80 lines · yaml
1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)2%YAML 1.23---4$id: http://devicetree.org/schemas/power/reset/gpio-restart.yaml#5$schema: http://devicetree.org/meta-schemas/core.yaml#6 7title: GPIO controlled reset8 9maintainers:10 - Sebastian Reichel <sre@kernel.org>11 12description: >13 Drive a GPIO line that can be used to restart the system from a restart handler.14 15 This binding supports level and edge triggered reset. At driver load time, the driver will16 request the given gpio line and install a restart handler. If the optional properties17 'open-source' is not found, the GPIO line will be driven in the inactive state. Otherwise its18 not driven until the restart is initiated.19 20 When the system is restarted, the restart handler will be invoked in priority order. The GPIO21 is configured as an output, and driven active, triggering a level triggered reset condition.22 This will also cause an inactive->active edge condition, triggering positive edge triggered23 reset. After a delay specified by active-delay, the GPIO is set to inactive, thus causing an24 active->inactive edge, triggering negative edge triggered reset. After a delay specified by25 inactive-delay, the GPIO is driven active again. After a delay specified by wait-delay, the26 restart handler completes allowing other restart handlers to be attempted.27 28allOf:29 - $ref: restart-handler.yaml#30 31properties:32 compatible:33 const: gpio-restart34 35 gpios:36 description: The GPIO to set high/low, see "gpios property" in37 Documentation/devicetree/bindings/gpio/gpio.txt. If the pin should be low to reset the board38 set it to "Active Low", otherwise set GPIO to "Active High".39 40 open-source:41 $ref: /schemas/types.yaml#/definitions/flag42 description: Treat the GPIO as being open source and defer driving it to when the restart is43 initiated. If this optional property is not specified, the GPIO is initialized as an output44 in its inactive state.45 46 priority:47 default: 12948 49 active-delay:50 $ref: /schemas/types.yaml#/definitions/uint3251 description: Delay (default 100) to wait after driving gpio active [ms]52 default: 10053 54 inactive-delay:55 $ref: /schemas/types.yaml#/definitions/uint3256 description: Delay (default 100) to wait after driving gpio inactive [ms]57 default: 10058 59 wait-delay:60 $ref: /schemas/types.yaml#/definitions/uint3261 description: Delay (default 3000) to wait after completing restart sequence [ms]62 default: 10063 64additionalProperties: false65 66required:67 - compatible68 - gpios69 70examples:71 - |72 gpio-restart {73 compatible = "gpio-restart";74 gpios = <&gpio 4 0>;75 priority = <128>;76 active-delay = <100>;77 inactive-delay = <100>;78 wait-delay = <3000>;79 };80