Am 2021-04-16 17:19, schrieb Rob Herring:
On Fri, Apr 16, 2021 at 2:30 AM Michael Walle <michael@xxxxxxxx> wrote:
Am 2021-04-16 05:24, schrieb Benjamin Herrenschmidt:
> On Mon, 2021-04-12 at 19:47 +0200, Michael Walle wrote:
>>
>> /**
>> * of_get_phy_mode - Get phy mode for given device_node
>> @@ -59,15 +60,39 @@ static int of_get_mac_addr(struct device_node *np,
>> const char *name, u8 *addr)
>> static int of_get_mac_addr_nvmem(struct device_node *np, u8 *addr)
>> {
>> struct platform_device *pdev = of_find_device_by_node(np);
>> + struct nvmem_cell *cell;
>> + const void *mac;
>> + size_t len;
>> int ret;
>>
>> - if (!pdev)
>> - return -ENODEV;
>> + /* Try lookup by device first, there might be a
>> nvmem_cell_lookup
>> + * associated with a given device.
>> + */
>> + if (pdev) {
>> + ret = nvmem_get_mac_address(&pdev->dev, addr);
>> + put_device(&pdev->dev);
>> + return ret;
>> + }
>> +
>
> This smells like the wrong band aid :)
>
> Any struct device can contain an OF node pointer these days.
But not all nodes might have an associated device, see DSA for
example.
I believe what Ben is saying and what I said earlier is going from dev
-> OF node is right and OF node -> dev is wrong. If you only have an
OF node, then use an of_* function.
And as the name suggests of_get_mac_address() operates on a node. So
if a driver calls of_get_mac_address() it should work on the node.
What
is wrong IMHO, is that the ethernet drivers where the corresponding
board
has a nvmem_cell_lookup registered is calling
of_get_mac_address(node).
It should rather call eth_get_mac_address(dev) in the first place.
One would need to figure out if there is an actual device (with an
assiciated of_node), then call eth_get_mac_address(dev) and if there
isn't a device call of_get_mac_address(node).
Yes, I think we're all in agreement.
But I don't know if that is easy to figure out. Well, one could start
with just the device where nvmem_cell_lookup is used. Then we could
drop the workaround above.
Start with the ones just passing dev.of_node directly:
$ git grep 'of_get_mac_address(.*of_node)'
[..]
Before I'll try to come up with a patch for this, I'd like to get
your opinion on it.
(1) replacing of_get_mac_address(node) with eth_get_mac_address(dev)
might sometimes lead to confusing comments like in
drivers/net/ethernet/allwinner/sun4i-emac.c:
/* Read MAC-address from DT */
ret = of_get_mac_address(np, ndev->dev_addr);
Do we live with that or should the new name somehow reflect that
it is taken from the device tree.
(2) What do you think of eth_get_mac_address(ndev). That is, the
second argument is missing and ndev->dev_addr is used.
I'm unsure about it. We'd still need a second function for drivers
which don't write ndev->dev_addr directly, but have some custom
logic in between. OTOH it would be like eth_hw_addr_random(ndev).
-michael
