add ADC support

esphome/components/adc/__init__.py

@@ -193,4 +193,15 @@ def validate_adc_pin(value):
             {CONF_ANALOG: True, CONF_INPUT: True}, internal=True
         )(value)
 
+    if CORE.is_nrf52:
+        conf = pins.gpio_pin_schema(
+            {CONF_ANALOG: True, CONF_INPUT: True}, internal=True
+        )(value)
+        number = conf[CONF_NUMBER]
+        if number not in (2, 3, 4, 5, 28, 29, 30, 31):
+            raise cv.Invalid(
+                "nRF52840: Only pins 2, 3, 4, 5, 28, 29, 30 and 31 support ADC"
+            )
+        return conf
+
     raise NotImplementedError

esphome/components/adc/adc_sensor.cpp

@@ -294,6 +294,23 @@ float ADCSensor::sample() {
 }
 #endif  // USE_LIBRETINY
 
+#ifdef USE_NRF52
+float ADCSensor::sample() {
+  // https://infocenter.nordicsemi.com/pdf/nRF52840_PS_v1.1.pdf
+  // 6.23.2 Reference voltage and gain settings
+  // Default settings are internal reference with 1/6 gain (GND..3.6V ADC range)
+  // With internal reference, single-ended input (grounded negative input) and a gain of 1/6, the input range will be:
+  // Input range = (0.6 V)/(1/6) = 3.6 V
+
+   uint32_t raw = analogRead(this->pin_->get_pin());  // NOLINT
+  if(output_raw_) {
+    return raw;
+  }
+  // default 10-bit resolution
+  return raw * 3.6f / 1024.0f;
+}
+#endif  // USE_NRF52
+
 #ifdef USE_ESP8266
 std::string ADCSensor::unique_id() { return get_mac_address() + "-adc"; }
 #endif

esphome/components/nrf52/gpio.py

@@ -7,6 +7,7 @@ from esphome.const import (
     CONF_MODE,
     CONF_INVERTED,
     CONF_NUMBER,
+    CONF_ANALOG,
 )
 
 nrf52_ns = cg.esphome_ns.namespace("nrf52")
@@ -44,6 +45,7 @@ NRF52_PIN_SCHEMA = cv.All(
     pins.gpio_base_schema(
         NRF52GPIOPin,
         validate_gpio_pin,
+        modes=pins.GPIO_STANDARD_MODES + (CONF_ANALOG,),
     ),
 )
 

tests/test12.yaml

@@ -34,7 +34,12 @@ sensor:
     pin: P0.10
     id: gpio_10
     update_interval: 3s
+  - platform: adc
+    pin: P0.29
+    id: adc4
+    update_interval: 1s
 
 dfu:
 
 beacon:
+