* Bluetooth Controller
Bluetooth controller communicates with the Bluetooth Host using HCI Transport
layer. HCI Transport layer can be based on UART or USB serial communication
protocol.

Required properties:
	- compatible: Should be set to one of the following:
		qca,ar3002
		qca,qca6174
		qca,wcn3990
                qca,qca6390
		qca,wcn6750
	- qca,bt-reset-gpio: GPIO pin to bring BT Controller out of reset
	- qca,wl-reset-gpio: GPIO pin for WLAN EN, used here to check status only

Optional properties:
	- qca,bt-vdd-pa-supply: Bluetooth VDD PA regulator handle
	- qca,bt-vdd-io-supply: Bluetooth VDD IO regulator handle
	- qca,bt-vdd-ldo-supply: Bluetooth VDD LDO regulator handle. Kept under
		optional parameters as some of the chipsets doesn't require ldo
		or it may use from same vddio.
	- qca,bt-vdd-xtal-supply: Bluetooth VDD XTAL regulator handle
	- qca,bt-vdd-core-supply: Bluetooth VDD CORE regulator handle
	- qca,bt-vdd-asd-supply: Bluetooth VDD regulator handle for antenna switch
    diversity.
	- qca,bt-chip-pwd-supply: Chip power down gpio is required when bluetooth
		module and other modules like wifi co-exist in a singe chip and
		shares a common gpio to bring chip out of reset.
	- qca,bt-vdd-pa-voltage-level: specifies VDD PA voltage levels for supply.
		Should be specified in pairs (min, max), units uV
	- qca,bt-vdd-io-voltage-level: specifies VDD IO voltage levels for supply.
		Should be specified in pairs (min, max), units uV
	- qca,bt-vdd-ldo-voltage-level: specifies VDD LDO voltage levels for supply.
		Should be specified in pairs (min, max), units uV
	- qca,bt-vdd-xtal-voltage-level: specifies VDD XTAL voltage levels for supply.
		Should be specified in pairs (min, max), units uV
	- qca,bt-vdd-core-voltage-level: specifies VDD CORE voltage levels for supply.
	- qca,bt-vdd-asd-voltage-level: specifies VDD  voltage levels for supply for
    antenna switch diversity.  Should be specified in pairs (min, max), units uV
	- qca,bt-vdd-io-current-level: specifies VDD IO current level in microamps
	- qca,bt-vdd-xtal-current-level: specifies VDD XTAL current level in microamps
	- qca,bt-vdd-core-current-level: specifies VDD CORE current level in microamps.
	- qca,bt-vdd-ldo-current-level: specifies VDD LDO current level in microamps.
	- qca,bt-vdd-pa-current-level: specifies VDD PA current level in microamps.
	- qca,bt-chip-pwd-current-level: specifies Chip Power current level in microamps.
	- qca,bt-vdd-asd-current-level: specifies VDD  ASD current level

Example:
	bluetooth: bt_qca6390 {
		compatible = "qca,qca6390";
		pinctrl-names = "default";
		pinctrl-0 = <&bt_en_sleep>;
		qca,bt-reset-gpio = <&tlmm 21 0>; /* BT_EN */
		qca,wl-reset-gpio = <&tlmm 20 0>; /* WL_EN */
		qca,bt-vdd-aon-supply = <&pm8150_s6>;
		qca,bt-vdd-dig-supply = <&pm8009_s2>;
		qca,bt-vdd-rfa1-supply = <&pm8150_s5>;
		qca,bt-vdd-rfa2-supply = <&pm8150a_s8>;
		qca,bt-vdd-asd-supply = <&pm8150_l16>;

		qca,bt-vdd-aon-voltage-level = <950000 950000>;
		qca,bt-vdd-dig-voltage-level = <950000 952000>;
		qca,bt-vdd-rfa1-voltage-level = <1900000 1900000>;
		qca,bt-vdd-rfa2-voltage-level = <1350000 1350000>;
		qca,bt-vdd-asd-voltage-level = <3024000 3304000>;

		qca,bt-vdd-asd-current-level = <10000>;

		qca,bt-vdd-io-current-level = <1>; /* LPM/PFM */
		qca,bt-vdd-xtal-current-level = <1>; /* LPM/PFM */
		qca,bt-vdd-core-current-level = <1>; /* LPM/PFM */
		qca,bt-vdd-ldo-current-level = <1>; /* LPM/PFM */
		qca,bt-vdd-pa-current-level = <1>; /* LPM/PFM */
	};