adc_cali: supported adc calibration on esp32c6

components/efuse/esp32c6/esp_efuse_rtc_calib.c

@@ -7,30 +7,76 @@
 #include <esp_bit_defs.h>
 #include "esp_efuse.h"
 #include "esp_efuse_table.h"
+#include "esp_efuse_rtc_calib.h"
 
 int esp_efuse_rtc_calib_get_ver(void)
 {
-    uint32_t result = 0;
-    esp_efuse_read_field_blob(ESP_EFUSE_BLK_VERSION_MAJOR, &result, ESP_EFUSE_BLK_VERSION_MAJOR[0]->bit_count); // IDF-5366
-    return result;
+    uint32_t blk_ver_minor = 0;
+    esp_efuse_read_field_blob(ESP_EFUSE_BLK_VERSION_MINOR, &blk_ver_minor, ESP_EFUSE_BLK_VERSION_MINOR[0]->bit_count);
+
+    uint32_t cali_version = (blk_ver_minor == 1) ? ESP_EFUSE_ADC_CALIB_VER : 0;
+    if (!cali_version) {
+        ESP_LOGW("eFuse", "calibration efuse version does not match, set default version to 0");
+    }
+
+    return blk_ver_minor;
 }
 
 uint32_t esp_efuse_rtc_calib_get_init_code(int version, uint32_t adc_unit, int atten)
 {
-    // Currently calibration is not supported on ESP32-C6, IDF-5236
-    (void) version;
+    assert(version == ESP_EFUSE_ADC_CALIB_VER);
     (void) adc_unit;
-    (void) atten;
-    return 0;
+    const esp_efuse_desc_t** init_code_efuse;
+    assert(atten < 4);
+    if (atten == 0) {
+        init_code_efuse = ESP_EFUSE_ADC1_INIT_CODE_ATTEN0;
+    } else if (atten == 1) {
+        init_code_efuse = ESP_EFUSE_ADC1_INIT_CODE_ATTEN1;
+    } else if (atten == 2) {
+        init_code_efuse = ESP_EFUSE_ADC1_INIT_CODE_ATTEN2;
+    } else {
+        init_code_efuse = ESP_EFUSE_ADC1_INIT_CODE_ATTEN3;
+    }
+
+    int init_code_size = esp_efuse_get_field_size(init_code_efuse);
+    assert(init_code_size == 10);
+
+    uint32_t init_code = 0;
+    ESP_ERROR_CHECK(esp_efuse_read_field_blob(init_code_efuse, &init_code, init_code_size));
+    return init_code + 1000;    // version 1 logic
 }
 
-esp_err_t esp_efuse_rtc_calib_get_cal_voltage(int version, int atten, uint32_t* out_digi, uint32_t* out_vol_mv)
+esp_err_t esp_efuse_rtc_calib_get_cal_voltage(int version, uint32_t adc_unit, int atten, uint32_t* out_digi, uint32_t* out_vol_mv)
 {
-    // Currently calibration is not supported on ESP32-C6, IDF-5236
-    (void) version;
-    (void) atten;
-    (void) out_digi;
-    (void) out_vol_mv;
+    (void) adc_unit;
+    const esp_efuse_desc_t** cal_vol_efuse;
+    uint32_t calib_vol_expected_mv;
+    if (version != ESP_EFUSE_ADC_CALIB_VER) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    if (atten >= 4 || atten < 0) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    if (atten == 0) {
+        cal_vol_efuse = ESP_EFUSE_ADC1_CAL_VOL_ATTEN0;
+        calib_vol_expected_mv = 400;
+    } else if (atten == 1) {
+        cal_vol_efuse = ESP_EFUSE_ADC1_CAL_VOL_ATTEN1;
+        calib_vol_expected_mv = 550;
+    } else if (atten == 2) {
+        cal_vol_efuse = ESP_EFUSE_ADC1_CAL_VOL_ATTEN2;
+        calib_vol_expected_mv = 750;
+    } else {
+        cal_vol_efuse = ESP_EFUSE_ADC1_CAL_VOL_ATTEN3;
+        calib_vol_expected_mv = 1370;
+    }
+    assert(cal_vol_efuse[0]->bit_count == 10);
+
+    uint32_t cal_vol = 0;
+    ESP_ERROR_CHECK(esp_efuse_read_field_blob(cal_vol_efuse, &cal_vol, cal_vol_efuse[0]->bit_count));
+
+    *out_digi = 2000 + ((cal_vol & BIT(9))? -(cal_vol & ~BIT9): cal_vol);
+    *out_vol_mv = calib_vol_expected_mv;
     return ESP_OK;
 }
 

components/efuse/esp32c6/include/esp_efuse_rtc_calib.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -35,6 +35,7 @@ uint32_t esp_efuse_rtc_calib_get_init_code(int version, uint32_t adc_unit, int a
  * @brief Get the calibration digits stored in the efuse, and the corresponding voltage.
  *
  * @param version Version of the stored efuse
+ * @param adc_unit      ADC unit (not used on ESP32C6, for compatibility)
  * @param atten         Attenuation to use
  * @param out_digi      Output buffer of the digits
  * @param out_vol_mv    Output of the voltage, in mV
@@ -42,7 +43,7 @@ uint32_t esp_efuse_rtc_calib_get_init_code(int version, uint32_t adc_unit, int a
  *      - ESP_ERR_INVALID_ARG: If efuse version or attenuation is invalid
  *      - ESP_OK: if success
  */
-esp_err_t esp_efuse_rtc_calib_get_cal_voltage(int version, int atten, uint32_t* out_digi, uint32_t* out_vol_mv);
+esp_err_t esp_efuse_rtc_calib_get_cal_voltage(int version, uint32_t adc_unit, int atten, uint32_t* out_digi, uint32_t* out_vol_mv);
 
 /**
  * @brief Get the temperature sensor calibration number delta_T stored in the efuse.

components/esp_adc/adc_cali_curve_fitting.c

@@ -160,7 +160,7 @@ static void get_first_step_reference_point(int version_num, adc_unit_t unit_id,
 
     uint32_t voltage = 0;
     uint32_t digi = 0;
-    ret = esp_efuse_rtc_calib_get_cal_voltage(version_num, unit_id, atten, &digi, &voltage);
+    ret = esp_efuse_rtc_calib_get_cal_voltage(version_num, unit_id, (int)atten, &digi, &voltage);
     assert(ret == ESP_OK);
     calib_info->ref_data.ver1.voltage = voltage;
     calib_info->ref_data.ver1.digi = digi;

components/esp_adc/esp32c6/curve_fitting_coefficients.c

@@ -0,0 +1,37 @@
+/*
+ * SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdint.h>
+
+/**
+ * @note Error Calculation
+ * Coefficients for calculating the reading voltage error.
+ * Four sets of coefficients for atten0 ~ atten3 respectively.
+ *
+ * For each item, first element is the Coefficient, second element is the Multiple. (Coefficient / Multiple) is the real coefficient.
+ *
+ * @note {0,0} stands for unused item
+ * @note In case of the overflow, these coeffcients are recorded as Absolute Value
+ * @note For atten0 ~ 2, error = (K0 * X^0) + (K1 * X^1) + (K2 * X^2); For atten3, error = (K0 * X^0) + (K1 * X^1)  + (K2 * X^2) + (K3 * X^3) + (K4 * X^4);
+ * @note Above formula is rewritten from the original documentation, please note that the coefficients are re-ordered.
+ * @note ADC1 and ADC2 use same coeffients
+ */
+const uint64_t adc1_error_coef_atten[4][5][2] = {
+                                                {{487166399931449,   1e16}, {6436483033201,   1e16}, {30410131806, 1e16}, {0, 0}, {0, 0}},   //atten0
+                                                {{8665498165817785,  1e16}, {15239070452946,  1e16}, {13818878844, 1e16}, {0, 0}, {0, 0}},   //atten1
+                                                {{12277821756674387, 1e16}, {22275554717885,  1e16}, {5924302667,  1e16}, {0, 0}, {0, 0}},   //atten2
+                                                {{3801417550380255,  1e16}, {6020352420772,   1e16}, {12442478488, 1e16}, {0, 0}, {0, 0}}    //atten3
+                                                };
+
+/**
+ * Term sign
+ */
+const int32_t adc1_error_sign[4][5] = {
+                                        {-1,  1, 1,  0,  0}, //atten0
+                                        {-1,  1, 1,  0,  0}, //atten1
+                                        {-1,  1, 1,  0,  0}, //atten2
+                                        {-1, -1, 1,  0,  0}  //atten3
+                                    };

components/esp_adc/esp32c6/include/adc_cali_schemes.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -12,4 +12,4 @@
  * @brief Supported calibration schemes
  */
 
-//Now no scheme supported
+#define ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED    1