This is currently supported in firmware deployed on oak, hana and elm mt8173 chromebook devices. The kernel driver is written to be a generic SMC watchdog driver. Arm Trusted Firmware upstreaming review: https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/3405 Patch to add oak, hana, elm device tree: https://lore.kernel.org/linux-arm-kernel/20200110073730.213789-1-hsinyi@xxxxxxxxxxxx/ I would like to add the device tree support after the above patch is accepted. Evan Benn (1): dt-bindings: watchdog: Add arm,smc-wdt watchdog arm,smc-wdt compatible Julius Werner (1): watchdog: Add new arm_smc_wdt watchdog driver .../bindings/watchdog/arm,smc-wdt.yaml | 30 +++ MAINTAINERS | 7 + arch/arm64/configs/defconfig | 1 + drivers/watchdog/Kconfig | 12 ++ drivers/watchdog/Makefile | 1 + drivers/watchdog/arm_smc_wdt.c | 191 ++++++++++++++++++ 6 files changed, 242 insertions(+) create mode 100644 Documentation/devicetree/bindings/watchdog/arm,smc-wdt.yaml create mode 100644 drivers/watchdog/arm_smc_wdt.c -- 2.25.0.265.gbab2e86ba0-goog