This adds device tree bindings of the restart driver for power managing micro controller units that are connected to a board via the UART interface.
Signed-off-by: Evgeny Kolesnikov <[email protected]> --- .../bindings/power/reset/uart-restart.txt | 39 +++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 Documentation/devicetree/bindings/power/reset/uart-restart.txt diff --git a/Documentation/devicetree/bindings/power/reset/uart-restart.txt b/Documentation/devicetree/bindings/power/reset/uart-restart.txt new file mode 100644 index 000000000000..bf831d9bdff8 --- /dev/null +++ b/Documentation/devicetree/bindings/power/reset/uart-restart.txt @@ -0,0 +1,39 @@ +* UART-based PM MCU restart driver + +Some devices have a microcontroller controlling the main power +supply. This microcontroller is connected to UART of the SoC. +Sending a sequence of characters tells the MCU to reset the SoC +and/or MCU itself. + +The length of the sequence, baud rate and the timeout to process +the command may vary from device to device. + +This driver could be used for WD My Cloud (Marvell SoCs), QNAP +(Kirkwood and Orion5x SoCs) and Synology NAS devices. + +Required properties: +- compatible: Should be "uart-restart" +- reg: Address and length of the register set for UART +- clocks: The tclk clock +- cmd: Array of bytes, the command to send to the MCU +- baud: Baud rate [75..460800] + +Optional properties: +- byte-delay: A delay after each byte of a command, could be useful + for sloppy MCUs [ms], default value is 5 +- timeout: A timeout to wait for the MCU to process the command [ms], + default value is 1000 +- override: Boolean flag that indicates if the driver should + prioritize itself over any existing restart driver, + default behaviour is not to interfere + +Example: + restart@12100 { + compatible = "uart-restart"; + reg = <0x12100 0x100>; + clocks = <&coreclk 0>; + baud = <19200>; + cmd = [fa 03 03 02 00 00 fb]; + override; + status = "okay"; + }; -- 2.21.0
