Merge branch 'Implement-of_get_nvmem_mac_address-helper'

Mike Looijmans says:

====================
of_net: Implement of_get_nvmem_mac_address helper

Posted this as a small set now, with an (optional) second patch that shows
how the changes work and what I've used to test the code on a Topic Miami board.
I've taken the liberty to add appropriate "Acked" and "Review" tags.

v4: Replaced "6" with ETH_ALEN

v3: Add patch that implements mac in nvmem for the Cadence MACB controller
    Remove the integrated of_get_mac_address call

v2: Use of_nvmem_cell_get to avoid needing the assiciated device
    Use void* instead of char*
    Add devicetree binding doc
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 57 insertions, 3 deletions

diff --git a/Documentation/devicetree/bindings/net/ethernet.txt b/Documentation/devicetree/bindings/net/ethernet.txt
index 2974e63ba311..cfc376bc977a 100644
--- a/Documentation/devicetree/bindings/net/ethernet.txt
+++ b/Documentation/devicetree/bindings/net/ethernet.txt
@@ -10,6 +10,8 @@ Documentation/devicetree/bindings/phy/phy-bindings.txt.
   the boot program; should be used in cases where the MAC address assigned to
   the device by the boot program is different from the "local-mac-address"
   property;
+- nvmem-cells: phandle, reference to an nvmem node for the MAC address;
+- nvmem-cell-names: string, should be "mac-address" if nvmem is to be used;
 - max-speed: number, specifies maximum speed in Mbit/s supported by the device;
 - max-frame-size: number, maximum transfer unit (IEEE defined MTU), rather than
   the maximum frame size (there's contradiction in the Devicetree
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index d09bd43680b3..b4c9268100bb 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -3952,10 +3952,16 @@ static int macb_probe(struct platform_device *pdev)
                 dev->max_mtu = ETH_DATA_LEN;
 
         mac = of_get_mac_address(np);
-        if (mac)
+        if (mac) {
                 ether_addr_copy(bp->dev->dev_addr, mac);
-        else
-                macb_get_hwaddr(bp);
+        } else {
+                err = of_get_nvmem_mac_address(np, bp->dev->dev_addr);
+                if (err) {
+                        if (err == -EPROBE_DEFER)
+                                goto err_out_free_netdev;
+                        macb_get_hwaddr(bp);
+                }
+        }
 
         err = of_get_phy_mode(np);
         if (err < 0) {
diff --git a/drivers/of/of_net.c b/drivers/of/of_net.c
index d820f3edd431..53189d4022a6 100644
--- a/drivers/of/of_net.c
+++ b/drivers/of/of_net.c
@@ -7,6 +7,7 @@
  */
 #include <linux/etherdevice.h>
 #include <linux/kernel.h>
+#include <linux/nvmem-consumer.h>
 #include <linux/of_net.h>
 #include <linux/phy.h>
 #include <linux/export.h>
@@ -80,3 +81,42 @@ const void *of_get_mac_address(struct device_node *np)
         return of_get_mac_addr(np, "address");
 }
 EXPORT_SYMBOL(of_get_mac_address);
+
+/**
+ * Obtain the MAC address from an nvmem provider named 'mac-address' through
+ * device tree.
+ * On success, copies the new address into memory pointed to by addr and
+ * returns 0. Returns a negative error code otherwise.
+ * @np:         Device tree node containing the nvmem-cells phandle
+ * @addr:       Pointer to receive the MAC address using ether_addr_copy()
+ */
+int of_get_nvmem_mac_address(struct device_node *np, void *addr)
+{
+        struct nvmem_cell *cell;
+        const void *mac;
+        size_t len;
+        int ret;
+
+        cell = of_nvmem_cell_get(np, "mac-address");
+        if (IS_ERR(cell))
+                return PTR_ERR(cell);
+
+        mac = nvmem_cell_read(cell, &len);
+
+        nvmem_cell_put(cell);
+
+        if (IS_ERR(mac))
+                return PTR_ERR(mac);
+
+        if (len < ETH_ALEN || !is_valid_ether_addr(mac)) {
+                ret = -EINVAL;
+        } else {
+                ether_addr_copy(addr, mac);
+                ret = 0;
+        }
+
+        kfree(mac);
+
+        return ret;
+}
+EXPORT_SYMBOL(of_get_nvmem_mac_address);
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;