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"

		    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

- qcom,gpios-disallowed:
	Usage: optional
	Value type: <prop-encoded-array>
	Definition: Array of the GPIO hardware numbers corresponding to GPIOs
		    which the APSS processor is not allowed to configure.
		    The hardware numbers are indexed from 1.
		    The interrupt resources for these GPIOs must not be defined
		    in "interrupts" and "interrupt-names" properties.
		    GPIOs defined in this array won't be registered as pins
		    in the pinctrl device or gpios in the gpio chip.

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

- 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",
			"analog"

- 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,atest:
	Usage: optional
	Value type: <u32>
	Definition: Selects ATEST rail to route to GPIO when it's configured
		    in analog-pass-through mode by specifying "analog" function.
		    Valid values are 0-3 corresponding to PMIC_GPIO_AOUT_ATESTx
		    defined in <dt-bindings/pinctrl/qcom,pmic-gpio.h>.

- qcom,dtest-buffer:
	Usage: optional
	Value type: <u32>
	Definition: Selects DTEST rail to route to GPIO when it's configured
		    as a digital input.
		    For LV/MV GPIO subtypes, the valid values are 0-3
		    corresponding to PMIC_GPIO_DIN_DTESTx defined in
		    <dt-bindings/pinctrl/qcom,pmic-gpio.h>. Only one
		    DTEST rail can be selected at a time.
		    For 4CH/8CH GPIO subtypes, supported values are 1-15.
		    4 DTEST rails are supported in total and more than 1 DTEST
		    rail can be selected simultaneously. Each bit of the
		    4 LSBs represent one DTEST rail, such as [3:0] = 0101
		    means both DTEST1 and DTEST3 are selected.

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>;
		qcom,gpios-disallowed = <1 20>;

		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>;
			};
		};
	};