nitrous.txt

* Nitrous Bluetooth Power Management Driver

The Nitrous BT power management is designed to handle the power management
between a host processor and a BT controller.  In its current form, the
driver is specific to the power management between a MSM processor and a
Broadcom BT controller over UART communication.

The driver handles the following key power management elements:
-rfkill.
-host-wake-gpio/dev-wake-gpio sleep protocol.
-serial driver power management.

On Tx, the driver registers and receives a callback from the serial core to
toggle the dev-wake-gpio and utilizes the PM Runtime framework to wake up
the serial driver for transmission.

On Rx, the driver listens to the host-wake GPIO and wakes up the serial driver
to receive incoming data.  The host-wake GPIO is also capable of waking up
the host processor from suspend.

Required Properties:
  - compatible: "goog,nitrous"
  - uart-port = UART port number for serial communication.
  - power-gpio = GPIO number for controller power.
  - host-wake-gpio: GPIO number for host wake signal (controller to host).
  - host-wake-polarity: Polarity for host wake GPIO
                        (0: active low; 1: active high).
  - dev-wake-gpio: GPIO number for controller wake signal (host to controller).
  - dev-wake-polarity: Polarity for dev wake GPIO
                       (0: active low; 1: active high).

Optional Properties:
  None

Example:
	bt_nitrous {
		compatible = "goog,nitrous";
		uart-port = <6>;
		power-gpio = <&msmgpio 10 0>;
		host-wake-gpio = <&msmgpio 20 0>;
		host-wake-polarity = <0>;
		dev-wake-gpio = <&msmgpio 30 0>;
		dev-wake-polarity = <0>;
	};