/* * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD * * SPDX-License-Identifier: Apache-2.0 */ #include #include #include #include "esp_types.h" #include "esp_err.h" #include "esp_log.h" #include "esp_check.h" #include "esp_heap_caps.h" #include "esp_efuse_rtc_calib.h" #include "soc/soc_caps.h" #include "esp_adc/adc_cali_scheme.h" #include "adc_cali_interface.h" /** * This file contains Line Fitting Calibration Scheme for ESP32C2. * * If ESP EFuse Line Fitting Calibration Scheme on future chips are similar to the scheme in this file, we can: * * 1. Rename this file to `adc_cali_line_fitting_v2.c`, as the Line Fitting Scheme on ESP32 and ESP32S2 are different to this. * 2. Move this file to common directory * 3. Still support `ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED` * 4. Add a new internal maccro `ADC_CALI_SCHEME_LINE_FITTING_V2_SUPPORTED` * 5. Only build this file, when `ADC_CALI_SCHEME_LINE_FITTING_V2_SUPPORTED == true` */ // coeff_a is actually a float number // it is scaled to put them into uint32_t so that the headers do not have to be changed static const int coeff_a_scaling = 65536; const static char *TAG = "adc_cali"; typedef struct { adc_unit_t unit_id; adc_atten_t atten; uint32_t coeff_a; ///< Gradient of ADC-Voltage characteristics uint32_t coeff_b; ///< Offset of ADC-Voltage characteristics } cali_chars_line_fitting_t; /* ------------------------ Interface Functions --------------------------- */ static esp_err_t cali_raw_to_voltage(void *arg, int raw, int *voltage); static esp_err_t check_valid(const adc_cali_line_fitting_config_t *config); /* ------------------------- Public API ------------------------------------- */ esp_err_t adc_cali_create_scheme_line_fitting(const adc_cali_line_fitting_config_t *config, adc_cali_handle_t *ret_handle) { esp_err_t ret = ESP_OK; ESP_RETURN_ON_FALSE(config && ret_handle, ESP_ERR_INVALID_ARG, TAG, "invalid arg: null pointer"); ret = check_valid(config); if (ret != ESP_OK) { return ret; } //current version only accepts encoding version: `ESP_EFUSE_ADC_CALIB_VER`. uint8_t adc_cali_version = esp_efuse_rtc_calib_get_ver(); ESP_RETURN_ON_FALSE(adc_cali_version == ESP_EFUSE_ADC_CALIB_VER, ESP_ERR_NOT_SUPPORTED, TAG, "Calibration required eFuse bits not burnt"); adc_cali_scheme_t *scheme = (adc_cali_scheme_t *)heap_caps_calloc(1, sizeof(adc_cali_scheme_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT); ESP_RETURN_ON_FALSE(scheme, ESP_ERR_NO_MEM, TAG, "no mem for adc calibration scheme"); cali_chars_line_fitting_t *chars = (cali_chars_line_fitting_t *)heap_caps_calloc(1, sizeof(cali_chars_line_fitting_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT); ESP_GOTO_ON_FALSE(chars, ESP_ERR_NO_MEM, err, TAG, "no memory for the calibration characteristics"); scheme->raw_to_voltage = cali_raw_to_voltage; scheme->ctx = chars; chars->unit_id = config->unit_id; chars->atten = config->atten; uint32_t voltage_mv = 0; uint32_t digi_val = 0; esp_efuse_rtc_calib_get_cal_voltage(adc_cali_version, chars->unit_id, chars->atten, &digi_val, &voltage_mv); assert(ret == ESP_OK); chars->coeff_a = coeff_a_scaling * voltage_mv / digi_val; chars->coeff_b = 0; ESP_LOGV(TAG, "Calib V1, Cal Voltage = %"PRId32", Digi out = %"PRId32", Coef_a = %"PRId32"\n", voltage_mv, digi_val, chars->coeff_a); *ret_handle = scheme; return ESP_OK; err: if (scheme) { free(scheme); } return ret; } esp_err_t adc_cali_delete_scheme_line_fitting(adc_cali_handle_t handle) { ESP_RETURN_ON_FALSE(handle, ESP_ERR_INVALID_ARG, TAG, "invalid argument: null pointer"); free(handle->ctx); handle->ctx = NULL; free(handle); handle = NULL; return ESP_OK; } /* ------------------------ Interface Functions --------------------------- */ static esp_err_t cali_raw_to_voltage(void *arg, int raw, int *voltage) { //pointers are checked in the upper layer cali_chars_line_fitting_t *ctx = arg; *voltage = raw * ctx->coeff_a / coeff_a_scaling + ctx->coeff_b; return ESP_OK; } static esp_err_t check_valid(const adc_cali_line_fitting_config_t *config) { ESP_RETURN_ON_FALSE(config->unit_id < SOC_ADC_PERIPH_NUM, ESP_ERR_INVALID_ARG, TAG, "invalid ADC unit"); ESP_RETURN_ON_FALSE((config->atten == ADC_ATTEN_DB_0 || config->atten == ADC_ATTEN_DB_11), ESP_ERR_NOT_SUPPORTED, TAG, "only ADC_ATTEN_DB_0 and ADC_ATTEN_DB_11 are supported"); if (config->atten == ADC_ATTEN_DB_0) { ESP_LOGW(TAG, "Experimental: ADC Atten 0 calibration can now only used for inputs lower than 950mV. Calibration Scheme may get updated, DON'T USE FOR MASS PRODUCTION!"); } bool available_oneshot_bitwidth = (config->bitwidth >= SOC_ADC_RTC_MIN_BITWIDTH && config->bitwidth <= SOC_ADC_RTC_MAX_BITWIDTH); bool available_dma_bitwidth = (config->bitwidth >= SOC_ADC_DIGI_MIN_BITWIDTH && config->bitwidth <= SOC_ADC_DIGI_MAX_BITWIDTH); bool default_bitwidth_mark = (config->bitwidth == ADC_BITWIDTH_DEFAULT); bool available_bitwidth = (available_oneshot_bitwidth || available_dma_bitwidth || default_bitwidth_mark); ESP_RETURN_ON_FALSE(available_bitwidth, ESP_ERR_INVALID_ARG, TAG, "invalid bitwidth"); return ESP_OK; }