122 lines
4.3 KiB
YAML
122 lines
4.3 KiB
YAML
# Copyright (c) 2021 Nordic Semiconductor ASA
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# SPDX-License-Identifier: Apache-2.0
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description: |
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The nRF pin controller is a singleton node responsible for controlling
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pin function selection and pin properties. For example, you can use this
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node to route UART0 RX to pin P0.1 and enable the pull-up resistor on the
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pin.
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The node has the 'pinctrl' node label set in your SoC's devicetree,
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so you can modify it like this:
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&pinctrl {
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/* your modifications go here */
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};
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All device pin configurations should be placed in child nodes of the
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'pinctrl' node, as shown in this example:
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/* You can put this in places like a board-pinctrl.dtsi file in
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* your board directory, or a devicetree overlay in your application.
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*/
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&pinctrl {
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/* configuration for uart0 device, default state */
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uart0_default: uart0_default {
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/* group 1 ('group1' name is arbitrary) */
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group1 {
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/* configure P0.1 as UART_TX and P0.2 as UART_RTS */
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psels = <NRF_PSEL(UART_TX, 0, 1)>, <NRF_PSEL(UART_RTS, 0, 2)>;
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};
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/* group 2 */
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group2 {
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/* configure P0.3 as UART_RX and P0.4 as UART_CTS */
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psels = <NRF_PSEL(UART_RX, 0, 3)>, <NRF_PSEL(UART_CTS, 0, 4)>;
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/* both P0.3 and P0.4 are configured with pull-up */
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bias-pull-up;
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};
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};
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};
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The 'uart0_default' child node encodes the pin configurations for a
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particular state of a device; in this case, the default (that is, active)
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state. You would specify the low-power configuration for the same device
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in a separate child node.
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As shown, pin configurations are organized in groups within each child node.
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Each group can specify a list of pin function selections in the 'psels'
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property. The NRF_PSEL macro is used to specify a pin function selection.
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If a pin needs to be explicitly disconnected, there is also the
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NRF_PSEL_DISCONNECTED macro.
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Available pin functions can be found in the
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include/zephyr/dt-bindings/pinctrl/nrf-pinctrl.h header file.
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A group can also specify shared pin properties common to all the specified
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pins, such as the 'bias-pull-up' property in group 2. Here is a list of
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supported standard pin properties:
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- bias-disable: Disable pull-up/down (default behavior, not required).
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- bias-pull-up: Enable pull-up resistor.
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- bias-pull-down: Enable pull-down resistor.
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- low-power-enable: Configure pin as an input with input buffer
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disconnected.
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Note that bias options are mutually exclusive.
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To link this pin configuration with a device, use a pinctrl-N property
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for some number N, like this example you could place in your board's DTS
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file:
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#include "board-pinctrl.dtsi"
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&uart0 {
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pinctrl-0 = <&uart0_default>;
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pinctrl-names = "default";
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};
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compatible: "nordic,nrf-pinctrl"
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include: base.yaml
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child-binding:
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description: |
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nRF pin controller pin configuration state nodes.
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child-binding:
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description: |
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nRF pin controller pin configuration group.
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include:
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- name: pincfg-node.yaml
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property-allowlist:
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- bias-disable
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- bias-pull-down
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- bias-pull-up
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- low-power-enable
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properties:
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psels:
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required: true
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type: array
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description: |
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An array of pins sharing the same group properties. The pins should
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be defined using the NRF_PSEL utility macro that encodes the port,
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pin and function. NRF_PSEL_DISCONNECTED is also available to explicitly
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disconnect a pin.
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nordic,drive-mode:
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type: int
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default: 0
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description: |
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Pin output drive mode. Available drive modes are pre-defined in
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nrf-pinctrl.h. Note that extra modes may not be available on certain
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devices. Defaults to standard mode for 0 and 1 (NRF_DRIVE_S0S1), the
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SoC default, except for the "nordic,nrf-twi" and "nordic,nrf-twim"
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nodes where NRF_DRIVE_S0S1 is always overridden with NRF_DRIVE_S0D1
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(standard '0', disconnect '1').
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nordic,invert:
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type: boolean
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description: |
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Invert pin polarity (set the active state to low).
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Only valid for PWM channel output pins.
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