Add pinctrl device tree binding documentation for the General Purpose Pin
Mapping module of the Conexant CX92755 SoC.
Signed-off-by: Baruch Siach <baruch@xxxxxxxxxx>
---
.../bindings/pinctrl/cnxt,cx92755-pinctrl.txt | 86 ++++++++++++++++++++++
1 file changed, 86 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pinctrl/cnxt,cx92755-pinctrl.txt
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.
--
2.1.4
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