 files changed, 26 insertions(+)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 743662c..056a5e8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -38,6 +38,28 @@ jobs:
     - name: Check c_cpp_properties.json
       run: tools/check_c_cpp_properties.py
 
+  build_linux_s31:
+    runs-on: ubuntu-latest
+    env:
+        ARDUINO_SKETCH_ALWAYS_EXPORT_BINARIES: 1
+    steps:
+    - uses: actions/checkout@v7
+    - name: Install Arduino CLI
+      run: curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | BINDIR=/usr/local/bin sh
+    - name: Install Arduino ESP32 core from idf-release/v6.1
+      run: |
+        mkdir -p ~/Arduino/hardware/espressif
+        git clone --depth 1 --branch idf-release/v6.1 --recursive https://github.com/espressif/arduino-esp32.git ~/Arduino/hardware/espressif/esp32
+        python3 ~/Arduino/hardware/espressif/esp32/tools/get.py
+        touch .core
+    - name: Build firmware for ESP32-S31
+      run: make BOARD=espressif:esp32:esp32s31
+    - name: Upload binaries
+      uses: actions/upload-artifact@v7
+      with:
+        name: firmware-binary-s31
+        path: flix/build
+
   build_macos:
     runs-on: macos-latest
     steps:
diff --git a/flix/power.ino b/flix/power.ino
index 0dcc17e..906bc09 100644
--- a/flix/power.ino
+++ b/flix/power.ino
@@ -3,8 +3,10 @@
 
 // Power management
 
+#ifndef CONFIG_IDF_TARGET_ESP32S31
 #include <soc/soc.h>
 #include <soc/rtc_cntl_reg.h>
+#endif
 #include "filter.h"
 #include "util.h"
 
@@ -14,7 +16,9 @@ int voltagePin = -1;
 float voltageScale = 2;
 
 void setupPower() {
+#ifndef CONFIG_IDF_TARGET_ESP32S31
 	REG_CLR_BIT(RTC_CNTL_BROWN_OUT_REG, RTC_CNTL_BROWN_OUT_ENA); // disable reset on low voltage
+#endif
 	if (digitalPinToAnalogChannel(voltagePin) == -1) voltagePin = -1; // test ADC pin
 }