raspberrypi,pico-pinctrl
Vendor: Raspberry Pi Foundation
Description
The RPi Pico pin controller is a node responsible for controlling
pin function selection and pin properties, such as routing a UART0 Rx
to pin 1 and enabling the pullup resistor on that 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/rpi-pico-rp2040-pinctrl.h>
&pinctrl {
/* configuration for the usart0 "default" state */
uart0_default: uart0_default {
/* group 1 */
group1 {
/* configure P0 as UART0 TX */
pinmux = <UART0_TX_P0>;
};
/* group 2 */
group2 {
/* configure P1 as UART0 RX */
pinmux = <UART0_RX_P1>;
/* enable input on pin 1 */
input-enable;
};
};
};
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.
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 'input-enable' property in group 2. Here is a list of
supported standard pin properties:
- bias-disable: Disable pull-up/down (default, not required).
- bias-pull-up: Enable pull-up resistor.
- bias-pull-down: Enable pull-down resistor.
- input-enable: Enable input from the pin.
- input-schmitt-enable: Enable input hysteresis.
- drive-strength: Set the drive strength of the pin, in milliamps. Possible
values are: 2, 4, 8, 12 (default: 4mA)
- slew-rate: If set to 0, slew rate is set to slow. If set to 1, it is set
to fast.
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"
&uart0 {
pinctrl-0 = <&uart0_default>;
pinctrl-1 = <&uart0_sleep>;
pinctrl-names = "default", "sleep";
};
Properties
Top level properties
These property descriptions apply to “raspberrypi,pico-pinctrl” nodes themselves. This page also describes child node properties in the following sections.
Properties not inherited from the base binding file.
(None)
Deprecated properties not inherited from the base binding file.
(None)
Properties inherited from the base binding file, which defines common properties that may be set on many nodes. Not all of these may apply to the “raspberrypi,pico-pinctrl” compatible.
Name |
Type |
Details |
|---|---|---|
|
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indicates the operational status of a device
Legal values: See Important properties for more information. |
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compatible strings
This property is required. See Important properties for more information. |
|
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register space
See Important properties for more information. |
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name of each register space
|
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interrupts for device
See Important properties for more information. |
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extended interrupt specifier for device
|
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name of each interrupt
|
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phandle to interrupt controller node
|
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Human readable string describing the device (used as device_get_binding() argument)
See Important properties for more information. This property is deprecated. |
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Clock gate information
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name of each clock
|
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number of address cells in reg property
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number of size cells in reg property
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DMA channels specifiers
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Provided names of DMA channel specifiers
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IO channels specifiers
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Provided names of IO channel specifiers
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mailbox / IPM channels specifiers
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Provided names of mailbox / IPM channel specifiers
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Power domain specifiers
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Provided names of power domain specifiers
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Number of cells in power-domains property
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Do not initialize device automatically on boot. Device should be manually
initialized using device_init().
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Property to identify that a device can be used as wake up source.
When this property is provided a specific flag is set into the
device that tells the system that the device is capable of
wake up the system.
Wake up capable devices are disabled (interruptions will not wake up
the system) by default but they can be enabled at runtime if necessary.
|
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Automatically configure the device for runtime power management after the
init function runs.
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List of power states that will disable this device power.
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Grandchild node properties
Name |
Type |
Details |
|---|---|---|
|
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An array of pins sharing the same group properties. Each
element of the array is an integer constructed from the
pin number and the alternative function of the pin.
This property is required. |
|
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The drive strength of a pin, in mA. The default value is 4mA, as this
is the power on reset value.
Default value: Legal values: |
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The slew rate of a pin. 0 corresponds to slow, and 1 corresponds to fast.
The default value is 0 (slow), as this is the power on reset value.
Legal values: |
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Override output-enable for a pin.
- 0 (RP2_GPIO_OVERRIDE_NORMAL) - drive output enable from selected
peripheral signal.
- 1 (RP2_GPIO_OVERRIDE_INVERT) - drive output enable from inverse of
selected peripheral signal.
- 2 (RP2_GPIO_OVERRIDE_LOW) - disable output.
- 3 (RP2_GPIO_OVERRIDE_HIGH) - enable output.
The default value is 0, as this is the power on reset value.
Legal values: |
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disable any pin bias
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enable pull-up resistor
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enable pull-down resistor
|
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enable input on pin (e.g. enable an input buffer, no effect on output)
|
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enable schmitt-trigger mode
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