nordic,nrf-pinctrl

Vendor: Nordic Semiconductor

Description

The nRF pin controller is a singleton node responsible for controlling
pin function selection and pin properties. For example, you can use this
node to route UART0 RX to pin P0.1 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.
   */
  &pinctrl {
    /* configuration for uart0 device, default state */
    uart0_default: uart0_default {
      /* group 1 ('group1' name is arbitrary) */
      group1 {
        /* configure P0.1 as UART_TX and P0.2 as UART_RTS */
        psels = <NRF_PSEL(UART_TX, 0, 1)>, <NRF_PSEL(UART_RTS, 0, 2)>;
      };
      /* group 2 */
      group2 {
        /* configure P0.3 as UART_RX and P0.4 as UART_CTS */
        psels = <NRF_PSEL(UART_RX, 0, 3)>, <NRF_PSEL(UART_CTS, 0, 4)>;
        /* both P0.3 and P0.4 are configured with pull-up */
        bias-pull-up;
      };
    };
  };

The 'uart0_default' child node encodes the pin configurations for a
particular state of a device; in this case, the default (that is, active)
state. You would specify the low-power configuration for the same device
in a separate child node.

As shown, pin configurations are organized in groups within each child node.
Each group can specify a list of pin function selections in the 'psels'
property. The NRF_PSEL macro is used to specify a pin function selection.
If a pin needs to be explicitly disconnected, there is also the
NRF_PSEL_DISCONNECTED macro.
Available pin functions can be found in the
include/zephyr/dt-bindings/pinctrl/nrf-pinctrl.h header file.

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-disable: Disable pull-up/down (default behavior, not required).
- bias-pull-up: Enable pull-up resistor.
- bias-pull-down: Enable pull-down resistor.
- low-power-enable: Configure pin as an input with input buffer
  disconnected.

Note that bias options are mutually exclusive.

To link this pin configuration 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"

   &uart0 {
         pinctrl-0 = <&uart0_default>;
         pinctrl-names = "default";
   };

Properties

Top level properties

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

Node specific propertiesDeprecated node specific propertiesBase properties

Properties not inherited from the base binding file.

(None)

Grandchild node properties

Name	Type	Details
psels	array	An array of pins sharing the same group properties. The pins should be defined using the NRF_PSEL utility macro that encodes the port, pin and function. NRF_PSEL_DISCONNECTED is also available to explicitly disconnect a pin. This property is required.
nordic,drive-mode	int	Pin output drive mode. Available drive modes are pre-defined in nrf-pinctrl.h. Note that extra modes may not be available on certain devices. Defaults to standard mode for 0 and 1 (NRF_DRIVE_S0S1), the SoC default, except for the "nordic,nrf-twi" and "nordic,nrf-twim" nodes where NRF_DRIVE_S0S1 is always overridden with NRF_DRIVE_S0D1 (standard '0', disconnect '1').
nordic,invert	boolean	Invert pin polarity (set the active state to low). Only valid for PWM channel output pins.
bias-disable	boolean	disable any pin bias
bias-pull-up	boolean	enable pull-up resistor
bias-pull-down	boolean	enable pull-down resistor
low-power-enable	boolean	enable low power mode