pinctrl: DT: extend the pinmux property to support integers array

Some platforms may need more than one integer to represent a complete
pinmux binding, so let's extend the pinmux property to allow to accept
integer array instead of only a single integer.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: Shawn Guo <shawnguo@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

@@ -204,21 +204,22 @@ each single pin the number of required sub-nodes containing "pin" and
 maintain.
 
 For cases like this, the pin controller driver may use the pinmux helper
-property, where the pin identifier is packed with mux configuration settings
-in a single integer.
+property, where the pin identifier is provided with mux configuration settings
+in a pinmux group. A pinmux group consists of the pin identifier and mux
+settings represented as a single integer or an array of integers.
 
-The pinmux property accepts an array of integers, each of them describing
+The pinmux property accepts an array of pinmux groups, each of them describing
 a single pin multiplexing configuration.
 
 pincontroller {
 	state_0_node_a {
-		pinmux = <PIN_ID_AND_MUX>, <PIN_ID_AND_MUX>, ...;
+		pinmux = <PINMUX_GROUP>, <PINMUX_GROUP>, ...;
 	};
 };
 
 Each individual pin controller driver bindings documentation shall specify
-how those values (pin IDs and pin multiplexing configuration) are defined and
-assembled together.
+how pin IDs and pin multiplexing configuration are defined and assembled
+together in a pinmux group.
 
 == Generic pin configuration node content ==
 
@@ -306,7 +307,7 @@ arguments are described below.
 - pinmux takes a list of pin IDs and mux settings as required argument. The
   specific bindings for the hardware defines:
   - How pin IDs and mux settings are defined and assembled together in a single
-    integer.
+    integer or an array of integers.
 
 - bias-pull-up, -down and -pin-default take as optional argument on hardware
   supporting it the pull strength in Ohm. bias-disable will disable the pull.