dt: binding: reword PowerPC 8xxx GPIO documentation

re-format and re-word the device tree binding documentation for MPC8xxx
and compatibles, reference the common document for interrupt controllers
and remove outdated duplicate SoC specific information

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <Pawel.Moll@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: <devicetree@vger.kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Gerhard Sittig <gsi@denx.de>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>

1 files changed, 40 insertions, 26 deletions

diff --git a/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt b/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt
index b0019eb5330e..798cfc9d3839 100644
--- a/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt
+++ b/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt
@@ -5,16 +5,42 @@ This is for the non-QE/CPM/GUTs GPIO controllers as found on
 
 Every GPIO controller node must have #gpio-cells property defined,
 this information will be used to translate gpio-specifiers.
+See bindings/gpio/gpio.txt for details of how to specify GPIO
+information for devices.
+
+The GPIO module usually is connected to the SoC's internal interrupt
+controller, see bindings/interrupt-controller/interrupts.txt (the
+interrupt client nodes section) for details how to specify this GPIO
+module's interrupt.
+
+The GPIO module may serve as another interrupt controller (cascaded to
+the SoC's internal interrupt controller).  See the interrupt controller
+nodes section in bindings/interrupt-controller/interrupts.txt for
+details.
 
 Required properties:
-- compatible : "fsl,<CHIP>-gpio" followed by "fsl,mpc8349-gpio" for
-  83xx, "fsl,mpc8572-gpio" for 85xx and "fsl,mpc8610-gpio" for 86xx.
-- #gpio-cells : Should be two. The first cell is the pin number and the
-  second cell is used to specify optional parameters (currently unused).
- - interrupts : Interrupt mapping for GPIO IRQ.
- - interrupt-parent : Phandle for the interrupt controller that
-   services interrupts for this device.
-- gpio-controller : Marks the port as GPIO controller.
+- compatible:           "fsl,<chip>-gpio" followed by "fsl,mpc8349-gpio"
+                        for 83xx, "fsl,mpc8572-gpio" for 85xx, or
+                        "fsl,mpc8610-gpio" for 86xx.
+- #gpio-cells:          Should be two. The first cell is the pin number
+                        and the second cell is used to specify optional
+                        parameters (currently unused).
+- interrupt-parent:     Phandle for the interrupt controller that
+                        services interrupts for this device.
+- interrupts:           Interrupt mapping for GPIO IRQ.
+- gpio-controller:      Marks the port as GPIO controller.
+
+Optional properties:
+- interrupt-controller: Empty boolean property which marks the GPIO
+                        module as an IRQ controller.
+- #interrupt-cells:     Should be two.  Defines the number of integer
+                        cells required to specify an interrupt within
+                        this interrupt controller.  The first cell
+                        defines the pin number, the second cell
+                        defines additional flags (trigger type,
+                        trigger polarity).  Note that the available
+                        set of trigger conditions supported by the
+                        GPIO module depends on the actual SoC.
 
 Example of gpio-controller nodes for a MPC8347 SoC:
 
@@ -22,39 +48,27 @@ Example of gpio-controller nodes for a MPC8347 SoC:
                 #gpio-cells = <2>;
                 compatible = "fsl,mpc8347-gpio", "fsl,mpc8349-gpio";
                 reg = <0xc00 0x100>;
-                interrupts = <74 0x8>;
                 interrupt-parent = <&ipic>;
+                interrupts = <74 0x8>;
                 gpio-controller;
+                interrupt-controller;
+                #interrupt-cells = <2>;
         };
 
         gpio2: gpio-controller@d00 {
                 #gpio-cells = <2>;
                 compatible = "fsl,mpc8347-gpio", "fsl,mpc8349-gpio";
                 reg = <0xd00 0x100>;
-                interrupts = <75 0x8>;
                 interrupt-parent = <&ipic>;
+                interrupts = <75 0x8>;
                 gpio-controller;
         };
 
-See booting-without-of.txt for details of how to specify GPIO
-information for devices.
-
-To use GPIO pins as interrupt sources for peripherals, specify the
-GPIO controller as the interrupt parent and define GPIO number +
-trigger mode using the interrupts property, which is defined like
-this:
-
-interrupts = <number trigger>, where:
- - number: GPIO pin (0..31)
- - trigger: trigger mode:
-        2 = trigger on falling edge
-        3 = trigger on both edges
-
-Example of device using this is:
+Example of a peripheral using the GPIO module as an IRQ controller:
 
         funkyfpga@0 {
                 compatible = "funky-fpga";
                 ...
-                interrupts = <4 3>;
                 interrupt-parent = <&gpio1>;
+                interrupts = <4 3>;
         };