From cf87e114cb8db234e819f6e5f73babf672ecb6d2 Mon Sep 17 00:00:00 2001
From: Marius Vikhammer <marius.vikhammer@espressif.com>
Date: Tue, 9 Feb 2021 19:30:43 +0800
Subject: [PATCH] deep_sleep: on S2 disable the brown out detector before deep
 sleeping

On S2 the brown out detector would occasionally trigger erroneously during deep sleep.

Disable it before sleeping to circumvent this issue.

Closes https://github.com/espressif/esp-idf/issues/6179
---
 components/esp32/include/esp32/brownout.h     | 12 +++++++++++-
 components/esp32s2/include/esp32s2/brownout.h |  4 +++-
 components/esp32s2/sleep_modes.c              |  5 +++++
 components/esp_common/src/brownout.c          | 15 +++++++++++++++
 4 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/components/esp32/include/esp32/brownout.h b/components/esp32/include/esp32/brownout.h
index dafba8dd79..7fbe98c11a 100644
--- a/components/esp32/include/esp32/brownout.h
+++ b/components/esp32/include/esp32/brownout.h
@@ -16,6 +16,16 @@
 #ifndef __ESP_BROWNOUT_H
 #define __ESP_BROWNOUT_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void esp_brownout_init(void);
 
-#endif
\ No newline at end of file
+void esp_brownout_disable(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/components/esp32s2/include/esp32s2/brownout.h b/components/esp32s2/include/esp32s2/brownout.h
index d0c120dd0f..e83cf1450a 100644
--- a/components/esp32s2/include/esp32s2/brownout.h
+++ b/components/esp32s2/include/esp32s2/brownout.h
@@ -1,4 +1,4 @@
-// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
+// Copyright 2015-2021 Espressif Systems (Shanghai) PTE LTD
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -22,6 +22,8 @@ extern "C" {
 
 void esp_brownout_init(void);
 
+void esp_brownout_disable(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/esp32s2/sleep_modes.c b/components/esp32s2/sleep_modes.c
index b74b95342b..dced1af243 100644
--- a/components/esp32s2/sleep_modes.c
+++ b/components/esp32s2/sleep_modes.c
@@ -26,6 +26,7 @@
 #include "esp32s2/rom/rtc.h"
 #include "esp32s2/rom/uart.h"
 #include "esp32s2/rom/ets_sys.h"
+#include "esp32s2/brownout.h"
 #include "soc/cpu.h"
 #include "soc/rtc.h"
 #include "soc/spi_periph.h"
@@ -229,6 +230,10 @@ static uint32_t IRAM_ATTR esp_sleep_start(uint32_t pd_flags)
 
 void IRAM_ATTR esp_deep_sleep_start(void)
 {
+    /* Due to hardware limitations, on S2 the brownout detector sometimes trigger during deep sleep
+       to circumvent this we disable the brownout detector before sleeping  */
+    esp_brownout_disable();
+
     // record current RTC time
     s_config.rtc_ticks_at_sleep_start = rtc_time_get();
     esp_sync_counters_rtc_and_frc();
diff --git a/components/esp_common/src/brownout.c b/components/esp_common/src/brownout.c
index 57f62cefac..e216cfa0fa 100644
--- a/components/esp_common/src/brownout.c
+++ b/components/esp_common/src/brownout.c
@@ -73,3 +73,18 @@ void esp_brownout_init(void)
 
     brownout_hal_intr_enable(true);
 }
+
+void esp_brownout_disable(void)
+{
+    brownout_hal_config_t cfg = {
+        .enabled = false,
+    };
+
+    brownout_hal_config(&cfg);
+
+#ifndef SOC_BROWNOUT_RESET_SUPPORTED
+    brownout_hal_intr_enable(false);
+
+    rtc_isr_deregister(rtc_brownout_isr_handler, NULL);
+#endif // not SOC_BROWNOUT_RESET_SUPPORTED
+}