[PATCH] netdev/phy: add MDIO bus multiplexer driven by a memory-mapped FPGA
David Daney
ddaney.cavm at gmail.com
Thu Aug 23 08:24:05 EST 2012
On 08/22/2012 02:45 PM, Timur Tabi wrote:
> An FPGA controls which sub-bus is connected to the master MDIO bus. The
> FPGA must be memory-mapped and contain only 8-bit registers (which keeps
> things simple).
>
> Tested on a Freescale P5020DS board which uses the "PIXIS" FPGA attached
> to the localbus.
>
> Signed-off-by: Timur Tabi <timur at freescale.com>
> ---
> .../devicetree/bindings/net/mdio-mux-fpga.txt | 74 ++++++++
> drivers/net/phy/Kconfig | 13 ++
> drivers/net/phy/Makefile | 1 +
> drivers/net/phy/mdio-mux-fpga.c | 186 ++++++++++++++++++++
I am fine with the general concept of the patch, so I am going to start
a Bike Shedding session with it over the names of some of the things here.
I wonder if *fpga is really a good name for this. It is a general
purpose multiplexer with a memory mapped control register. I would call
it something like mdio-mux-mmioreg.
> 4 files changed, 274 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/net/mdio-mux-fpga.txt
> create mode 100644 drivers/net/phy/mdio-mux-fpga.c
>
> diff --git a/Documentation/devicetree/bindings/net/mdio-mux-fpga.txt b/Documentation/devicetree/bindings/net/mdio-mux-fpga.txt
> new file mode 100644
> index 0000000..ef567c6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/mdio-mux-fpga.txt
> @@ -0,0 +1,74 @@
> +Properties for an MDIO bus multiplexer/switch controlled by an FPGA register.
> +
> +This is a special case of a MDIO bus multiplexer. An FPGA register is used
> +to control which child bus is connected.
> +
> +Required properties in addition to the generic multiplexer properties:
> +
> +- compatible : string, must contain "mdio-mux-fpga"
> +
> +- mdio-mux-device : phandle, points to the FPGA (or similar) node. This
> + must be a memory-mapped device with 8-bit registers.
You shouldn't need this. Just make the multiplexer a child of FPGA node
to indicate where it lives.
> +
> +- mdio-mux-register : integer, contains the offset of the register that
> + controls the bus multiplexer.
This should just be the normal "reg" properly
> +
> +- mdio-mux-mask : integer, contains an 8-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.
> +
"reg-mask" ??
Do you need a shift too?
David Daney
More information about the devicetree-discuss
mailing list