lkml.org 
[lkml]   [2019]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH RESEND net] net: phy: xgmiitorgmii: Support generic PHY status read
From
Date
On 11. 03. 19 13:27, Harini Katakam wrote:
> Hi Andrew,
> On Mon, Mar 11, 2019 at 11:34 AM Harini Katakam <harinik@xilinx.com> wrote:
>>
>> Hi Andrew,
>> On Sat, Mar 9, 2019 at 9:53 PM Andrew Lunn <andrew@lunn.ch> wrote:
>>>
>>>> Related to this, I have a query on how the DT node for gmii2rgmii should look.
>>>> One of the users of gmii2rgmii is Cadence macb driver. In Xilinx tree, we use
>>>> this piece of code to register this mdiobus:
>>>> + mdio_np = of_get_child_by_name(np, "mdio");
>>>> + if (mdio_np) {
>>>> + of_node_put(mdio_np);
>>>> + err = of_mdiobus_register(bp->mii_bus, mdio_np);
>>>> + if (err)
>>>> + goto err_out_unregister_bus;
>>>>
>>>> And the DT node looks like this:
>>>> ethernet {
>>>> phy-mode = "gmii";
>>>> phy-handle = <&extphy>;
>>>>
>>>> mdio {
>>>> extphy {
>>>> reg = <x>;
>>>> };
>>>> gmii_to_rgmii{
>>>> compatible = "xlnx,gmii-to-rgmii-1.0";
>>>> phy-handle = <&extphy>;
>>>> reg = <x>;
>>>> };
>>>> };
>>>> };
>>>
>>> Hi Harini
>>>
>>> You have this setup:
>>>
>>> MAC <==> GMII2RGMII <==> RGMII_PHY
>>>
>>> So you want the MAC phy-handle to point to the gmii_to_rgmii 'PHY'.
>>>
>>> Feel free to submit a patch extending
>>> Documentation/devicetree/bindings/net/xilinx_gmii2rgmii.txt to include
>>> a MAC node, etc.
>>
>> Thank you, will do the same.
>
> Thanks again for your input. So, I did some testing with this change.
> But the issue is that, if I point the phy-handle to gmi2rgmii,
> of_phy_connect will be called from the MAC and it will fail because gmii2rgmii
> is not a PHY driver and it does not have a standard PHY register set or ID.
> Which goes back to the discussion above whether this needs to changed in the IP.
>
> But right now, it is a bridge device on the MDIO bus and has no PHY
> functionality.
> Moreover, any MAC is capable of accessing the external PHY with no interference
> in the MDIO path (the gmii2rgmii bridge just acts like another device
> on a common bus).
>
> What Michal suggested below in uboot is that they register gmii2rgmii
> with a dummy
> PHY ID and then attach the external phy driver in its probe. I'm not
> sure if this will work
> in linux i.e. calling phy_connect_direct inside the gmii2rgmii probe.

In u-boot behavior and wiring is similar to fixed-link phy.

Thanks,
Michal

\
 
 \ /
  Last update: 2019-03-11 13:52    [W:0.068 / U:5.212 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site