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| -rw-r--r-- | Documentation/devicetree/bindings/pinctrl/cnxt,cx92755-pinctrl.txt | 86 |
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diff --git a/Documentation/devicetree/bindings/pinctrl/cnxt,cx92755-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/cnxt,cx92755-pinctrl.txt new file mode 100644 index 000000000000..23ce8dc26990 --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/cnxt,cx92755-pinctrl.txt @@ -0,0 +1,86 @@ +Conexant Digicolor CX92755 General Purpose Pin Mapping + +This document describes the device tree binding of the pin mapping hardware +modules in the Conexant Digicolor CX92755 SoCs. The CX92755 in one of the +Digicolor series of SoCs. + +=== Pin Controller Node === + +Required Properties: + +- compatible: Must be "cnxt,cx92755-pinctrl" +- reg: Base address of the General Purpose Pin Mapping register block and the + size of the block. +- gpio-controller: Marks the device node as a GPIO controller. +- #gpio-cells: Must be <2>. The first cell is the pin number and the + second cell is used to specify flags. See include/dt-bindings/gpio/gpio.h + for possible values. + +For example, the following is the bare minimum node: + + pinctrl: pinctrl@f0000e20 { + compatible = "cnxt,cx92755-pinctrl"; + reg = <0xf0000e20 0x100>; + gpio-controller; + #gpio-cells = <2>; + }; + +As a pin controller device, in addition to the required properties, this node +should also contain the pin configuration nodes that client devices reference, +if any. + +For a general description of GPIO bindings, please refer to ../gpio/gpio.txt. + +=== Pin Configuration Node === + +Each pin configuration node is a sub-node of the pin controller node and is a +container of an arbitrary number of subnodes, called pin group nodes in this +document. + +Please refer to the pinctrl-bindings.txt in this directory for details of the +common pinctrl bindings used by client devices, including the definition of a +"pin configuration node". + +=== Pin Group Node === + +A pin group node specifies the desired pin mux for an arbitrary number of +pins. The name of the pin group node is optional and not used. + +A pin group node only affects the properties specified in the node, and has no +effect on any properties that are omitted. + +The pin group node accepts a subset of the generic pin config properties. For +details generic pin config properties, please refer to pinctrl-bindings.txt +and <include/linux/pinctrl/pinconfig-generic.h>. + +Required Pin Group Node Properties: + +- pins: Multiple strings. Specifies the name(s) of one or more pins to be + configured by this node. The format of a pin name string is "GP_xy", where x + is an uppercase character from 'A' to 'R', and y is a digit from 0 to 7. +- function: String. Specifies the pin mux selection. Values must be one of: + "gpio", "client_a", "client_b", "client_c" + +Example: + pinctrl: pinctrl@f0000e20 { + compatible = "cnxt,cx92755-pinctrl"; + reg = <0xf0000e20 0x100>; + + uart0_default: uart0_active { + data_signals { + pins = "GP_O0", "GP_O1"; + function = "client_b"; + }; + }; + }; + + uart0: uart@f0000740 { + compatible = "cnxt,cx92755-usart"; + ... + pinctrl-0 = <&uart0_default>; + pinctrl-names = "default"; + }; + +In the example above, a single pin group configuration node defines the +"client select" for the Rx and Tx signals of uart0. The uart0 node references +that pin configuration node using the &uart0_default phandle. |