pinctrl/gpio: non-linear GPIO ranges accesible from gpiolib

This patch adds the infrastructure required to register non-linear gpio
ranges through gpiolib and the standard GPIO device tree bindings.

Signed-off-by: Christian Ruppert <christian.ruppert@abilis.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 38 insertions, 2 deletions

diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt
index 6cec6ff20d2e..0c85bb6e3a80 100644
--- a/Documentation/devicetree/bindings/gpio/gpio.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio.txt
@@ -87,8 +87,10 @@ controllers. The gpio-ranges property described below represents this, and
 contains information structures as follows:
 
 	gpio-range-list ::= <single-gpio-range> [gpio-range-list]
-	single-gpio-range ::=
+	single-gpio-range ::= <numeric-gpio-range> | <named-gpio-range>
+	numeric-gpio-range ::=
 			<pinctrl-phandle> <gpio-base> <pinctrl-base> <count>
+	named-gpio-range ::= <pinctrl-phandle> <gpio-base> '<0 0>'
 	gpio-phandle : phandle to pin controller node.
 	gpio-base : Base GPIO ID in the GPIO controller
 	pinctrl-base : Base pinctrl pin ID in the pin controller
@@ -97,6 +99,19 @@ contains information structures as follows:
 The "pin controller node" mentioned above must conform to the bindings
 described in ../pinctrl/pinctrl-bindings.txt.
 
+In case named gpio ranges are used (ranges with both <pinctrl-base> and
+<count> set to 0), the property gpio-ranges-group-names contains one string
+for every single-gpio-range in gpio-ranges:
+	gpiorange-names-list ::= <gpiorange-name> [gpiorange-names-list]
+	gpiorange-name : Name of the pingroup associated to the GPIO range in
+			the respective pin controller.
+
+Elements of gpiorange-names-list corresponding to numeric ranges contain
+the empty string. Elements of gpiorange-names-list corresponding to named
+ranges contain the name of a pin group defined in the respective pin
+controller. The number of pins/GPIOs in the range is the number of pins in
+that pin group.
+
 Previous versions of this binding required all pin controller nodes that
 were referenced by any gpio-ranges property to contain a property named
 #gpio-range-cells with value <3>. This requirement is now deprecated.
@@ -104,7 +119,7 @@ However, that property may still exist in older device trees for
 compatibility reasons, and would still be required even in new device
 trees that need to be compatible with older software.
 
-Example:
+Example 1:
 
 	qe_pio_e: gpio-controller@1460 {
 		#gpio-cells = <2>;
@@ -117,3 +132,24 @@ Example:
 Here, a single GPIO controller has GPIOs 0..9 routed to pin controller
 pinctrl1's pins 20..29, and GPIOs 10..19 routed to pin controller pinctrl2's
 pins 50..59.
+
+Example 2:
+
+	gpio_pio_i: gpio-controller@14B0 {
+		#gpio-cells = <2>;
+		compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
+		reg = <0x1480 0x18>;
+		gpio-controller;
+		gpio-ranges =			<&pinctrl1 0 20 10>,
+						<&pinctrl2 10 0 0>,
+						<&pinctrl1 15 0 10>,
+						<&pinctrl2 25 0 0>;
+		gpio-ranges-group-names =	"",
+						"foo",
+						"",
+						"bar";
+	};
+
+Here, three GPIO ranges are defined wrt. two pin controllers. pinctrl1 GPIO
+ranges are defined using pin numbers whereas the GPIO ranges wrt. pinctrl2
+are named "foo" and "bar".