[U-Boot] [PATCH 2/4 v2] doc: bindings: Add description for MDIO MUX dts nodes
Alexandru Marginean
alexandru.marginean at nxp.com
Tue Jun 18 14:58:02 UTC 2019
More email trouble at my end, please ignore this.
I'll resend as v3 from the nxp account..
Alex
On 6/18/2019 5:47 PM, Alex Marginean wrote:
> Adds a short bindings document describing the expected structure of a MDIO
> MUX dts node. This is based on Linux binding and the example is in fact
> copied from there.
>
> Signed-off-by: Alex Marginean <alexm.osslist at gmail.com>
> ---
>
> Changes in v2:
> - no change
>
> doc/device-tree-bindings/net/mdio-mux.txt | 61 +++++++++++++++++++++++
> 1 file changed, 61 insertions(+)
> create mode 100644 doc/device-tree-bindings/net/mdio-mux.txt
>
> diff --git a/doc/device-tree-bindings/net/mdio-mux.txt b/doc/device-tree-bindings/net/mdio-mux.txt
> new file mode 100644
> index 0000000000..fdf817fd93
> --- /dev/null
> +++ b/doc/device-tree-bindings/net/mdio-mux.txt
> @@ -0,0 +1,61 @@
> +The expected structure of an MDIO MUX device tree node is described here. This
> +is heavily based on current Linux specification.
> +The MDIO buses downstream of the MUX should be described in the device tree as
> +child nodes as indicated below.
> +
> +Required properties:
> +mdio-parent-bus = a phandle to the MDIO bus used to perform actual I/O. This is
> + typically a real MDIO device, unless there are cascaded MUXes.
> +#address-cells = <1>, each MDIO group is identified by one 32b value.
> +#size-cells = <0>
> +
> +Other properties:
> +The properties described here are sufficient for MDIO MUX DM class code, but
> +MUX drivers may define additional properties, either required or optional.
> +
> +Required properties in child nodes:
> +reg = value to be configured on the MUX to select the respective downstream
> + MDIO.
> +
> +Child nodes should normally contain PHY nodes, referenced by phandle from
> +ethernet nodes of the eth interfaces using these PHYs.
> +
> +Example structure, extracted from Linux bindings document:
> +
> + /* The parent MDIO bus. */
> + smi1: mdio at 1180000001900 {
> + compatible = "cavium,octeon-3860-mdio";
> + #address-cells = <1>;
> + #size-cells = <0>;
> + reg = <0x11800 0x00001900 0x0 0x40>;
> + };
> +
> + /*
> + An NXP sn74cbtlv3253 dual 1-of-4 switch controlled by a
> + pair of GPIO lines. Child busses 2 and 3 populated with 4
> + PHYs each.
> + */
> + mdio-mux {
> + compatible = "mdio-mux-gpio";
> + gpios = <&gpio1 3 0>, <&gpio1 4 0>;
> + mdio-parent-bus = <&smi1>;
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + mdio at 2 {
> + reg = <2>;
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + phy11: ethernet-phy at 1 {
> + reg = <1>;
> + marvell,reg-init = <3 0x10 0 0x5777>,
> + <3 0x11 0 0x00aa>,
> + <3 0x12 0 0x4105>,
> + <3 0x13 0 0x0a60>;
> + interrupt-parent = <&gpio>;
> + interrupts = <10 8>; /* Pin 10, active low */
> + };
> + };
> + };
> +
>
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