# Copyright (c) 2022 Wolter HV <wolterhv@gmx.de>
#
# SPDX-License-Identifier: Apache-2.0

description: |
  Espressif ESP32 ADC
  Possible available resolutions depends on the used chip.
    - ESP32     < 9,10,11,12 >
    - ESP32-S2  < 12 >
    - ESP32-C3  < 12 >
  For chips with configurable resolution feature (ESP32),
  maximum resolution will be used if not set explicitly.

  Zephyr API is using gain unit to characterize ADC input.
  To achieve compatibility we choose to select those gain,
  which coresponds to the ESP32 ADC attenuation feature.

    ESP32,attenuation ~ zephyr,gain
    -----------------   -----------
    0 dB                ADC_GAIN_1
    2.5 dB              ADC_GAIN_4_5
    6 dB                ADC_GAIN_1_2
    11 dB               ADC_GAIN_1_4

  In case unsupported gain is selected the adc_channel_setup()
  would return ENOTSUP error.

compatible: "espressif,esp32-adc"

include: [adc-controller.yaml]

properties:

  unit:
    type: int
    required: true
    description: ADC unit number.
      Possible values are 1,2,.. depending on chip.

  channel-count:
    type: int
    required: true
    description: The maximum channels supported on each unit.

  "#io-channel-cells":
    const: 1

io-channel-cells:
  - input