[ESP32 ADC] Add option for raw uncalibrated output (#2663)

esphome/components/adc/adc_sensor.cpp

@@ -91,17 +91,21 @@ void ADCSensor::dump_config() {
 float ADCSensor::get_setup_priority() const { return setup_priority::DATA; }
 void ADCSensor::update() {
   float value_v = this->sample();
-  ESP_LOGD(TAG, "'%s': Got voltage=%.2fV", this->get_name().c_str(), value_v);
+  ESP_LOGD(TAG, "'%s': Got voltage=%.4fV", this->get_name().c_str(), value_v);
   this->publish_state(value_v);
 }
 
 #ifdef USE_ESP8266
 float ADCSensor::sample() {
 #ifdef USE_ADC_SENSOR_VCC
-  return ESP.getVcc() / 1024.0f;  // NOLINT(readability-static-accessed-through-instance)
+  int raw = ESP.getVcc();  // NOLINT(readability-static-accessed-through-instance)
 #else
-  return analogRead(this->pin_->get_pin()) / 1024.0f;  // NOLINT
+  int raw = analogRead(this->pin_->get_pin());  // NOLINT
 #endif
+  if (output_raw_) {
+    return raw;
+  }
+  return raw / 1024.0f;
 }
 #endif
 
@@ -112,6 +116,9 @@ float ADCSensor::sample() {
     if (raw == -1) {
       return NAN;
     }
+    if (output_raw_) {
+      return raw;
+    }
     uint32_t mv = esp_adc_cal_raw_to_voltage(raw, &cal_characteristics_[(int) attenuation_]);
     return mv / 1000.0f;
   }
@@ -135,10 +142,6 @@ float ADCSensor::sample() {
   if (raw0 == -1 || raw2 == -1 || raw6 == -1 || raw11 == -1) {
     return NAN;
   }
-  // prevent divide by zero
-  if (raw0 == 0 && raw2 == 0 && raw6 == 0 && raw11 == 0) {
-    return 0;
-  }
 
   uint32_t mv11 = esp_adc_cal_raw_to_voltage(raw11, &cal_characteristics_[(int) ADC_ATTEN_DB_11]);
   uint32_t mv6 = esp_adc_cal_raw_to_voltage(raw6, &cal_characteristics_[(int) ADC_ATTEN_DB_6]);

esphome/components/adc/adc_sensor.h

@@ -31,6 +31,7 @@ class ADCSensor : public sensor::Sensor, public PollingComponent, public voltage
   /// `HARDWARE_LATE` setup priority.
   float get_setup_priority() const override;
   void set_pin(InternalGPIOPin *pin) { this->pin_ = pin; }
+  void set_output_raw(bool output_raw) { output_raw_ = output_raw; }
   float sample() override;
 
 #ifdef USE_ESP8266
@@ -39,8 +40,7 @@ class ADCSensor : public sensor::Sensor, public PollingComponent, public voltage
 
  protected:
   InternalGPIOPin *pin_;
-  uint16_t read_raw_();
-  uint32_t raw_to_microvolts_(uint16_t raw);
+  bool output_raw_{false};
 
 #ifdef USE_ESP32
   adc_atten_t attenuation_{ADC_ATTEN_DB_0};

esphome/components/adc/sensor.py

@@ -4,6 +4,7 @@ from esphome import pins
 from esphome.components import sensor, voltage_sampler
 from esphome.const import (
     CONF_ATTENUATION,
+    CONF_RAW,
     CONF_ID,
     CONF_INPUT,
     CONF_NUMBER,
@@ -119,12 +120,18 @@ def validate_adc_pin(value):
     raise NotImplementedError
 
 
+def validate_config(config):
+    if config[CONF_RAW] and config.get(CONF_ATTENUATION, None) == "auto":
+        raise cv.Invalid("Automatic attenuation cannot be used when raw output is set.")
+    return config
+
+
 adc_ns = cg.esphome_ns.namespace("adc")
 ADCSensor = adc_ns.class_(
     "ADCSensor", sensor.Sensor, cg.PollingComponent, voltage_sampler.VoltageSampler
 )
 
-CONFIG_SCHEMA = (
+CONFIG_SCHEMA = cv.All(
     sensor.sensor_schema(
         unit_of_measurement=UNIT_VOLT,
         accuracy_decimals=2,
@@ -135,12 +142,14 @@ CONFIG_SCHEMA = (
         {
             cv.GenerateID(): cv.declare_id(ADCSensor),
             cv.Required(CONF_PIN): validate_adc_pin,
+            cv.Optional(CONF_RAW, default=False): cv.boolean,
             cv.SplitDefault(CONF_ATTENUATION, esp32="0db"): cv.All(
                 cv.only_on_esp32, cv.enum(ATTENUATION_MODES, lower=True)
             ),
         }
     )
-    .extend(cv.polling_component_schema("60s"))
+    .extend(cv.polling_component_schema("60s")),
+    validate_config,
 )
 
 
@@ -155,6 +164,9 @@ async def to_code(config):
         pin = await cg.gpio_pin_expression(config[CONF_PIN])
         cg.add(var.set_pin(pin))
 
+    if CONF_RAW in config:
+        cg.add(var.set_output_raw(config[CONF_RAW]))
+
     if CONF_ATTENUATION in config:
         if config[CONF_ATTENUATION] == "auto":
             cg.add(var.set_autorange(cg.global_ns.true))