On 09/17/2018 09:47 AM, Wang, Dongsheng wrote:
> On 9/17/2018 10:50 PM, Andrew Lunn wrote:
>> On Mon, Sep 17, 2018 at 04:53:29PM +0800, Wang Dongsheng wrote:
>>> This property copy from "ibm,emac.txt" to describe a shared MIDO bus.
>>> Since emac include MDIO, so If the motherboard has more than one PHY
>>> connected to an MDIO bus, this property will point to the MAC device
>>> that has the MDIO bus.
>>>
>>> Signed-off-by: Wang Dongsheng <dongsheng.wang@xxxxxxxxxxxxxxxx>
>>> ---
>>> V2: s/Since QDF2400 emac/Since emac/
>>> ---
>>> Documentation/devicetree/bindings/net/qcom-emac.txt | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/net/qcom-emac.txt b/Documentation/devicetree/bindings/net/qcom-emac.txt
>>> index 346e6c7f47b7..50db71771358 100644
>>> --- a/Documentation/devicetree/bindings/net/qcom-emac.txt
>>> +++ b/Documentation/devicetree/bindings/net/qcom-emac.txt
>>> @@ -24,6 +24,9 @@ Internal PHY node:
>>> The external phy child node:
>>> - reg : The phy address
>>>
>>> +Optional properties:
>>> +- mdio-device : Shared MIDO bus.
>> Hi Dongsheng
>>
>> I don't see why you need this property. The ethernet interface has a
>> phy-handle which points to a PHY. That is all you need to find the PHY.
> phy-handle is description PHY address. This property is describing an
> MDIO controller.
> Each QCOM emac include an MDIO controller, normally each emac only
> connect one
> PHY device, but when all of the PHY devices mdio lines connect one MDIO
> controller
> that is included in EMAC, we need to share this MDIO controller for
> others EMAC.
If you want to describe the MDIO controller, then you embed a mdio
subnode into your Ethernet MAC node:
emac0: ethernet@feb20000 {
mdio {
#address-cells = <1>;
#size-cells = <0>;
phy0: ethernet-phy@0 {
reg = <0>;
};
};
};
And then each Ethernet MAC controller refers to their appropriate PHY
device tree node using a phy-handle property to point to either their
own MDIO controller, or another MAC's MDIO controller.
The IBM Emac is a old (not to say bad) example and it does not use the
PHY library and the standard Device Tree node property, please don't use
it as a reference.
--
Florian
