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

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)

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.