of_net: Implement of_get_nvmem_mac_address helper

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.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/of_net.h b/include/linux/of_net.h
index 9cd72aab76fe..90d81ee9e6a0 100644
--- a/include/linux/of_net.h
+++ b/include/linux/of_net.h
@@ -13,6 +13,7 @@
 struct net_device;
 extern int of_get_phy_mode(struct device_node *np);
 extern const void *of_get_mac_address(struct device_node *np);
+extern int of_get_nvmem_mac_address(struct device_node *np, void *addr);
 extern struct net_device *of_find_net_device_by_node(struct device_node *np);
 #else
 static inline int of_get_phy_mode(struct device_node *np)
@@ -25,6 +26,11 @@ static inline const void *of_get_mac_address(struct device_node *np)
 	return NULL;
 }
 
+static inline int of_get_nvmem_mac_address(struct device_node *np, void *addr)
+{
+	return -ENODEV;
+}
+
 static inline struct net_device *of_find_net_device_by_node(struct device_node *np)
 {
 	return NULL;