esp-idf/components/esp_adc_cal/esp_adc_cal_common.c

/*
 * SPDX-FileCopyrightText: 2020-2022 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <stdint.h>
#include <string.h>
#include "esp_types.h"
#include "esp_err.h"
#include "esp_log.h"
#include "esp_check.h"
#include "driver/adc.h"
#include "hal/adc_types.h"
#include "esp_adc_cal.h"

const __attribute__((unused)) static char *TAG = "ADC_CALI";

esp_err_t esp_adc_cal_get_voltage(adc_channel_t channel,
                                  const esp_adc_cal_characteristics_t *chars,
                                  uint32_t *voltage)
{
    // Check parameters
    ESP_RETURN_ON_FALSE(chars != NULL, ESP_ERR_INVALID_ARG, TAG, "No characteristic input");
    ESP_RETURN_ON_FALSE(voltage != NULL, ESP_ERR_INVALID_ARG, TAG, "No output buffer");

    esp_err_t ret = ESP_OK;
    int adc_reading;
    if (chars->adc_num == ADC_UNIT_1) {
        ESP_RETURN_ON_FALSE(channel < SOC_ADC_CHANNEL_NUM(0), ESP_ERR_INVALID_ARG, TAG, "Invalid channel");
        adc_reading = adc1_get_raw(channel);
    } else {
        ESP_RETURN_ON_FALSE(channel < SOC_ADC_CHANNEL_NUM(1), ESP_ERR_INVALID_ARG, TAG, "Invalid channel");
        ret = adc2_get_raw(channel, chars->bit_width, &adc_reading);
    }

    if (ret == ESP_OK) {
        *voltage = esp_adc_cal_raw_to_voltage((uint32_t)adc_reading, chars);
    }
    return ret;
}