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atmel,sam-pinctrl

Vendor: Atmel Corporation

Description

Atmel SAM Pinctrl container node

The Atmel SAM pin controller is a singleton node responsible for controlling
pin function selection and pin properties. For example, you can use this node
to route USART0 RX to pin PA10 and enable the pull-up resistor on the pin.

The node has the 'pinctrl' node label set in your SoC's devicetree, so you can
modify it like this:

  &pinctrl {
          /* your modifications go here */
  };

All device pin configurations should be placed in child nodes of the 'pinctrl'
node, as shown in this example:

  /** You can put this in places like a <board>-pinctrl.dtsi file in
    * your board directory, or a devicetree overlay in your application.
    */

  /** include pre-defined combinations for the SoC variant used by the board */
  #include <dt-bindings/pinctrl/sam4sXc-pinctrl.h>

  &pinctrl {
    /* configuration for the usart0 "default" state */
    usart0_default: usart0_default {
      /* group 1 */
      group1 {
        /* configure PA6 as USART0 TX and PA8 as USART0 CTS */
        pinmux = <PA6A_USART0_TXD0>, <PA8A_USART0_CTS0>;
      };
      /* group 2 */
      group2 {
        /* configure PA5 as USART0 RX and PA7 as USART0 RTS */
        pinmux = <PA5A_USART0_RXD0>, <PA7A_USART0_RTS0>;
        /* both PA5 and PA7 have pull-up enabled */
        bias-pull-up;
      };
    };
  };

The 'usart0_default' child node encodes the pin configurations for a
particular state of a device; in this case, the default (that is, active)
state.

As shown, pin configurations are organized in groups within each child node.
Each group can specify a list of pin function selections in the 'pinmux'
property.

A group can also specify shared pin properties common to all the specified
pins, such as the 'bias-pull-up' property in group 2. Here is a list of
supported standard pin properties:

- bias-pull-up: Enable pull-up resistor.
- bias-pull-down: Enable pull-down resistor.
- drive-open-drain: Open-drain drive mode.

To link pin configurations with a device, use a pinctrl-N property for some
number N, like this example you could place in your board's DTS file:

  #include "board-pinctrl.dtsi"

  &usart0 {
        pinctrl-0 = <&usart0_default>;
        pinctrl-names = "default";
  };

Properties

Top level properties

These property descriptions apply to “atmel,sam-pinctrl” nodes themselves. This page also describes child node properties in the following sections.

Properties not inherited from the base binding file.

(None)

Grandchild node properties

Name

Type

Details

pinmux

array

An array of pins sharing the same group properties. The pins should
be defined using pre-defined macros or, alternatively, using the
SAM_PINMUX utility macros depending on the pinmux model used by the
SoC series.

This property is required.

bias-pull-up

boolean

enable pull-up resistor

bias-pull-down

boolean

enable pull-down resistor

drive-open-drain

boolean

drive with open drain (hardware AND)