Documentation/devicetree/bindings/pinctrl/img,tz1090-pdc-pinctrl.txt

ImgTec TZ1090 PDC pin controller

Required properties:
- compatible: "img,tz1090-pdc-pinctrl"
- reg: Should contain the register physical address and length of the
  SOC_GPIO_CONTROL registers in the PDC register region.

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".

TZ1090-PDC's pin configuration nodes act as a container for an abitrary number
of subnodes. Each of these subnodes represents some desired configuration for a
pin, a group, or a list of pins or groups. This configuration can include the
mux function to select on those pin(s)/group(s), and various pin configuration
parameters, such as pull-up, drive strength, etc.

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. For this reason, even seemingly boolean
values are actually tristates in this binding: unspecified, off, or on.
Unspecified is represented as an absent property, and off/on are represented as
integer values 0 and 1.

Required subnode-properties:
- pins : An array of strings. Each string contains the name of a pin or group.
    Valid values for these names are listed below.

Optional subnode-properties:
- function: A string containing the name of the function to mux to the pin or
  group. Valid values for function names are listed below, including which
  pingroups can be muxed to them.
- tristate: Flag, put pin into high impedance state.
- pull-up: Flag, pull pin high.
- pull-down: Flag: pull pin low.
- bus-hold: Flag, weak latch last value on tristate bus.
- schmitt: Integer, enable or disable Schmitt trigger mode for the pins.
    0: no hysteresis
    1: schmitt trigger
- slew-rate: Integer, control slew rate of pins.
    0: slow (half frequency)
    1: fast
- drive-strength: Integer, control drive strength of pins in mA.
    2:  2mA
    4:  4mA
    8:  8mA
    12: 12mA
- power-on-start: Integer, power on start value of pins
    0: weak pull-down disabled
    1: weak pull-down for invalid power

Note that many of these properties are only valid for certain specific pins
or groups. See the TZ1090 TRM for complete details regarding which groups
support which functionality. The Linux pinctrl driver may also be a useful
reference.

Valid values for pin and group names are:

  pins:

    These all support tristate, pull-up, pull-down, and bus-hold (which can also
    be provided to any of the groups below to set it for all gpio pins in that
    group).

    gpio0, gpio1, sys_wake0, sys_wake1, sys_wake2, ir_data, ext_power.

  mux groups:

    These all support function.

    gpio0
        pins:       gpio0.
        function:   ir_mod_stable_out.
    gpio1
        pins:       gpio1.
        function:   ir_mod_power_out.

  drive groups:

    These support schmitt, slew-rate, drive-strength, and power-on-start.

    pdc
        pins:   gpio0, gpio1, sys_wake0, sys_wake1, sys_wake2, ir_data,
                ext_power.

Example:

	pinctrl_pdc: pinctrl@02006500 {
		#gpio-range-cells = <2>;
		compatible = "img,tz1090-pdc-pinctrl";
		reg = <0x02006500 0x100>;
	};

Example board file extracts:

	&pinctrl_pdc {
		pinctrl-names = "default";
		pinctrl-0 = <&syswake_default>;

		syswake_default: syswakes {
			syswake_cfg {
				pins =	"sys_wake0",
					"sys_wake1",
					"sys_wake2";
				pull-up;
			};
		};
		irmod_default: irmod {
			gpio0_cfg {
				pins =	"gpio0";
				function = "ir_mod_stable_out";
			};
			gpio1_cfg {
				pins =	"gpio1";
				function = "ir_mod_power_out";
			};
		};
	};

	ir: ir@02006200 {
		pinctrl-names = "default";
		pinctrl-0 = <&irmod_default>;
	};