dts/bindings/rtc/atmel,sam0-rtc.yaml

# Copyright (c) 2018 omSquare s.r.o.
# Copyright (c) 2024-2025 Gerson Fernando Budke <nandojve@gmail.com>
# SPDX-License-Identifier: Apache-2.0

description: Atmel SAM0 RTC

compatible: "atmel,sam0-rtc"

include:
  - name: rtc-device.yaml
  - name: pinctrl-device.yaml
  - name: atmel,assigned-clocks.yaml

properties:
  reg:
    required: true

  clocks:
    required: true

  clock-names:
    required: true

  atmel,assigned-clocks:
    required: true

  atmel,assigned-clock-names:
    required: true

  systimer:
    type: boolean
    description: |
      Selects RTC peripheral to be used as a system timer and replace
      the ARM systick. When this option is selected the normal RTC
      functionality is in exclusive mode and the normal RTC functions
      will not be available.

      The systimer exclusive functionality can be enabled using the
      following devicetree entry:

        &rtc {
          status = "okay";
          systimer;
        };

  cal-constant:
    type: int
    required: true
    description: |
      Define the constant used to calculate the calibration. More
      information can be found in the datasheet of each SoC series
      at RTC Frequency Correction topic.

      Example:
        Correction in ppm = (FREQCORR.VALUE * 1e6 ppm) / (8192 * 128)

        &rtc {
          cal-constant = <8192 * 128>;
        };

  counter-mode:
    type: string
    enum:
      - "count-32"
      - "count-16"
      - "clock"
    description: |
      Configure the RTC counter operating mode. In mode 0, the counter
      register is configured as a 32-bit counter. In mode 1, simmilar
      to mode 0, the counter register is only 16-bit counter. In mode
      2 the counter register is configured as a clock/calendar.

        &rtc {
          status = "okay";
          counter-mode = "clock";
          prescaler = <1024>;
        };

  prescaler:
    type: int
    enum:
      - 1
      - 2
      - 4
      - 8
      - 16
      - 32
      - 64
      - 128
      - 256
      - 512
      - 1024
    description: |
      Enable CLKOUT at given frequency. When disabled, CLKOUT pin is LOW.
      The default is 0 and corresponds to the disable the CLKOUT signal.

        &rtc {
          status = "okay";
          counter-mode = "clock";
          prescaler = <1024>;
        };

  event-control-msk:
    type: int
    default: 0
    description: |
      Enable peripheral event sources by bitmask. By default all the channels
      are always disabled.

      Event Table:

        bit   Event Source
         0    Periodic Interval 0 Event Output
         1    Periodic Interval 1 Event Output
         2    Periodic Interval 2 Event Output
         3    Periodic Interval 3 Event Output
         4    Periodic Interval 4 Event Output
         5    Periodic Interval 5 Event Output
         6    Periodic Interval 6 Event Output
         7    Periodic Interval 7 Event Output
         8    Compare/Alarm 0 Event Output
         9    Compare/Alarm 1 Event Output
        14    Tamper Event Output
        15    Overflow Event Output
        16    Tamper Event Input

      Example how to enable Compare/Alarm 0 Event Output:
        &rtc {
          event-control-msk = <100>;
        };