linux/Documentation/devicetree/bindings/net/mdio-gpio.txt
Srinivas Kandagatla 3272dd9b0f of/net/mdio-gpio: Fix pdev->id issue when using devicetrees.
When the mdio-gpio driver is probed via device trees, the platform
device id is set as -1, However the pdev->id is re-used as bus-id for
while creating mdio gpio bus.
So
For device tree case the mdio-gpio bus name appears as "gpio-ffffffff"
where as
for non-device tree case the bus name appears as "gpio-<bus-num>"

Which means the bus_id is fixed in device tree case, so we can't have
two mdio gpio buses via device trees. Assigning a logical bus number
via device tree solves the problem and the bus name is much consistent
with non-device tree bus name.

Without this patch
1. we can't support two mdio-gpio buses via device trees.
2. we should always pass gpio-ffffffff as bus name to phy_connect, very
different to non-device tree bus name.

So, setting up the bus_id via aliases from device tree is the right
solution and other drivers do similar thing.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-19 18:57:07 -05:00

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MDIO on GPIOs
Currently defined compatibles:
- virtual,gpio-mdio
MDC and MDIO lines connected to GPIO controllers are listed in the
gpios property as described in section VIII.1 in the following order:
MDC, MDIO.
Note: Each gpio-mdio bus should have an alias correctly numbered in "aliases"
node.
Example:
aliases {
mdio-gpio0 = <&mdio0>;
};
mdio0: mdio {
compatible = "virtual,mdio-gpio";
#address-cells = <1>;
#size-cells = <0>;
gpios = <&qe_pio_a 11
&qe_pio_c 6>;
};