--- /dev/null
+* Freescale MXS Pin Controller
+
+The pins controlled by mxs pin controller are organized in banks, each bank
+has 32 pins. Each pin has 4 multiplexing functions, and generally, the 4th
+function is GPIO. The configuration on the pins includes drive strength,
+voltage and pull-up.
+
+Required properties:
+- compatible: "fsl,imx23-pinctrl" or "fsl,imx28-pinctrl"
+- reg: Should contain the register physical address and length for the
+ pin controller.
+
+Please refer to pinctrl-bindings.txt in this directory for details of the
+common pinctrl bindings used by client devices.
+
+The node of mxs pin controller acts as a container for an arbitrary number of
+subnodes. Each of these subnodes represents some desired configuration for
+a group of pins, and only affects those parameters that are explicitly listed.
+In other words, a subnode that describes a drive strength parameter implies no
+information about pull-up. 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.
+
+Those subnodes under mxs pin controller node will fall into two categories.
+One is to set up a group of pins for a function, both mux selection and pin
+configurations, and it's called group node in the binding document. The other
+one is to adjust the pin configuration for some particular pins that need a
+different configuration than what is defined in group node. The binding
+document calls this type of node config node.
+
+On mxs, there is no hardware pin group. The pin group in this binding only
+means a group of pins put together for particular peripheral to work in
+particular function, like SSP0 functioning as mmc0-8bit. That said, the
+group node should include all the pins needed for one function rather than
+having these pins defined in several group nodes. It also means each of
+"pinctrl-*" phandle in client device node should only have one group node
+pointed in there, while the phandle can have multiple config node referenced
+there to adjust configurations for some pins in the group.
+
+Required subnode-properties:
+- fsl,pinmux-ids: An integer array. Each integer in the array specify a pin
+ with given mux function, with bank, pin and mux packed as below.
+
+ [15..12] : bank number
+ [11..4] : pin number
+ [3..0] : mux selection
+
+ This integer with mux selection packed is used as an entity by both group
+ and config nodes to identify a pin. The mux selection in the integer takes
+ effects only on group node, and will get ignored by driver with config node,
+ since config node is only meant to set up pin configurations.
+
+ Valid values for these integers are listed below.
+
+- reg: Should be the index of the group nodes for same function. This property
+ is required only for group nodes, and should not be present in any config
+ nodes.
+
+Optional subnode-properties:
+- fsl,drive-strength: Integer.
+ 0: MXS_DRIVE_4mA
+ 1: MXS_DRIVE_8mA
+ 2: MXS_DRIVE_12mA
+ 3: MXS_DRIVE_16mA
+- fsl,voltage: Integer.
+ 0: MXS_VOLTAGE_LOW - 1.8 V
+ 1: MXS_VOLTAGE_HIGH - 3.3 V
+- fsl,pull-up: Integer.
+ 0: MXS_PULL_DISABLE - Disable the internal pull-up
+ 1: MXS_PULL_ENABLE - Enable the internal pull-up
+
+Note that when enabling the pull-up, the internal pad keeper gets disabled.
+Also, some pins doesn't have a pull up, in that case, setting the fsl,pull-up
+will only disable the internal pad keeper.
+
+Examples:
+
+pinctrl@80018000 {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ compatible = "fsl,imx28-pinctrl";
+ reg = <0x80018000 2000>;
+
+ mmc0_8bit_pins_a: mmc0-8bit@0 {
+ reg = <0>;
+ fsl,pinmux-ids = <
+ MX28_PAD_SSP0_DATA0__SSP0_D0
+ MX28_PAD_SSP0_DATA1__SSP0_D1
+ MX28_PAD_SSP0_DATA2__SSP0_D2
+ MX28_PAD_SSP0_DATA3__SSP0_D3
+ MX28_PAD_SSP0_DATA4__SSP0_D4
+ MX28_PAD_SSP0_DATA5__SSP0_D5
+ MX28_PAD_SSP0_DATA6__SSP0_D6
+ MX28_PAD_SSP0_DATA7__SSP0_D7
+ MX28_PAD_SSP0_CMD__SSP0_CMD
+ MX28_PAD_SSP0_DETECT__SSP0_CARD_DETECT
+ MX28_PAD_SSP0_SCK__SSP0_SCK
+ >;
+ fsl,drive-strength = <MXS_DRIVE_4mA>;
+ fsl,voltage = <MXS_VOLTAGE_HIGH>;
+ fsl,pull-up = <MXS_PULL_ENABLE>;
+ };
+
+ mmc_cd_cfg: mmc-cd-cfg {
+ fsl,pinmux-ids = <MX28_PAD_SSP0_DETECT__SSP0_CARD_DETECT>;
+ fsl,pull-up = <MXS_PULL_DISABLE>;
+ };
+
+ mmc_sck_cfg: mmc-sck-cfg {
+ fsl,pinmux-ids = <MX28_PAD_SSP0_SCK__SSP0_SCK>;
+ fsl,drive-strength = <MXS_DRIVE_12mA>;
+ fsl,pull-up = <MXS_PULL_DISABLE>;
+ };
+};
+
+In this example, group node mmc0-8bit defines a group of pins for mxs SSP0
+to function as a 8-bit mmc device, with 8mA, 3.3V and pull-up configurations
+applied on all these pins. And config nodes mmc-cd-cfg and mmc-sck-cfg are
+adjusting the configuration for pins card-detection and clock from what group
+node mmc0-8bit defines. Only the configuration properties to be adjusted need
+to be listed in the config nodes.
+
+Valid values for i.MX28/i.MX23 pinmux-id are defined in
+arch/arm/boot/dts/imx28-pinfunc.h and arch/arm/boot/dts/imx23-pinfunc.h.
+The definitions for the padconfig properties can be found in
+arch/arm/boot/dts/mxs-pinfunc.h.
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