Am 2021-04-06 00:13, schrieb Andrew Lunn:
On Mon, Apr 05, 2021 at 11:46:04PM +0200, Michael Walle wrote:
Hi Andrew,
Am 2021-04-05 23:34, schrieb Andrew Lunn:
> > -static int of_get_mac_addr_nvmem(struct device_node *np, 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;
> > + }
>
> Can you think of any odd corner case where nvmem_get_mac_address()
> would fail, but of_nvmem_cell_get(np, "mac-address") would work?
You mean, it might make sense to just return here when
nvmem_get_mac_address() will succeed and fall back to the
of_nvmem_cell_get() in case of an error?
I've not read the documentation for nvmem_get_mac_address(). I was
thinking we might want to return real errors, and -EPROBE_DEFER.
I can't follow, nvmem_get_mac_address() should already return those.
But maybe with -ENODEV we should try of_nvmem_cell_get()?
And if this happens - that is nvmem_get_mac_address(&pdev->dev) returns
-ENODEV - then of_nvmem_cell_get(np) will also return -ENODEV.
Because pdev->dev.of_node == np and nvmem_get_mac_address(&pdev->dev)
tries of_nvmem_cell_get(pdev->dev.of_node) first.
But i'm not sure if there are any real use cases? The only thing i can
think of is if np points to something deeper inside the device tree
than what pdev does?
But then pdev will be NULL and nvmem_get_mac_address() won't be called
at all, no?
-michael
