Qualcomm SMSM Point-to-Point (SMP2P) GPIO Driver

Used to map an SMP2P entry and remote processor ID to a virtual GPIO controller
and virtual interrupt controller.

Required properties:
-compatible : should be "qcom,smp2pgpio";
-qcom,entry-name : name of the SMP2P entry
-qcom,remote-pid : the SMP2P remote processor ID (see smp2p_private_api.h)
-gpio-controller : specifies that this is a GPIO controller
-#gpio-cells : number of GPIO cells (should always be <2>)
-interrupt-controller : specifies that this is an interrupt controller
-#interrupt-cells : number of interrupt cells (should always be <2>)

Optional properties:
-qcom,is-inbound : specifies that this is an inbound entry (default is outbound)

Comments:
All device tree entries must be unique.  Therefore to prevent naming collisions
between clients, it is recommended that the DT nodes should be named using the
format:
	smp2pgpio_<ENTRY_NAME>_<REMOTE PID>_<in|out>

Unit test devices ("smp2p" entries):
-compatible : should be one of
		"qcom,smp2pgpio_test_smp2p_1_out"
		"qcom,smp2pgpio_test_smp2p_1_in"
		"qcom,smp2pgpio_test_smp2p_2_out"
		"qcom,smp2pgpio_test_smp2p_2_in"
		"qcom,smp2pgpio_test_smp2p_3_out"
		"qcom,smp2pgpio_test_smp2p_3_in"
		"qcom,smp2pgpio_test_smp2p_4_out"
		"qcom,smp2pgpio_test_smp2p_4_in"
		"qcom,smp2pgpio_test_smp2p_7_out"
		"qcom,smp2pgpio_test_smp2p_7_in"
		"qcom,smp2pgpio_test_smp2p_15_out"
		"qcom,smp2pgpio_test_smp2p_15_in"
-gpios : the relevant gpio pins of the entry

Example:
	/* Maps inbound "smp2p" entry on remote PID 7 to GPIO controller. */
	smp2pgpio_smp2p_7_in: qcom,smp2pgpio-smp2p-7-in {
		compatible = "qcom,smp2pgpio";
		qcom,entry-name = "smp2p";
		qcom,remote-pid = <7>;
		qcom,is-inbound;
		gpio-controller;
		#gpio-cells = <2>;
		interrupt-controller;
		#interrupt-cells = <2>;
	};

	/*
	 * Maps inbound "smp2p" entry on remote PID 7 to client driver
	 * "qcom,smp2pgpio_test_smp2p_7_in".
	 *
	 * Note:  If all 32-pins are used by this client, then you
	 *        can just list pin 0 here as a shortcut.
	 */
	qcom,smp2pgpio_test_smp2p_7_in {
		compatible = "qcom,smp2pgpio_test_smp2p_7_in";
		gpios = <&smp2pgpio_smp2p_7_in 0 0>, /* pin 0 */
			<&smp2pgpio_smp2p_7_in 1 0>,
			. . .
			<&smp2pgpio_smp2p_7_in 31 0>;    /* pin 31 */
	};


	/* Maps outbound "smp2p" entry on remote PID 7 to GPIO controller. */
	smp2pgpio_smp2p_7_out: qcom,smp2pgpio-smp2p-7-out {
		compatible = "qcom,smp2pgpio";
		qcom,entry-name = "smp2p";
		qcom,remote-pid = <7>;
		gpio-controller;
		#gpio-cells = <2>;
		interrupt-controller;
		#interrupt-cells = <2>;
	};

	/*
	 * Maps outbound "smp2p" entry on remote PID 7 to client driver
	 * "qcom,smp2pgpio_test_smp2p_7_out".
	 *
	 * Note:  If all 32-pins are used by this client, then you
	 *        can just list pin 0 here as a shortcut.
	 */
	qcom,smp2pgpio_test_smp2p_7_out {
		compatible = "qcom,smp2pgpio_test_smp2p_7_out";
		gpios = <&smp2pgpio_smp2p_7_out 0 0>, /* pin 0 */
			<&smp2pgpio_smp2p_7_out 1 0>,
			. . .
			<&smp2pgpio_smp2p_7_out 31 0>;    /* pin 31 */
	};