nfc: pn532: Add uart phy docs and rename it

This adds documentation about the uart phy to the pn532 binding doc. As
the filename "pn533-i2c.txt" is not appropriate any more, rename it to
the more general "pn532.txt".
This also documents the deprecation of the compatible strings ending
with "...-i2c".

Cc: Johan Hovold <johan@kernel.org>
Cc: Simon Horman <horms@verge.net.au>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/nfc/pn533-i2c.txt → Documentation/devicetree/bindings/net/nfc/pn532.txt

 * NXP Semiconductors PN532 NFC Controller
 
 Required properties:
-- compatible: Should be "nxp,pn532-i2c" or "nxp,pn533-i2c".
+- compatible: Should be
+    - "nxp,pn532" Place a node with this inside the devicetree node of the bus
+                  where the NFC chip is connected to.
+                  Currently the kernel has phy bindings for uart and i2c.
+    - "nxp,pn532-i2c" (DEPRECATED) only works for the i2c binding.
+    - "nxp,pn533-i2c" (DEPRECATED) only works for the i2c binding.
+
+Required properties if connected on i2c:
 - clock-frequency: I²C work frequency.
-- reg: address on the bus
+- reg: for the I²C bus address. This is fixed at 0x24 for the PN532.
 - interrupts: GPIO interrupt to which the chip is connected
 
 Optional SoC Specific Properties:
@@ -15,9 +22,9 @@ Example (for ARM-based BeagleBone with PN532 on I2C2):
 &i2c2 {
 
 
-	pn532: pn532@24 {
+	pn532: nfc@24 {
 
-		compatible = "nxp,pn532-i2c";
+		compatible = "nxp,pn532";
 
 		reg = <0x24>;
 		clock-frequency = <400000>;
@@ -27,3 +34,13 @@ Example (for ARM-based BeagleBone with PN532 on I2C2):
 
 	};
 };
+
+Example (for PN532 connected via uart):
+
+uart4: serial@49042000 {
+        compatible = "ti,omap3-uart";
+
+        pn532: nfc {
+                compatible = "nxp,pn532";
+        };
+};