Qualcomm PMIC GPIO block

This binding describes the GPIO block(s) found in the 8xxx series of
PMIC's from Qualcomm.

- compatible:
	Usage: required
	Value type: <string>
	Definition: must be one of:
		    "qcom,pm8018-gpio"
		    "qcom,pm8038-gpio"
		    "qcom,pm8058-gpio"
		    "qcom,pm8916-gpio"
		    "qcom,pm8917-gpio"
		    "qcom,pm8921-gpio"
		    "qcom,pm8941-gpio"
		    "qcom,pm8994-gpio"
		    "qcom,pma8084-gpio"
		    "qcom,pmi8994-gpio"

		    And must contain either "qcom,spmi-gpio" or "qcom,ssbi-gpio"
		    if the device is on an spmi bus or an ssbi bus respectively

- reg:
	Usage: required
	Value type: <prop-encoded-array>
	Definition: Register base of the GPIO block and length.

- interrupts:
	Usage: required
	Value type: <prop-encoded-array>
	Definition: Must contain an array of encoded interrupt specifiers for
		    each available GPIO

- gpio-controller:
	Usage: required
	Value type: <none>
	Definition: Mark the device node as a GPIO controller

- #gpio-cells:
	Usage: required
	Value type: <u32>
	Definition: Must be 2;
		    the first cell will be used to define gpio number and the
		    second denotes the flags for this gpio

Please refer to ../gpio/gpio.txt and ../interrupt-controller/interrupts.txt for
a general description of GPIO and interrupt bindings.

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:
		    gpio1-gpio6 for pm8018
		    gpio1-gpio12 for pm8038
		    gpio1-gpio40 for pm8058
		    gpio1-gpio4 for pm8916
		    gpio1-gpio38 for pm8917
		    gpio1-gpio44 for pm8921
		    gpio1-gpio36 for pm8941
		    gpio1-gpio22 for pm8994
		    gpio1-gpio22 for pma8084
		    gpio1-gpio10 for pmi8994

- function:
	Usage: required
	Value type: <string>
	Definition: Specify the alternative function to be configured for the
		    specified pins.  Valid values are:
		    "normal",
		    "paired",
		    "func1",
		    "func2",
		    "dtest1",
		    "dtest2",
		    "dtest3",
		    "dtest4",
		    And following values are supported by LV/MV GPIO subtypes:
		    "func3",
		    "func4"

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

- qcom,pull-up-strength:
	Usage: optional
	Value type: <u32>
	Definition: Specifies the strength to use for pull up, if selected.
		    Valid values are; as defined in
		    <dt-bindings/pinctrl/qcom,pmic-gpio.h>:
		    1: 30uA                     (PMIC_GPIO_PULL_UP_30)
		    2: 1.5uA                    (PMIC_GPIO_PULL_UP_1P5)
		    3: 31.5uA                   (PMIC_GPIO_PULL_UP_31P5)
		    4: 1.5uA + 30uA boost       (PMIC_GPIO_PULL_UP_1P5_30)
		    If this property is omitted 30uA strength will be used if
		    pull up is selected

- bias-high-impedance:
	Usage: optional
	Value type: <none>
	Definition: The specified pins will put in high-Z mode and disabled.

- input-enable:
	Usage: optional
	Value type: <none>
	Definition: The specified pins are put in input mode.

- output-high:
	Usage: optional
	Value type: <none>
	Definition: The specified pins are configured in output mode, driven
		    high.

- output-low:
	Usage: optional
	Value type: <none>
	Definition: The specified pins are configured in output mode, driven
		    low.

- power-source:
	Usage: optional
	Value type: <u32>
	Definition: Selects the power source for the specified pins. Valid
		    power sources are defined per chip in
		    <dt-bindings/pinctrl/qcom,pmic-gpio.h>

- qcom,drive-strength:
	Usage: optional
	Value type: <u32>
	Definition: Selects the drive strength for the specified pins. Value
		    drive strengths are:
		    0: no (PMIC_GPIO_STRENGTH_NO)
		    1: high (PMIC_GPIO_STRENGTH_HIGH) 0.9mA @ 1.8V - 1.9mA @ 2.6V
		    2: medium (PMIC_GPIO_STRENGTH_MED) 0.6mA @ 1.8V - 1.25mA @ 2.6V
		    3: low (PMIC_GPIO_STRENGTH_LOW) 0.15mA @ 1.8V - 0.3mA @ 2.6V
		    as defined in <dt-bindings/pinctrl/qcom,pmic-gpio.h>

- drive-push-pull:
	Usage: optional
	Value type: <none>
	Definition: The specified pins are configured in push-pull mode.

- drive-open-drain:
	Usage: optional
	Value type: <none>
	Definition: The specified pins are configured in open-drain mode.

- drive-open-source:
	Usage: optional
	Value type: <none>
	Definition: The specified pins are configured in open-source mode.

- qcom,analog-pass:
	Usage: optional
	Value type: <none>
	Definition: The specified pins are configured in analog-pass-through mode.

- qcom,atest:
	Usage: optional
	Value type: <u32>
	Definition: Selects ATEST rail to route to GPIO when it's configured
		    in analog-pass-through mode.
		    Valid values are 1-4 corresponding to ATEST1 to ATEST4.

- qcom,dtest-buffer:
	Usage: optional
	Value type: <u32>
	Definition: Selects DTEST rail to route to GPIO when it's configured
		    as digital input.
		    Valid values are 1-4 corresponding to DTEST1 to DTEST4.

Example:

	pm8921_gpio: gpio@150 {
		compatible = "qcom,pm8921-gpio", "qcom,ssbi-gpio";
		reg = <0x150 0x160>;
		interrupts = <192 1>, <193 1>, <194 1>,
			     <195 1>, <196 1>, <197 1>,
			     <198 1>, <199 1>, <200 1>,
			     <201 1>, <202 1>, <203 1>,
			     <204 1>, <205 1>, <206 1>,
			     <207 1>, <208 1>, <209 1>,
			     <210 1>, <211 1>, <212 1>,
			     <213 1>, <214 1>, <215 1>,
			     <216 1>, <217 1>, <218 1>,
			     <219 1>, <220 1>, <221 1>,
			     <222 1>, <223 1>, <224 1>,
			     <225 1>, <226 1>, <227 1>,
			     <228 1>, <229 1>, <230 1>,
			     <231 1>, <232 1>, <233 1>,
			     <234 1>, <235 1>;

		gpio-controller;
		#gpio-cells = <2>;

		pm8921_gpio_keys: gpio-keys {
			volume-keys {
				pins = "gpio20", "gpio21";
				function = "normal";

				input-enable;
				bias-pull-up;
				drive-push-pull;
				qcom,drive-strength = <PMIC_GPIO_STRENGTH_NO>;
				power-source = <PM8921_GPIO_S4>;
			};
		};
	};