leds: netxbig: add device tree binding

This patch adds device tree support for the netxbig LEDs.

This also introduces a additionnal DT binding for the GPIO extension bus
(netxbig-gpio-ext) used to configure the LEDs. Since this bus could also
be used to control other devices, then it seems more suitable to have it
in a separate DT binding.

Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

Documentation/devicetree/bindings/gpio/netxbig-gpio-ext.txt

@@ -0,0 +1,22 @@
+Binding for the GPIO extension bus found on some LaCie/Seagate boards
+(Example: 2Big/5Big Network v2, 2Big NAS).
+
+Required properties:
+- compatible: "lacie,netxbig-gpio-ext".
+- addr-gpios: GPIOs representing the address register (LSB -> MSB).
+- data-gpios: GPIOs representing the data register (LSB -> MSB).
+- enable-gpio: latches the new configuration (address, data) on raising edge.
+
+Example:
+
+netxbig_gpio_ext: netxbig-gpio-ext {
+	compatible = "lacie,netxbig-gpio-ext";
+
+	addr-gpios = <&gpio1 15 GPIO_ACTIVE_HIGH
+		      &gpio1 16 GPIO_ACTIVE_HIGH
+		      &gpio1 17 GPIO_ACTIVE_HIGH>;
+	data-gpios = <&gpio1 12 GPIO_ACTIVE_HIGH
+		      &gpio1 13 GPIO_ACTIVE_HIGH
+		      &gpio1 14 GPIO_ACTIVE_HIGH>;
+	enable-gpio = <&gpio0 29 GPIO_ACTIVE_HIGH>;
+};

Documentation/devicetree/bindings/leds/leds-netxbig.txt

@@ -0,0 +1,92 @@
+Binding for the CPLD LEDs (GPIO extension bus) found on some LaCie/Seagate
+boards (Example: 2Big/5Big Network v2, 2Big NAS).
+
+Required properties:
+- compatible: "lacie,netxbig-leds".
+- gpio-ext: Phandle for the gpio-ext bus.
+
+Optional properties:
+- timers: Timer array. Each timer entry is represented by three integers:
+  Mode (gpio-ext bus), delay_on and delay_off.
+
+Each LED is represented as a sub-node of the netxbig-leds device.
+
+Required sub-node properties:
+- mode-addr: Mode register address on gpio-ext bus.
+- mode-val: Mode to value mapping. Each entry is represented by two integers:
+  A mode and the corresponding value on the gpio-ext bus.
+- bright-addr: Brightness register address on gpio-ext bus.
+- max-brightness: Maximum brightness value.
+
+Optional sub-node properties:
+- label: Name for this LED. If omitted, the label is taken from the node name.
+- linux,default-trigger: Trigger assigned to the LED.
+
+Example:
+
+netxbig-leds {
+	compatible = "lacie,netxbig-leds";
+
+	gpio-ext = &gpio_ext;
+
+	timers = <NETXBIG_LED_TIMER1 500 500
+		  NETXBIG_LED_TIMER2 500 1000>;
+
+	blue-power {
+		label = "netxbig:blue:power";
+		mode-addr = <0>;
+		mode-val = <NETXBIG_LED_OFF 0
+			    NETXBIG_LED_ON 1
+			    NETXBIG_LED_TIMER1 3
+			    NETXBIG_LED_TIMER2 7>;
+		bright-addr = <1>;
+		max-brightness = <7>;
+	};
+	red-power {
+		label = "netxbig:red:power";
+		mode-addr = <0>;
+		mode-val = <NETXBIG_LED_OFF 0
+			    NETXBIG_LED_ON 2
+			    NETXBIG_LED_TIMER1 4>;
+		bright-addr = <1>;
+		max-brightness = <7>;
+	};
+	blue-sata0 {
+		label = "netxbig:blue:sata0";
+		mode-addr = <3>;
+		mode-val = <NETXBIG_LED_OFF 0
+			    NETXBIG_LED_ON 7
+			    NETXBIG_LED_SATA 1
+			    NETXBIG_LED_TIMER1 3>;
+		bright-addr = <2>;
+		max-brightness = <7>;
+	};
+	red-sata0 {
+		label = "netxbig:red:sata0";
+		mode-addr = <3>;
+		mode-val = <NETXBIG_LED_OFF 0
+			    NETXBIG_LED_ON 2
+			    NETXBIG_LED_TIMER1 4>;
+		bright-addr = <2>;
+		max-brightness = <7>;
+	};
+	blue-sata1 {
+		label = "netxbig:blue:sata1";
+		mode-addr = <4>;
+		mode-val = <NETXBIG_LED_OFF 0
+			    NETXBIG_LED_ON 7
+			    NETXBIG_LED_SATA 1
+			    NETXBIG_LED_TIMER1 3>;
+		bright-addr = <2>;
+		max-brightness = <7>;
+	};
+	red-sata1 {
+		label = "netxbig:red:sata1";
+		mode-addr = <4>;
+		mode-val = <NETXBIG_LED_OFF 0
+			    NETXBIG_LED_ON 2
+			    NETXBIG_LED_TIMER1 4>;
+		bright-addr = <2>;
+		max-brightness = <7>;
+	};
+};