Qualcomm Technologies, Inc. SLPI Pin controller

This DT bindings describes the Pin controller driver
being added for supporting SLPI (Sensor Low Power Island) TLMM
from QTI chipsets.

Following properties are for SLPI Pin controller device main node.
- compatible:
	Usage: required
	Value type: <string>
	Definition: must be "qcom,slpi-pinctrl"

- reg:
	Usage: required
	Value type: <prop-encoded-array>
	Definition: Base address and size of the SLPI TLMM register space.

- qcom,num-pins:
	Usage: required
	Value type: <u32>
	Definition: Number of PINs supported by the SLPI TLMM.

- clock-names:
	Usage: required
	value type: <string>
	Definition: Should be "ssc-clk"

- clocks:
	Usage: required
	value type: Phandle to ssc clk device node
	Definition: Handles to clocks specified in "clock-names" property.

Please refer to pinctrl-bindings.txt in this directory for details of the
common pinctrl bindings used by client devices, including the meaning of the
phrase "pin configuration node".

The pin configuration nodes act as a container for an arbitrary number of
subnodes. Each of these subnodes represents some desired configuration for a
pin or a list of pins. This configuration can include the
mux function to select on those pin(s), and various pin configuration
parameters, as listed below.

SUBNODES:

The name of each subnode is not important; all subnodes should be enumerated
and processed purely based on their content.

Each subnode only affects those parameters that are explicitly listed. In
other words, a subnode that lists a mux function but no pin configuration
parameters implies no information about any pin configuration parameters.
Similarly, a pin subnode that describes a pullup parameter implies no
information about e.g. the mux function.

The following generic properties as defined in pinctrl-bindings.txt are valid
to specify in a pin configuration subnode:

- pins:
	Usage: required
	Value type: <string-array>
	Definition: List of gpio pins affected by the properties specified in
		    this subnode.  Valid pins are: gpio0-gpio31 for LPI.

- function:
	Usage: required
	Value type: <string>
	Definition: Specify the alternative function to be configured for the
		    specified pins. Valid values are:
			"gpio",
			"func1",
			"func2",
			"func3",
			"func4",
			"func5"

- bias-disable:
	Usage: optional
	Value type: <none>
	Definition: The specified pins should be configured as no pull.

- bias-pull-down:
	Usage: optional
	Value type: <none>
	Definition: The specified pins should be configured as pull down.

- bias-bus-hold:
	Usage: optional
	Value type: <none>
	Definition: The specified pins should be configured as bus-keeper mode.

- bias-pull-up:
	Usage: optional
	Value type: <empty>
	Definition: The specified pins should be configured as pull up.

- qcom,drive-strength:
	Usage: optional
	Value type: <u32>
	Definition: Selects the drive strength for the specified pins.

Example:

	slpi_tlmm: slpi_pinctrl@2b40000 {
		compatible = "qcom,slpi-pinctrl";
		qcom,num-pins = <14>;
		clock-names = "ssc-clk";
		clocks =  <&clock_scc SCC_QUPV3_S_HCLK_CLK>;
		reg = <0x02b40000 0x20000>;

		slpi_mclk0_active: slpi_mclk0_active {
			mux {
				pins = "gpio0", "gpio1", "gpio2", "gpio3";
				function = "func2";
			};

			config {
				pins = "gpio0", "gpio1", "gpio2", "gpio3";
				drive-strength = <8>;
				bias-disable;
			};
		};

		slpi_mclk0_sleep: slpi_mclk0_sleep {
			mux {
				pins = "gpio0", "gpio1", "gpio2", "gpio3";
				function = "func2";
			};

			config {
				pins = "gpio0", "gpio1", "gpio2", "gpio3";
				drive-strength = <2>;
				bias-pull-down;
			};
		};

	};
