Subject: Re: [PATCH v2] of_net: Implement of_get_nvmem_mac_address helper

From: Andrew Lunn <[email-masked]>
Date: Mon, 26 Mar 2018 17:50:10 +0200

On Mon, Mar 26, 2018 at 08:41:29AM +0200, Mike Looijmans wrote:
> It's common practice to store MAC addresses for network interfaces into
> nvmem devices. However the code to actually do this in the kernel lacks,
> so this patch adds of_get_nvmem_mac_address() for drivers to obtain the
> address from an nvmem cell provider.
> 
> This is particulary useful on devices where the ethernet interface cannot
> be configured by the bootloader, for example because it's in an FPGA.
> 
> Tested by adapting the cadence macb driver to call this instead of
> of_get_mac_address().

Hi Mike

I can understand you not wanting to modify all the call sites for
of_get_mac_address().

However, the name of_get_nvmem_mac_address() suggests it gets the MAC
address from NVMEM. I think people are going to be surprised when they
find it first tries for a MAC address directly in device tree. I would
drop the call to of_get_mac_address(), and have the MAC driver call
both.

You could also maybe take a look at fwnode_get_mac_address(). It
should work for both OF and ACPI. It fits better because is passes a
char * for the address. You could make that do both, and call it from
the macb driver. dev_fwnode() probably does what you want.

    Andrew