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gd,gd32-pinctrl-af

Vendor: GigaDevice Semiconductor

Description

The GD32 pin controller (AF model) 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/gd32f450i(g-i-k)xx-pinctrl.h>

  &pinctrl {
    /* configuration for the usart0 "default" state */
    usart0_default: usart0_default {
      /* group 1 */
      group1 {
        /* configure PA9 as USART0 TX and PA11 as USART0 CTS */
        pinmux = <USART0_TX_PA9>, <USART0_CTS_PA11>;
      };
      /* group 2 */
      group2 {
        /* configure PA10 as USART0 RX and PA12 as USART0 RTS */
        pinmux = <USART0_RX_PA10>, <USART0_RTS_PA12>;
        /* both PA10 and PA12 have pull-up enabled */
        bias-pull-up;
      };

    /* configuration for the usart0 "sleep" state */
    usart0_sleep: usart0_sleep {
      /* group 1 */
      group1 {
        /* configure PA9, PA10, PA11 and PA12 in analog mode */
        pinmux = <ANALOG_PA9>, <ANALOG_PA10>, <ANALOG_PA12>, <ANALOG_PA11>;
      };
    };

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. Similarly, 'usart0_sleep' child node encodes the pin configurations
for the sleep state (used in device low power mode). Note that analog mode
is used for low power states because it disconnects the pin pull-up/down
resistor, schmitt trigger, and output buffer.

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:

- drive-push-pull: Push-pull drive mode (default, not required).
- drive-open-drain: Open-drain drive mode.
- bias-disable: Disable pull-up/down (default, not required).
- bias-pull-up: Enable pull-up resistor.
- bias-pull-down: Enable pull-down resistor.
- slew-rate: Set the maximum speed (and so the slew-rate) of the output
  signal (default: 2MHz).

Note that drive and bias options are mutually exclusive.

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-1 = <&usart0_sleep>;
         pinctrl-names = "default", "sleep";
   };

Properties

Top level properties

These property descriptions apply to “gd,gd32-pinctrl-af” 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 “gd,gd32-pinctrl-af” compatible.

Name

Type

Details

status

string

indicates the operational status of a device

Legal values: 'ok', 'okay', 'disabled', 'reserved', 'fail', 'fail-sss'

See Important properties for more information.

compatible

string-array

compatible strings

This property is required.

See Important properties for more information.

reg

array

register space

See Important properties for more information.

reg-names

string-array

name of each register space

interrupts

array

interrupts for device

See Important properties for more information.

interrupts-extended

compound

extended interrupt specifier for device

interrupt-names

string-array

name of each interrupt

interrupt-parent

phandle

phandle to interrupt controller node

label

string

Human readable string describing the device (used as device_get_binding() argument)

See Important properties for more information.

clocks

phandle-array

Clock gate information

clock-names

string-array

name of each clock

#address-cells

int

number of address cells in reg property

#size-cells

int

number of size cells in reg property

dmas

phandle-array

DMA channels specifiers

dma-names

string-array

Provided names of DMA channel specifiers

io-channels

phandle-array

IO channels specifiers

io-channel-names

string-array

Provided names of IO channel specifiers

mboxes

phandle-array

mailbox / IPM channels specifiers

mbox-names

string-array

Provided names of mailbox / IPM channel specifiers

wakeup-source

boolean

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.

power-domain

phandle

Power domain the device belongs to.

The device will be notified when the power domain it belongs to is either
suspended or resumed.

Grandchild node properties

Name

Type

Details

slew-rate

string

Set the maximum speed of a pin. This setting effectively limits the
slew rate of the output signal. Defaults to "max-speed-2mhz", the SoC
default.

Default value: max-speed-2mhz

Legal values: 'max-speed-2mhz', 'max-speed-25mhz', 'max-speed-50mhz', 'max-speed-200mhz'

pinmux

array

An array of pins sharing the same group properties. The pins should
be defined using pre-defined macros or, alternatively, using the
GD32_PINMUX_AF or GD32_PINMUX_AFIO utility macros depending on the
pinmux model used by the SoC series.

This property is required.

bias-disable

boolean

disable any pin bias

bias-pull-up

boolean

enable pull-up resistor

bias-pull-down

boolean

enable pull-down resistor

drive-push-pull

boolean

drive actively high and low

drive-open-drain

boolean

drive with open drain (hardware AND)