pinctrl: Cygnus: define Broadcom Cygnus GPIO/PINCONF binding

Document the GPIO/PINCONF device tree binding for Broadcom Cygnus SoC

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-gpio.txt b/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-gpio.txt
new file mode 100644 (file)
index 0000000..6540ca5
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+++ b/Documentation/devicetree/bindings/pinctrl/brcm,cygnus-gpio.txt
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+Broadcom Cygnus GPIO/PINCONF Controller
+
+Required properties:
+
+- compatible:
+    Must be "brcm,cygnus-ccm-gpio", "brcm,cygnus-asiu-gpio", or
+    "brcm,cygnus-crmu-gpio"
+
+- reg:
+    Define the base and range of the I/O address space that contains the Cygnus
+GPIO/PINCONF controller registers
+
+- #gpio-cells:
+    Must be two. The first cell is the GPIO pin number (within the
+controller's pin space) and the second cell is used for the following:
+    bit[0]: polarity (0 for active high and 1 for active low)
+
+- gpio-controller:
+    Specifies that the node is a GPIO controller
+
+Optional properties:
+
+- interrupts:
+    Interrupt ID
+
+- interrupt-controller:
+    Specifies that the node is an interrupt controller
+
+- pinmux:
+    Specifies the phandle to the IOMUX device, where pins can be individually
+muxed to GPIO
+
+Supported generic PINCONF properties in child nodes:
+
+- pins:
+    The list of pins (within the controller's own pin space) that properties
+in the node apply to. Pin names are "gpio-<pin>"
+
+- bias-disable:
+    Disable pin bias
+
+- bias-pull-up:
+    Enable internal pull up resistor
+
+- bias-pull-down:
+    Enable internal pull down resistor
+
+- drive-strength:
+    Valid drive strength values include 2, 4, 6, 8, 10, 12, 14, 16 (mA)
+
+Example:
+       gpio_ccm: gpio@1800a000 {
+               compatible = "brcm,cygnus-ccm-gpio";
+               reg = <0x1800a000 0x50>,
+                     <0x0301d164 0x20>;
+               #gpio-cells = <2>;
+               gpio-controller;
+               interrupts = <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>;
+               interrupt-controller;
+
+               touch_pins: touch_pins {
+                       pwr: pwr {
+                               pins = "gpio-0";
+                               drive-strength = <16>;
+                       };
+
+                       event: event {
+                               pins = "gpio-1";
+                               bias-pull-up;
+                       };
+               };
+       };
+
+       gpio_asiu: gpio@180a5000 {
+               compatible = "brcm,cygnus-asiu-gpio";
+               reg = <0x180a5000 0x668>;
+               #gpio-cells = <2>;
+               gpio-controller;
+               interrupts = <GIC_SPI 174 IRQ_TYPE_LEVEL_HIGH>;
+               interrupt-controller;
+       };
+
+       /*
+        * Touchscreen that uses the CCM GPIO 0 and 1
+        */
+       tsc {
+               ...
+               ...
+               gpio-pwr = <&gpio_ccm 0 0>;
+               gpio-event = <&gpio_ccm 1 0>;
+       };
+
+       /* Bluetooth that uses the ASIU GPIO 5, with polarity inverted */
+       bluetooth {
+               ...
+               ...
+               bcm,rfkill-bank-sel = <&gpio_asiu 5 1>
+       }