On Tue, Dec 15, 2020 at 6:44 PM Calvin Johnson
[off-list ref] wrote:

Extract phy_id from compatible string. This will be used by
fwnode_mdiobus_register_phy() to create phy device using the
phy_id.

...

+       if (sscanf(cp, "ethernet-phy-id%4x.%4x", &upper, &lower) == 2) {
+               *phy_id = ((upper & 0xFFFF) << 16) | (lower & 0xFFFF);
+               return 0;
+       }
+       return -EINVAL;

Perhaps traditional pattern, i.e.
       if (sscanf(cp, "ethernet-phy-id%4x.%4x", &upper, &lower) != 2)
               return -EINVAL;

       *phy_id = ((upper & 0xFFFF) << 16) | (lower & 0xFFFF);
       return 0;

And perhaps GENMASK() ?

-- 
With Best Regards,
Andy Shevchenko