Bluetooth: btusb: Add out-of-band wakeup support

Some onboard BT chips (e.g. Marvell 8997) contain a wakeup pin that
can be connected to a gpio on the CPU side, and can be used to wakeup
the host out-of-band. This can be useful in situations where the
in-band wakeup is not possible or not preferable (e.g. the in-band
wakeup may require the USB host controller to remain active, and
hence consuming more system power during system sleep).

The oob gpio interrupt to be used for wakeup on the CPU side, is
read from the device tree node, (using standard interrupt descriptors).
A devcie tree binding document is also added for the driver. The
compatible string is in compliance with
Documentation/devicetree/bindings/usb/usb-device.txt

Signed-off-by: Rajat Jain <rajatja@google.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/net/btusb.txt b/Documentation/devicetree/bindings/net/btusb.txt
new file mode 100644
index 000000000000..2c0355c85972
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/btusb.txt
@@ -0,0 +1,40 @@
+Generic Bluetooth controller over USB (btusb driver)
+---------------------------------------------------
+
+Required properties:
+
+  - compatible : should comply with the format "usbVID,PID" specified in
+		 Documentation/devicetree/bindings/usb/usb-device.txt
+		 At the time of writing, the only OF supported devices
+		 (more may be added later) are:
+
+		  "usb1286,204e" (Marvell 8997)
+
+Optional properties:
+
+  - interrupt-parent: phandle of the parent interrupt controller
+  - interrupt-names: (see below)
+  - interrupts : The interrupt specified by the name "wakeup" is the interrupt
+		 that shall be used for out-of-band wake-on-bt. Driver will
+		 request this interrupt for wakeup. During system suspend, the
+		 irq will be enabled so that the bluetooth chip can wakeup host
+		 platform out of band. During system resume, the irq will be
+		 disabled to make sure unnecessary interrupt is not received.
+
+Example:
+
+Following example uses irq pin number 3 of gpio0 for out of band wake-on-bt:
+
+&usb_host1_ehci {
+    status = "okay";
+    #address-cells = <1>;
+    #size-cells = <0>;
+
+    mvl_bt1: bt@1 {
+	compatible = "usb1286,204e";
+	reg = <1>;
+	interrupt-parent = <&gpio0>;
+	interrupt-name = "wakeup";
+	interrupts = <3 IRQ_TYPE_LEVEL_LOW>;
+    };
+};