On 08/24/2012 01:10 PM, Timur Tabi wrote:
> Add support for an MDIO bus multiplexer controlled by a simple memory-mapped
> device, like an FPGA. The device 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.
> +++ b/Documentation/devicetree/bindings/net/mdio-mux-mmioreg.txt
> +Properties for an MDIO bus multiplexer controlled by a memory-mapped device
> +
> +This is a special case of a MDIO bus multiplexer. A memory-mapped device,
> +like an FPGA, is used to control which child bus is connected. The mdio-mux
> +node must be a child of the memory-mapped device. The driver currently only
> +supports devices with eight-bit registers.
That last sentence seems like a property of the driver, not the binding;
I could easily anticipate allowing the size to be 1 or 2 or 4, and a
driver adapter to that in the future.
Otherwise, this binding looks great now.
> +++ b/drivers/net/phy/mdio-mux-mmioreg.c
> +static int mdio_mux_mmioreg_switch_fn(int current_child, int desired_child,
> + void *data)
> +{
> + struct mdio_mux_mmioreg_state *s = data;
> +
> + if (current_child ^ desired_child) {
> + void *p = ioremap(s->phys, 1);
> + uint8_t x, y;
> +
> + if (!p)
> + return -ENOMEM;
Why not map it during probe?
> + x = ioread8(p);
> + y = (x & ~s->mask) | desired_child;
> + if (x != y) {
Isn't that always true, given if (current_child ^ desired_child) above?
> + iowrite8((x & ~s->mask) | desired_child, p);
> + pr_debug("%s: %02x -> %02x\n", __func__, x, y);
> + }
> +
> + iounmap(p);
> + }
> +
> + return 0;
> +}
_______________________________________________
devicetree-discuss mailing list
[email protected]
https://lists.ozlabs.org/listinfo/devicetree-discuss
