pinctrl: lochnagar: Add initial binding documentation

Lochnagar is an evaluation and development board for Cirrus
Logic Smart CODEC and Amp devices. It allows the connection of
most Cirrus Logic devices on mini-cards, as well as allowing
connection of various application processor systems to provide a
full evaluation platform. This driver supports the board
controller chip on the Lochnagar board.
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/cirrus,lochnagar.txt

+Cirrus Logic Lochnagar Audio Development Board
+
+Lochnagar is an evaluation and development board for Cirrus Logic
+Smart CODEC and Amp devices. It allows the connection of most Cirrus
+Logic devices on mini-cards, as well as allowing connection of
+various application processor systems to provide a full evaluation
+platform.  Audio system topology, clocking and power can all be
+controlled through the Lochnagar, allowing the device under test
+to be used in a variety of possible use cases.
+
+This binding document describes the binding for the pinctrl portion
+of the driver.
+
+Also see these documents for generic binding information:
+  [1] GPIO : ../gpio/gpio.txt
+  [2] Pinctrl: ../pinctrl/pinctrl-bindings.txt
+
+And these for relevant defines:
+  [3] include/dt-bindings/pinctrl/lochnagar.h
+
+This binding must be part of the Lochnagar MFD binding:
+  [4] ../mfd/cirrus,lochnagar.txt
+
+Required properties:
+
+  - compatible : One of the following strings:
+                 "cirrus,lochnagar-pinctrl"
+
+  - gpio-controller : Indicates this device is a GPIO controller.
+  - #gpio-cells : Must be 2. The first cell is the pin number, see
+    [3] for available pins and the second cell is used to specify
+    optional parameters, see [1].
+  - gpio-ranges : Range of pins managed by the GPIO controller, see
+    [1]. Both the GPIO and Pinctrl base should be set to zero and the
+    count to the appropriate of the LOCHNAGARx_PIN_NUM_GPIOS define,
+    see [3].
+
+  - pinctrl-names : A pinctrl state named "default" must be defined.
+  - pinctrl-0 : A phandle to the default pinctrl state.
+
+Required sub-nodes:
+
+The pin configurations are defined as a child of the pinctrl states
+node, see [2]. Each sub-node can have the following properties:
+  - groups : A list of groups to select (either this or "pins" must be
+    specified), available groups:
+      codec-aif1, codec-aif2, codec-aif3, dsp-aif1, dsp-aif2, psia1,
+      psia2, gf-aif1, gf-aif2, gf-aif3, gf-aif4, spdif-aif, usb-aif1,
+      usb-aif2, adat-aif, soundcard-aif
+  - pins : A list of pin names to select (either this or "groups" must
+    be specified), available pins:
+      fpga-gpio1, fpga-gpio2, fpga-gpio3, fpga-gpio4, fpga-gpio5,
+      fpga-gpio6, codec-gpio1, codec-gpio2, codec-gpio3, codec-gpio4,
+      codec-gpio5, codec-gpio6, codec-gpio7, codec-gpio8, dsp-gpio1,
+      dsp-gpio2, dsp-gpio3, dsp-gpio4, dsp-gpio5, dsp-gpio6, gf-gpio2,
+      gf-gpio3, gf-gpio7, codec-aif1-bclk, codec-aif1-rxdat,
+      codec-aif1-lrclk, codec-aif1-txdat, codec-aif2-bclk,
+      codec-aif2-rxdat, codec-aif2-lrclk, codec-aif2-txdat,
+      codec-aif3-bclk, codec-aif3-rxdat, codec-aif3-lrclk,
+      codec-aif3-txdat, dsp-aif1-bclk, dsp-aif1-rxdat, dsp-aif1-lrclk,
+      dsp-aif1-txdat, dsp-aif2-bclk, dsp-aif2-rxdat,
+      dsp-aif2-lrclk, dsp-aif2-txdat, psia1-bclk, psia1-rxdat,
+      psia1-lrclk, psia1-txdat, psia2-bclk, psia2-rxdat, psia2-lrclk,
+      psia2-txdat, gf-aif3-bclk, gf-aif3-rxdat, gf-aif3-lrclk,
+      gf-aif3-txdat, gf-aif4-bclk, gf-aif4-rxdat, gf-aif4-lrclk,
+      gf-aif4-txdat, gf-aif1-bclk, gf-aif1-rxdat, gf-aif1-lrclk,
+      gf-aif1-txdat, gf-aif2-bclk, gf-aif2-rxdat, gf-aif2-lrclk,
+      gf-aif2-txdat, dsp-uart1-rx, dsp-uart1-tx, dsp-uart2-rx,
+      dsp-uart2-tx, gf-uart2-rx, gf-uart2-tx, usb-uart-rx,
+      codec-pdmclk1, codec-pdmdat1, codec-pdmclk2, codec-pdmdat2,
+      codec-dmicclk1, codec-dmicdat1, codec-dmicclk2, codec-dmicdat2,
+      codec-dmicclk3, codec-dmicdat3, codec-dmicclk4, codec-dmicdat4,
+      dsp-dmicclk1, dsp-dmicdat1, dsp-dmicclk2, dsp-dmicdat2, i2c2-scl,
+      i2c2-sda, i2c3-scl, i2c3-sda, i2c4-scl, i2c4-sda, dsp-standby,
+      codec-mclk1, codec-mclk2, dsp-clkin, psia1-mclk, psia2-mclk,
+      gf-gpio1, gf-gpio5, dsp-gpio20, led1, led2
+  - function : The mux function to select, available functions:
+      aif, fpga-gpio1, fpga-gpio2, fpga-gpio3, fpga-gpio4, fpga-gpio5,
+      fpga-gpio6, codec-gpio1, codec-gpio2, codec-gpio3, codec-gpio4,
+      codec-gpio5, codec-gpio6, codec-gpio7, codec-gpio8, dsp-gpio1,
+      dsp-gpio2, dsp-gpio3, dsp-gpio4, dsp-gpio5, dsp-gpio6, gf-gpio2,
+      gf-gpio3, gf-gpio7, gf-gpio1, gf-gpio5, dsp-gpio20, codec-clkout,
+      dsp-clkout, pmic-32k, spdif-clkout, clk-12m288, clk-11m2986,
+      clk-24m576, clk-22m5792, xmos-mclk, gf-clkout1, gf-mclk1,
+      gf-mclk3, gf-mclk2, gf-clkout2, codec-mclk1, codec-mclk2,
+      dsp-clkin, psia1-mclk, psia2-mclk, spdif-mclk, codec-irq,
+      codec-reset, dsp-reset, dsp-irq, dsp-standby, codec-pdmclk1,
+      codec-pdmdat1, codec-pdmclk2, codec-pdmdat2, codec-dmicclk1,
+      codec-dmicdat1, codec-dmicclk2, codec-dmicdat2, codec-dmicclk3,
+      codec-dmicdat3, codec-dmicclk4, codec-dmicdat4, dsp-dmicclk1,
+      dsp-dmicdat1, dsp-dmicclk2, dsp-dmicdat2, dsp-uart1-rx,
+      dsp-uart1-tx, dsp-uart2-rx, dsp-uart2-tx, gf-uart2-rx,
+      gf-uart2-tx, usb-uart-rx, usb-uart-tx, i2c2-scl, i2c2-sda,
+      i2c3-scl, i2c3-sda, i2c4-scl, i2c4-sda, spdif-aif, psia1,
+      psia1-bclk, psia1-lrclk, psia1-rxdat, psia1-txdat, psia2,
+      psia2-bclk, psia2-lrclk, psia2-rxdat, psia2-txdat, codec-aif1,
+      codec-aif1-bclk, codec-aif1-lrclk, codec-aif1-rxdat,
+      codec-aif1-txdat, codec-aif2, codec-aif2-bclk, codec-aif2-lrclk,
+      codec-aif2-rxdat, codec-aif2-txdat, codec-aif3, codec-aif3-bclk,
+      codec-aif3-lrclk, codec-aif3-rxdat, codec-aif3-txdat, dsp-aif1,
+      dsp-aif1-bclk, dsp-aif1-lrclk, dsp-aif1-rxdat, dsp-aif1-txdat,
+      dsp-aif2, dsp-aif2-bclk, dsp-aif2-lrclk, dsp-aif2-rxdat,
+      dsp-aif2-txdat, gf-aif3, gf-aif3-bclk, gf-aif3-lrclk,
+      gf-aif3-rxdat, gf-aif3-txdat, gf-aif4, gf-aif4-bclk,
+      gf-aif4-lrclk, gf-aif4-rxdat, gf-aif4-txdat, gf-aif1,
+      gf-aif1-bclk, gf-aif1-lrclk, gf-aif1-rxdat, gf-aif1-txdat,
+      gf-aif2, gf-aif2-bclk, gf-aif2-lrclk, gf-aif2-rxdat,
+      gf-aif2-txdat, usb-aif1, usb-aif2, adat-aif, soundcard-aif,
+
+  - output-enable : Specifies that an AIF group will be used as a master
+    interface (either this or input-enable is required if a group is
+    being muxed to an AIF)
+  - input-enable : Specifies that an AIF group will be used as a slave
+    interface (either this or output-enable is required if a group is
+    being muxed to an AIF)
+
+Example:
+
+lochnagar-pinctrl {
+	compatible = "cirrus,lochnagar-pinctrl";
+
+	gpio-controller;
+	#gpio-cells = <2>;
+	gpio-ranges = <&lochnagar 0 0 LOCHNAGAR2_PIN_NUM_GPIOS>;
+
+	pinctrl-names = "default";
+	pinctrl-0 = <&pin-settings>;
+
+	pin-settings: pin-settings {
+		ap-aif {
+			input-enable;
+			groups = "gf-aif1";
+			function = "codec-aif3";
+		};
+		codec-aif {
+			output-enable;
+			groups = "codec-aif3";
+			function = "gf-aif1";
+		};
+	};
+};