[PATCH v3 1/2] leds: add DT binding for BCM6328 LED controller

["Álvaro Fernández Rojas" <noltari@gmail.com>]

This adds device tree binding documentation for the Broadcom BCM6328 LED controller.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Jonas Gorski <jogo@openwrt.org>
---
 v3: introduce changes suggested by Jacek
 - Revert compatible string to "brcm,bcm6328-leds".
 - Improved description.
 - Renamed normal LEDs to hardware controlled.
 - Explain that LEDs are active high by default on active-low optional property.
 - Properties are now grouped depending on the type of LED and optional requirement.
 - Added more examples to explain hardware controlled LEDs and activity/link selection.
 v2: Introduce changes suggested by Florian and Jonas.
 - Change compatible string to "brcm,bcm6328-leds-ctrl".
 - Make valid LEDs statement more strict.
 - Remove compatible strings from LED subnodes.
 - Clarify that LEDs are active high by default.
 - Add a better description for brcm,link-signal-sources and brcm,activity-signal-sources.

 .../devicetree/bindings/leds/leds-bcm6328.txt      | 311 +++++++++++++++++++++
 1 file changed, 311 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/leds-bcm6328.txt

diff --git a/Documentation/devicetree/bindings/leds/leds-bcm6328.txt b/Documentation/devicetree/bindings/leds/leds-bcm6328.txt
new file mode 100644
index 0000000..6d838f8
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-bcm6328.txt
@@ -0,0 +1,311 @@
+LEDs connected to Broadcom BCM6328 controller
+
+This controller is present on BCM6318, BCM6328, BCM6362 and BCM63268.
+In these SoCs it's possible to control LEDs both as GPIOs or by hardware.
+However, on some devices there are Serial LEDs (LEDs connected to a 74x164
+controller), which can either be controlled by software (exporting the 74x164
+as spi-gpio. See Documentation/devicetree/bindings/gpio/gpio-74x164.txt), or
+by hardware using this driver.
+Some of these Serial LEDs are hardware controlled (e.g. ethernet LEDs) and
+exporting the 74x164 as spi-gpio prevents those LEDs to be hardware
+controlled, so the only chance to keep them working is by using this driver.
+
+BCM6328 LED controller has a HWDIS register, which controls whether a LED
+should be controlled by a hardware signal instead of the MODE register value,
+with 0 meaning hardware control enabled and 1 hardware control disabled. This
+is usually 1:1 for hardware to LED signals, but through the activity/link
+registers you have some limited control over rerouting the LEDs (as
+explained later in brcm,link-signal-sources). Even if a LED is hardware
+controlled you are still able to make it blink or light it up if it isn't,
+but you can't turn it off if the hardware decides to light it up. For this
+reason, hardware controlled LEDs aren't registered as LED class devices.
+
+Required properties:
+- compatible: should be : "brcm,bcm6328-leds".
+- #address-cells: must be 1
+- #size-cells: must be 0
+- reg: BCM6328 LED controller address and size.
+
+Optional properties:
+- brcm,serial-leds: boolean which enables Serial LEDs.
+
+Each LED is represented as a sub-node of the brcm,bcm6328-leds device.
+
+LED sub-node required properties:
+- reg: LED pin number (only LEDs 0 to 23 are valid).
+
+Software controlled LED optional properties:
+- label (optional): see Documentation/devicetree/bindings/leds/common.txt
+- active-low (optional): boolean that makes LED active low.
+  Default: false
+- default-state (optional): see
+  Documentation/devicetree/bindings/leds/leds-gpio.txt
+- linux,default-trigger (optional): see
+  Documentation/devicetree/bindings/leds/common.txt
+
+Hardware controlled LED optional properties:
+- brcm,hardware-controlled: boolean that makes this LED hardware
+  controlled.
+- brcm,link-signal-sources: An array of hardware link
+  signal sources. Up to four link hardware signals can get muxed into
+  these LEDs. Only valid for LEDs 0 to 7, where LED signals 0 to 3 may
+  be muxed to LEDs 0 to 3, and signals 4 to 7 may be muxed to LEDs
+  4 to 7. A signal can be muxed to more than one LED, and one LED can
+  have more than one source signal.
+- brcm,activity-signal-sources: An array of hardware activity
+  signal sources. Up to four activity hardware signals can get muxed into
+  these LEDs. Only valid for LEDs 0 to 7, where LED signals 0 to 3 may
+  be muxed to LEDs 0 to 3, and signals 4 to 7 may be muxed to LEDs
+  4 to 7. A signal can be muxed to more than one LED, and one LED can
+  have more than one source signal.
+
+example 1) BCM6328 with 4 EPHY LEDs
+
+leds0: led-controller@10000800 {
+	compatible = "brcm,bcm6328-leds";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x10000800 0x24>;
+
+	alarm_red@2 {
+		reg = <2>;
+		active-low;
+		label = "red:alarm";
+	};
+	inet_green@3 {
+		reg = <3>;
+		active-low;
+		label = "green:inet";
+	};
+	power_green@4 {
+		reg = <4>;
+		active-low;
+		label = "green:power";
+		default-state = "on";
+	};
+	ephy0_spd@17 {
+		reg = <17>;
+		brcm,hardware-controlled;
+	};
+	ephy1_spd@18 {
+		reg = <18>;
+		brcm,hardware-controlled;
+	};
+	ephy2_spd@19 {
+		reg = <19>;
+		brcm,hardware-controlled;
+	};
+	ephy3_spd@20 {
+		reg = <20>;
+		brcm,hardware-controlled;
+	};
+};
+
+example 2) BCM63268 with Serial/GPHY0 LEDs
+
+leds0: led-controller@10001900 {
+	compatible = "brcm,bcm6328-leds";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x10001900 0x24>;
+	brcm,serial-leds;
+
+	gphy0_spd0@0 {
+		reg = <0>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <0>;
+	};
+	gphy0_spd1@1 {
+		reg = <1>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <1>;
+	};
+	inet_red@2 {
+		reg = <2>;
+		active-low;
+		label = "red:inet";
+	};
+	dsl_green@3 {
+		reg = <3>;
+		active-low;
+		label = "green:dsl";
+	};
+	usb_green@4 {
+		reg = <4>;
+		active-low;
+		label = "green:usb";
+	};
+	wps_green@7 {
+		reg = <7>;
+		active-low;
+		label = "green:wps";
+	};
+	inet_green@8 {
+		reg = <8>;
+		active-low;
+		label = "green:inet";
+	};
+	ephy0_act@9 {
+		reg = <9>;
+		brcm,hardware-controlled;
+	};
+	ephy1_act@10 {
+		reg = <10>;
+		brcm,hardware-controlled;
+	};
+	ephy2_act@11 {
+		reg = <11>;
+		brcm,hardware-controlled;
+	};
+	gphy0_act@12 {
+		reg = <12>;
+		brcm,hardware-controlled;
+	};
+	ephy0_spd@13 {
+		reg = <13>;
+		brcm,hardware-controlled;
+	};
+	ephy1_spd@14 {
+		reg = <14>;
+		brcm,hardware-controlled;
+	};
+	ephy2_spd@15 {
+		reg = <15>;
+		brcm,hardware-controlled;
+	};
+	power_green@20 {
+		reg = <20>;
+		active-low;
+		label = "green:power";
+		default-state = "on";
+	};
+};
+
+example 3) BCM6362 with 1 LED for each EPHY
+
+leds0: led-controller@10001900 {
+	compatible = "brcm,bcm6328-leds";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x10001900 0x24>;
+
+	usb@0 {
+		reg = <0>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <0>;
+		brcm,activity-signal-sources = <0>;
+		/* USB link/activity routed to USB LED */
+	};
+	inet@1 {
+		reg = <1>;
+		brcm,hardware-controlled;
+		brcm,activity-signal-sources = <1>;
+		/* INET activity routed to INET LED */
+	};
+	ephy0@4 {
+		reg = <4>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <4>;
+		/* EPHY0 link routed to EPHY0 LED */
+	};
+	ephy1@5 {
+		reg = <5>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <5>;
+		/* EPHY1 link routed to EPHY1 LED */
+	};
+	ephy2@6 {
+		reg = <6>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <6>;
+		/* EPHY2 link routed to EPHY2 LED */
+	};
+	ephy3@7 {
+		reg = <7>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <7>;
+		/* EPHY3 link routed to EPHY3 LED */
+	};
+	power_green@20 {
+		reg = <20>;
+		active-low;
+		label = "green:power";
+		default-state = "on";
+	};
+};
+
+example 4) BCM6362 with 1 LED for all EPHYs
+
+leds0: led-controller@10001900 {
+	compatible = "brcm,bcm6328-leds";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x10001900 0x24>;
+
+	usb@0 {
+		reg = <0>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <0 1>;
+		brcm,activity-signal-sources = <0 1>;
+		/* USB/INET link/activity routed to USB LED */
+	};
+	ephy@4 {
+		reg = <4>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <4 5 6 7>;
+		/* EPHY0/1/2/3 link routed to EPHY0 LED */
+	};
+	power_green@20 {
+		reg = <20>;
+		active-low;
+		label = "green:power";
+		default-state = "on";
+	};
+};
+
+example 5) BCM6362 with EPHY LEDs swapped
+
+leds0: led-controller@10001900 {
+	compatible = "brcm,bcm6328-leds";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	reg = <0x10001900 0x24>;
+
+	usb@0 {
+		reg = <0>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <0>;
+		brcm,activity-signal-sources = <0 1>;
+		/* USB link/activity & INET activity routed to USB LED */
+	};
+	ephy0@4 {
+		reg = <4>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <7>;
+		/* EPHY3 link routed to EPHY0 LED */
+	};
+	ephy1@5 {
+		reg = <5>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <6>;
+		/* EPHY2 link routed to EPHY1 LED */
+	};
+	ephy2@6 {
+		reg = <6>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <5>;
+		/* EPHY1 link routed to EPHY2 LED */
+	};
+	ephy3@7 {
+		reg = <7>;
+		brcm,hardware-controlled;
+		brcm,link-signal-sources = <4>;
+		/* EPHY0 link routed to EPHY3 LED */
+	};
+	power_green@20 {
+		reg = <20>;
+		active-low;
+		label = "green:power";
+		default-state = "on";
+	};
+};
-- 
1.9.1