esp32s2: add brownout detector support

1. add brownout detector HAL for esp32 and esp32s2
2. enable brownout reset for esp32 rev. 1 and above
3. add approximate brownout detector levels for esp32s2

components/esp32/brownout.c

@@ -20,6 +20,7 @@
 #include "soc/soc.h"
 #include "soc/cpu.h"
 #include "soc/rtc_periph.h"
+#include "hal/brownout_hal.h"
 #include "esp32/rom/ets_sys.h"
 #include "esp_private/system_internal.h"
 #include "driver/rtc_cntl.h"
@@ -49,14 +50,17 @@ static void rtc_brownout_isr_handler(void *arg)
 
 void esp_brownout_init(void)
 {
-    REG_WRITE(RTC_CNTL_BROWN_OUT_REG,
-            RTC_CNTL_BROWN_OUT_ENA /* Enable BOD */
-            | RTC_CNTL_BROWN_OUT_PD_RF_ENA /* Automatically power down RF */
-            /* Reset timeout must be set to >1 even if BOR feature is not used */
-            | (2 << RTC_CNTL_BROWN_OUT_RST_WAIT_S)
-            | (BROWNOUT_DET_LVL << RTC_CNTL_DBROWN_OUT_THRES_S));
+    brownout_hal_config_t cfg = {
+        .threshold = BROWNOUT_DET_LVL,
+        .enabled = true,
+        .reset_enabled = false,
+        .flash_power_down = true,
+        .rf_power_down = true,
+    };
+
+    brownout_hal_config(&cfg);
 
     ESP_ERROR_CHECK( rtc_isr_register(rtc_brownout_isr_handler, NULL, RTC_CNTL_BROWN_OUT_INT_ENA_M) );
 
-    REG_SET_BIT(RTC_CNTL_INT_ENA_REG, RTC_CNTL_BROWN_OUT_INT_ENA_M);
+    brownout_hal_intr_enable(true);
 }

components/esp32s2/Kconfig

@@ -364,42 +364,39 @@ menu "ESP32S2-specific"
         bool "Hardware brownout detect & reset"
         default y
         help
-            The ESP32S2 has a built-in brownout detector which can detect if the voltage is lower than
+            The ESP32-S2 has a built-in brownout detector which can detect if the voltage is lower than
             a specific value. If this happens, it will reset the chip in order to prevent unintended
             behaviour.
 
     choice ESP32S2_BROWNOUT_DET_LVL_SEL
         prompt "Brownout voltage level"
         depends on ESP32S2_BROWNOUT_DET
-        default ESP32S2_BROWNOUT_DET_LVL_SEL_0
+        default ESP32S2_BROWNOUT_DET_LVL_SEL_7
         help
             The brownout detector will reset the chip when the supply voltage is approximately
             below this level. Note that there may be some variation of brownout voltage level
-            between each ESP32 chip.
+            between each ESP3-S2 chip.
 
             #The voltage levels here are estimates, more work needs to be done to figure out the exact voltages
             #of the brownout threshold levels.
-        config ESP32S2_BROWNOUT_DET_LVL_SEL_0
-            bool "2.43V +/- 0.05"
-        config ESP32S2_BROWNOUT_DET_LVL_SEL_1
-            bool "2.48V +/- 0.05"
-        config ESP32S2_BROWNOUT_DET_LVL_SEL_2
-            bool "2.58V +/- 0.05"
-        config ESP32S2_BROWNOUT_DET_LVL_SEL_3
-            bool "2.62V +/- 0.05"
-        config ESP32S2_BROWNOUT_DET_LVL_SEL_4
-            bool "2.67V +/- 0.05"
-        config ESP32S2_BROWNOUT_DET_LVL_SEL_5
-            bool "2.70V +/- 0.05"
-        config ESP32S2_BROWNOUT_DET_LVL_SEL_6
-            bool "2.77V +/- 0.05"
         config ESP32S2_BROWNOUT_DET_LVL_SEL_7
-            bool "2.80V +/- 0.05"
+            bool "2.44V"
+        config ESP32S2_BROWNOUT_DET_LVL_SEL_6
+            bool "2.56V"
+        config ESP32S2_BROWNOUT_DET_LVL_SEL_5
+            bool "2.67V"
+        config ESP32S2_BROWNOUT_DET_LVL_SEL_4
+            bool "2.84V"
+        config ESP32S2_BROWNOUT_DET_LVL_SEL_3
+            bool "2.98V"
+        config ESP32S2_BROWNOUT_DET_LVL_SEL_2
+            bool "3.19V"
+        config ESP32S2_BROWNOUT_DET_LVL_SEL_1
+            bool "3.30V"
     endchoice
 
     config ESP32S2_BROWNOUT_DET_LVL
         int
-        default 0 if ESP32S2_BROWNOUT_DET_LVL_SEL_0
         default 1 if ESP32S2_BROWNOUT_DET_LVL_SEL_1
         default 2 if ESP32S2_BROWNOUT_DET_LVL_SEL_2
         default 3 if ESP32S2_BROWNOUT_DET_LVL_SEL_3

components/esp32s2/brownout.c

@@ -17,10 +17,11 @@
 #include <stdlib.h>
 #include <stdbool.h>
 #include "sdkconfig.h"
+#include "esp_log.h"
 #include "soc/soc.h"
 #include "soc/cpu.h"
-#include "soc/rtc_cntl_reg.h"
-#include "esp32s2/rom/ets_sys.h"
+#include "soc/rtc_periph.h"
+#include "hal/brownout_hal.h"
 #include "esp_private/system_internal.h"
 #include "driver/rtc_cntl.h"
 #include "freertos/FreeRTOS.h"
@@ -42,15 +43,24 @@ static void rtc_brownout_isr_handler(void *arg)
      * at the same time as the following ets_printf.
      */
     esp_cpu_stall(!xPortGetCoreID());
+    esp_reset_reason_set_hint(ESP_RST_BROWNOUT);
     ets_printf("\r\nBrownout detector was triggered\r\n\r\n");
     esp_restart_noos();
 }
 
 void esp_brownout_init(void)
 {
-// TODO: implement brownout threshold configuration for esp32s2 - IDF-751
+    brownout_hal_config_t cfg = {
+        .threshold = BROWNOUT_DET_LVL,
+        .enabled = true,
+        .reset_enabled = false,
+        .flash_power_down = true,
+        .rf_power_down = true,
+    };
+
+    brownout_hal_config(&cfg);
 
     ESP_ERROR_CHECK( rtc_isr_register(rtc_brownout_isr_handler, NULL, RTC_CNTL_BROWN_OUT_INT_ENA_M) );
 
-    REG_SET_BIT(RTC_CNTL_INT_ENA_REG, RTC_CNTL_BROWN_OUT_INT_ENA_M);
+    brownout_hal_intr_enable(true);
 }

components/soc/esp32/brownout_hal.c

@@ -0,0 +1,41 @@
+
+// Copyright 2020 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.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "hal/brownout_hal.h"
+#include "soc/rtc_cntl_struct.h"
+
+void brownout_hal_config(const brownout_hal_config_t *cfg)
+{
+    typeof(RTCCNTL.brown_out) brown_out_reg = {
+        .close_flash_ena = cfg->flash_power_down,
+        .pd_rf_ena = cfg->rf_power_down,
+        .rst_wait = 0x3ff,
+        .rst_ena = cfg->reset_enabled,
+        .thres = cfg->threshold,
+        .ena = cfg->enabled,
+    };
+
+    RTCCNTL.brown_out = brown_out_reg;
+}
+
+void brownout_hal_intr_enable(bool enable)
+{
+    RTCCNTL.int_ena.rtc_brown_out = enable;
+}
+
+void brownout_hal_intr_clear(void)
+{
+    RTCCNTL.int_clr.rtc_brown_out = 1;
+}

components/soc/esp32/include/soc/brownout_caps.h

@@ -0,0 +1,27 @@
+// Copyright 2020 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.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if (CONFIG_ESP32_REV_MIN >= 1)
+#define SOC_BROWNOUT_RESET_SUPPORTED 1
+#endif
+
+#ifdef __cplusplus
+}
+#endif

components/soc/esp32/sources.cmake

@@ -1,4 +1,5 @@
 set(SOC_SRCS "adc_periph.c"
+    "brownout_hal.c"
     "dac_periph.c"
     "cpu_util.c"
     "gpio_periph.c"

components/soc/esp32s2/brownout_hal.c

@@ -0,0 +1,46 @@
+
+// Copyright 2020 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.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "hal/brownout_hal.h"
+#include "soc/rtc_cntl_struct.h"
+#include "soc/rtc_cntl_reg.h"
+#include "i2c_rtc_clk.h"
+#include "i2c_brownout.h"
+
+
+void brownout_hal_config(const brownout_hal_config_t *cfg)
+{
+    I2C_WRITEREG_MASK_RTC(I2C_BOD, I2C_BOD_THRESHOLD, cfg->threshold);
+    typeof(RTCCNTL.brown_out) brown_out_reg = {
+        .out2_ena = 1,
+        .int_wait = 0x002,
+        .close_flash_ena = cfg->flash_power_down,
+        .pd_rf_ena = cfg->rf_power_down,
+        .rst_wait = 0x3ff,
+        .rst_ena = cfg->reset_enabled,
+        .ena = cfg->enabled,
+    };
+    RTCCNTL.brown_out = brown_out_reg;
+}
+
+void brownout_hal_intr_enable(bool enable)
+{
+    RTCCNTL.int_ena.rtc_brown_out = enable;
+}
+
+void brownout_hal_intr_clear(void)
+{
+    RTCCNTL.int_clr.rtc_brown_out = 1;
+}

components/soc/esp32s2/i2c_brownout.h

@@ -0,0 +1,30 @@
+// Copyright 2020 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.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+/**
+ * @file i2c_brownout.h
+ * @brief Register definitions for brownout detector
+ *
+ * This file lists register fields of the brownout detector, located on an internal configuration
+ * bus. These definitions are used via macros defined in i2c_rtc_clk.h.
+ */
+
+#define I2C_BOD            0x61
+#define I2C_BOD_HOSTID     1
+
+#define I2C_BOD_THRESHOLD           0x5
+#define I2C_BOD_THRESHOLD_MSB       2
+#define I2C_BOD_THRESHOLD_LSB       0

components/soc/esp32s2/include/soc/brownout_caps.h

@@ -0,0 +1,25 @@
+// Copyright 2020 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.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define SOC_BROWNOUT_RESET_SUPPORTED 1
+
+#ifdef __cplusplus
+}
+#endif

components/soc/esp32s2/sources.cmake

@@ -1,4 +1,5 @@
 set(SOC_SRCS    "adc_periph.c"
+                "brownout_hal.c"
                 "dac_periph.c"
                 "cpu_util.c"
                 "gpio_periph.c"

components/soc/include/hal/brownout_hal.h

@@ -0,0 +1,47 @@
+// Copyright 2020 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.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/*******************************************************************************
+ * NOTICE
+ * The hal is not public api, don't use in application code.
+ * See readme.md in soc/include/hal/readme.md
+ ******************************************************************************/
+
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef struct {
+    uint8_t threshold;
+    bool enabled;
+    bool reset_enabled;
+    bool flash_power_down;
+    bool rf_power_down;
+} brownout_hal_config_t;
+
+void brownout_hal_config(const brownout_hal_config_t *cfg);
+
+void brownout_hal_intr_enable(bool enable);
+
+void brownout_hal_intr_clear(void);
+
+#ifdef __cplusplus
+}
+#endif