[PATCH V2] ethernet: stmmac: support driver work for DTs without child queue node

[jay.xu at rock-chips.com]

Hi, andrew

--------------
jay.xu at rock-chips.com
>On Fri, Apr 29, 2022 at 08:46:05AM +0800, Jianqun Xu wrote:
>> The driver use the value of property 'snps,rx-queues-to-use' to loop
>> same numbers child nodes as queues, such as:
>>
>>     gmac {
>>         rx-queues-config {
>>             snps,rx-queues-to-use = <1>;
>>             queue0 {
>>                 // nothing need here.
>>     };
>> };
>>     };
>>
>> Since a patch for dtc from rockchip will delete all node without any
>> properties or child node, the queue0 node will be deleted, that caused
>> the driver fail to probe:
>
>Is this the in tree dtc? Do you have a commit hash for it? That should
>probably be used as a Fixes: tag. Or that change to dtc needs
>reverting because it breaks stuff.
> 
The patch is a hack patch for some products and have not in tree dtc, I said that to
explain a possible case how things happed, it's only a case of no child queue node.

In my mind, it's hard to understand the one property (snps,rx-queues-to-use) does
have a limit for another nodes or properties, if it must work well, the dtc is better to
do a abort, like #size-cells ?

My personally question from a insigth of DTs but gmac, if it's not a good question,
I can simply add a status = "okay" for the empty node and drop this patch.

>	  Andrew