gpio: mmio: add support for NI 169445 NAND GPIO

The GPIO-based NAND controller on National Instruments 169445 hardware
exposes a set of simple lines for the control signals.

Signed-off-by: Nathan Sullivan <nathan.sullivan@ni.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

2 files changed, 39 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/gpio/ni,169445-nand-gpio.txt b/Documentation/devicetree/bindings/gpio/ni,169445-nand-gpio.txt
new file mode 100644
index 000000000000..ca2f8c745a27
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/ni,169445-nand-gpio.txt
@@ -0,0 +1,38 @@
+Bindings for the National Instruments 169445 GPIO NAND controller
+
+The 169445 GPIO NAND controller has two memory mapped GPIO registers, one
+for input (the ready signal) and one for output (control signals).  It is
+intended to be used with the GPIO NAND driver.
+
+Required properties:
+        - compatible: should be "ni,169445-nand-gpio"
+        - reg-names: must contain
+                "dat" - data register
+        - reg: address + size pairs describing the GPIO register sets;
+                order must correspond with the order of entries in reg-names
+        - #gpio-cells: must be set to 2. The first cell is the pin number and
+                        the second cell is used to specify the gpio polarity:
+                        0 = active high
+                        1 = active low
+        - gpio-controller: Marks the device node as a gpio controller.
+
+Optional properties:
+        - no-output: disables driving output on the pins
+
+Examples:
+        gpio1: nand-gpio-out@1f300010 {
+                compatible = "ni,169445-nand-gpio";
+                reg = <0x1f300010 0x4>;
+                reg-names = "dat";
+                gpio-controller;
+                #gpio-cells = <2>;
+        };
+
+        gpio2: nand-gpio-in@1f300014 {
+                compatible = "ni,169445-nand-gpio";
+                reg = <0x1f300014 0x4>;
+                reg-names = "dat";
+                gpio-controller;
+                #gpio-cells = <2>;
+                no-output;
+        };
diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c
index d7d03ad052d0..f7da40e46c55 100644
--- a/drivers/gpio/gpio-mmio.c
+++ b/drivers/gpio/gpio-mmio.c
@@ -575,6 +575,7 @@ static void __iomem *bgpio_map(struct platform_device *pdev,
 static const struct of_device_id bgpio_of_match[] = {
         { .compatible = "brcm,bcm6345-gpio" },
         { .compatible = "wd,mbl-gpio" },
+        { .compatible = "ni,169445-nand-gpio" },
         { }
 };
 MODULE_DEVICE_TABLE(of, bgpio_of_match);