dts/bindings/watchdog/gd,gd32-fwdgt.yaml

# Copyright (c) 2021, TOKITA Hiroshi
# SPDX-License-Identifier: Apache-2.0

description: GD32 free watchdog timer

compatible: "gd,gd32-fwdgt"

include: base.yaml

properties:
    reg:
      required: true

    initial-timeout-ms:
      type: int
      default: 250
      description: |
        Set timeout value in milliseconds.
        The following equation gives the maximum timeout value

          timeout = (reload + 1) / (peripheral_freqency / prescaler).

        where the maximum prescaler = 256 and the maximum reload = 4096.
        The peripheral_frequency uses GD32_LOW_SPEED_IRC_FREQUENCY
        that defined in modules/hal_gigadevice/Kconfig.
        Validate the value is within a capable range at the compile time.

        The default value defined is close to the register reset value
        from values that don't cause calculation errors in both cases of
        the low-speed internal RC oscillator frequency is 32kHz or 40kHz.

        0.25 [timeout in sec] = (1999 [reload] + 1) / (32000 [freq] / 4 [prescaler])
        0.25 [timeout in sec] = (2499 [reload] + 1) / (40000 [freq] / 4 [prescaler])