dts/bindings/pinctrl/ambiq,apollo3-pinctrl.yaml

# Copyright (c) 2023 Ambiq Micro Inc. <www.ambiq.com>
# SPDX-License-Identifier: Apache-2.0

description: |
  The Ambiq Apollo3 pin controller is a node responsible for controlling
  pin function selection and pin properties, such as routing a UART0 TX
  to pin 60 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/ambiq-apollo3-pinctrl.h>

  &pinctrl {
    uart0_default: uart0_default {
      group1 {
        pinmux = <UART0TX_P60>;
      };
      group2 {
        pinmux = <UART0RX_P47>;
        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.

compatible: "ambiq,apollo3-pinctrl"

include: base.yaml

child-binding:
  description: |
    Definitions for a pinctrl state.
  child-binding:

    include:
      - name: pincfg-node.yaml
        property-allowlist:
          - input-enable
          - drive-push-pull
          - drive-open-drain
          - bias-high-impedance
          - bias-pull-up
          - bias-pull-down

    properties:
      pinmux:
        required: true
        type: array
        description: |
          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.
      drive-strength:
        type: string
        enum:
          - "0.1"
          - "0.5"
          - "0.75"
          - "1.0"
        default: "0.1"
        description: |
          The drive strength of a pin, relative to full-driver strength.
          The default value is 0.1, which is the reset value of resigers
          PADREGx.PADnSTRNG and ALTPADCFGx.PADn_DS1.
      ambiq,pull-up-ohms:
        type: int
        enum:
          - 1500
          - 6000
          - 12000
          - 24000
        default: 1500
        description: |
          The 1.5K-24K pullup values are valid for select I2C enabled pads.
          For Apollo3 these pins are 0-1,5-6,8-9,25,27,39-40,42-43,48-49.
          The default value is 1500 ohms, which is the reset value of
          register PADREGx.PADxRSEL.
      ambiq,iom-nce-module:
        type: int
        default: 0
        description: |
          IOM nCE module select, selects the SPI channel (CE) number (0-3).
          The default value is 0, which is the reset value of
          register CFGx.GPIOnOUTCFG. If the pin is not a CE, this
          descriptor will be ignored.
      ambiq,iom-mspi:
        type: int
        default: 0
        description: |
          Indicates the module which uses specific CE pin, 1 if CE is IOM, 0 if MSPI.
          User should check g_ui8NCEtable in am_hal_gpio.c for the mapping
          information and config the pins accordingly, we give a default value
          0 here to make it be consistent with AM_HAL_GPIO_PINCFG_DEFAULT in
          ambiq hal. If the pin is not a CE, this descriptor will be ignored.
      ambiq,iom-num:
        type: int
        default: 0
        description: |
          Indicates the instance which uses specific CE pin.
          IOM number (0-5) or MSPI (0-2).
          User should check g_ui8NCEtable in am_hal_gpio.c for the mapping
          information and config the pins accordingly, we give a default value
          0 here to make it be consistent with AM_HAL_GPIO_PINCFG_DEFAULT in
          ambiq hal. If the pin is not a CE, this descriptor will be ignored.