Re: [PATCH v4 1/2] dt-bindings: net: add MDIO bus multiplexer driven by a regmap device

[Andrew Lunn <andrew@lunn.ch>]

On Wed, Feb 06, 2019 at 06:20:39AM +0000, Pankaj Bansal wrote:
> Add support for an MDIO bus multiplexer controlled by a regmap
> device, like an FPGA.
> 
> Tested on a NXP LX2160AQDS board which uses the "QIXIS" FPGA
> attached to the i2c bus.
> 
> Signed-off-by: Pankaj Bansal <pankaj.bansal@nxp.com>
> ---
> 
> Notes:
>     V4:
>     - No change
>     V3:
>     - No change
>     V2:
>     - New file describing the device tree bindings for regmap controlled devices'
>       mdio mux
> 
>  .../bindings/net/mdio-mux-regmap.txt         | 167 +++++++++++++++++
>  1 file changed, 167 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/net/mdio-mux-regmap.txt b/Documentation/devicetree/bindings/net/mdio-mux-regmap.txt
> new file mode 100644
> index 000000000000..8968f317965f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/mdio-mux-regmap.txt
> @@ -0,0 +1,167 @@
> +Properties for an MDIO bus multiplexer controlled by a regmap
> +
> +This is a special case of a MDIO bus multiplexer.  A regmap device,
> +like an FPGA, is used to control which child bus is connected.  The mdio-mux
> +node must be a child of the device that is controlled by a regmap.
> +The driver currently only supports devices with upto 32-bit registers.
> +
> +Required properties in addition to the generic multiplexer properties:
> +
> +- reg : integer, contains the offset of the register that controls the bus
> +	multiplexer. it can be 32 bit number.
> +
> +- mux-mask : integer, contains an 32 bit mask that specifies which
> +	bits in the register control the actual bus multiplexer.  The
> +	'reg' property of each child mdio-mux node must be constrained by
> +	this mask.

Hi Pankaj

Maybe you can address the comment about not having a compatible flag
by commenting that this is a device tree fragment, which is expected
to appear inside the binding of some other device. It is not a
standalone device.

	   Andrew