linux/Documentation/devicetree/bindings/bus/moxtet.txt
Marek Behún 20e6cf7e74 dt-bindings: bus: Document moxtet bus binding
This adds device tree binding documentation for the Moxtet bus, a bus
via which the different modules connected to the Turris Mox router can
be configured.

Link: https://lore.kernel.org/r/20190812161118.21476-3-marek.behun@nic.cz
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-08-14 15:30:43 +02:00

47 lines
1.3 KiB
Plaintext

Turris Mox module status and configuration bus (over SPI)
Required properties:
- compatible : Should be "cznic,moxtet"
- #address-cells : Has to be 1
- #size-cells : Has to be 0
- spi-cpol : Required inverted clock polarity
- spi-cpha : Required shifted clock phase
- interrupts : Must contain reference to the shared interrupt line
- interrupt-controller : Required
- #interrupt-cells : Has to be 1
For other required and optional properties of SPI slave nodes please refer to
../spi/spi-bus.txt.
Required properties of subnodes:
- reg : Should be position on the Moxtet bus (how many Moxtet
modules are between this module and CPU module, so
either 0 or a positive integer)
The driver finds the devices connected to the bus by itself, but it may be
needed to reference some of them from other parts of the device tree. In that
case the devices can be defined as subnodes of the moxtet node.
Example:
moxtet@1 {
compatible = "cznic,moxtet";
#address-cells = <1>;
#size-cells = <0>;
reg = <1>;
spi-max-frequency = <10000000>;
spi-cpol;
spi-cpha;
interrupt-controller;
#interrupt-cells = <1>;
interrupt-parent = <&gpiosb>;
interrupts = <5 IRQ_TYPE_EDGE_FALLING>;
moxtet_sfp: gpio@0 {
compatible = "cznic,moxtet-gpio";
gpio-controller;
#gpio-cells = <2>;
reg = <0>;
}
};