Migrate to the v5 adc api

src/drivers/CMakeLists.txt

@@ -2,5 +2,5 @@ idf_component_register(
   SRCS "dac.cpp" "gpio_expander.cpp" "battery.cpp" "storage.cpp" "i2c.cpp"
   "spi.cpp" "display.cpp" "display_init.cpp"
   INCLUDE_DIRS "include"
-  REQUIRES "esp_adc_cal" "fatfs" "result" "lvgl" "span")
+  REQUIRES "esp_adc" "fatfs" "result" "lvgl" "span")
 target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})

src/drivers/battery.cpp

@@ -1,31 +1,54 @@
 #include "battery.hpp"
+#include <cstdint>
 
-#include "driver/adc.h"
-#include "esp_adc_cal.h"
+#include "esp_adc/adc_oneshot.h"
 #include "hal/adc_types.h"
 
 namespace drivers {
 
-static esp_adc_cal_characteristics_t calibration;
-
-esp_err_t init_adc(void) {
-  // Calibration should already be fused into the chip from the factory, so
-  // we should only need to read it back out again.
-  esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_11, ADC_WIDTH_BIT_12, 0,
-                           &calibration);
-
-  // Max battery voltage should be a little over 2V due to our divider, so
-  // we need the max attenuation to properly handle the full range.
-  adc1_config_width(ADC_WIDTH_BIT_12);
-  adc1_config_channel_atten(ADC1_CHANNEL_6, ADC_ATTEN_DB_11);
+static const uint8_t kAdcBitWidth = ADC_BITWIDTH_12;
+static const uint8_t kAdcUnit = ADC_UNIT_1;
+// Max battery voltage should be a little over 2V due to our divider, so we need
+// the max attenuation to properly handle the full range.
+static const uint8_t kAdcAttenuation = ADC_ATTEN_DB_11;
+// Corresponds to GPIO 34.
+static const uint8_t kAdcChannel = ADC_CHANNEL_6;
+
+Battery::Battery() {
+  adc_oneshot_unit_init_cfg_t unit_config = {
+    .unit_id = kAdcUnit,
+  };
+  ESP_ERROR_CHECK(adc_oneshot_new_unit(&unit_config, &adc_handle_));
+
+  adc_oneshot_chan_cfg_t channel_config = {
+    .bitwidth = kAdcBitWidth,
+    .atten = kAdcAttenuation,
+  };
+  ESP_ERROR_CHECK(adc_oneshot_config_channel(adc_handle_, kAdcChannel, &channel_config));
+  
+  // calibrate
+  // TODO: compile-time assert our scheme is available
+  adc_cali_line_fitting_config_t calibration_config = {
+    .unit_id = kAdcUnit,
+    .atten = kAdcAttenuation,
+    .bitwidth = kAdcBitWidth,
+  };
+  ESP_ERROR_CHECK(adc_cali_create_scheme_line_fitting(&calibration_config, &adc_calibration_handle_));
+}
 
-  return ESP_OK;
+Battery::~Battery() {
+  adc_cali_delete_scheme_line_fitting(adc_calibration_handle_);
 }
 
-uint32_t read_battery_voltage(void) {
+auto Battery::Millivolts() -> uint32_t {
   // GPIO 34
-  int raw = adc1_get_raw(ADC1_CHANNEL_6);
-  return esp_adc_cal_raw_to_voltage(raw, &calibration);
+  int raw;
+  ESP_ERROR_CHECK(adc_oneshot_read(adc_handle, kAdcChannel &raw));
+
+  int voltage;
+  ESP_ERROR_CHECK(adc_cali_raw_to_voltage(adc_calibration_handle, raw, &voltage));
+
+  return voltage;
 }
 
 }  // namespace drivers

src/drivers/include/battery.hpp

@@ -1,16 +1,25 @@
 #pragma once
 
-#include <stdint.h>
+#include <cstdint>
 
+#include "esp_adc/adc_oneshot.h"
 #include "esp_err.h"
+#include "result.hpp"
 
 namespace drivers {
 
-esp_err_t init_adc(void);
+class Battery {
+  public:
+    Battery();
+    ~Battery();
 
-/**
+    /**
      * Returns the current battery level in millivolts.
      */
-uint32_t read_battery_voltage(void);
+    auto Millivolts() -> uint32_t;
+  private:
+    adc_oneshot_handle_t adc_handle_;
+    adc_cali_handle_t adc_calibration_handle_;
+};
 
 }  // namespace drivers

src/main/main.cpp

@@ -92,7 +92,6 @@ extern "C" void app_main(void) {
   ESP_ERROR_CHECK(gpio_install_isr_service(ESP_INTR_FLAG_LOWMED));
   ESP_ERROR_CHECK(drivers::init_i2c());
   ESP_ERROR_CHECK(drivers::init_spi());
-  ESP_ERROR_CHECK(drivers::init_adc());
 
   ESP_LOGI(TAG, "Init GPIOs");
   drivers::GpioExpander* expander = new drivers::GpioExpander();
@@ -105,6 +104,10 @@ extern "C" void app_main(void) {
                  drivers::GpioExpander::SD_MUX_ESP);
   });
 
+  ESP_LOGI(TAG, "Init battery measurement");
+  drivers::Battery* battery = new drivers::Battery();
+  ESP_LOGI(TAG, "it's reading %dmV!", battery->Millivolts());
+
   ESP_LOGI(TAG, "Init SD card");
   auto storage_res = drivers::SdStorage::create(expander);
   if (storage_res.has_error()) {