dts/bindings/pinctrl/telink,b91-pinctrl.yaml

# Copyright (c) 2022, Telink Semiconductor
# SPDX-License-Identifier: Apache-2.0

description: |
    The Telink B91 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 TX to pin PB2 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 pins and functions for the SoC used by the board */
      #include <dt-bindings/pinctrl/b91-pinctrl.h>

      &pinctrl {
        /* configuration for UART0 TX default state */
        uart0_tx_pb2_default: uart0_tx_pb2_default {
          /* configure PB2 as B91_FUNC_C */
          pinmux = <B91_PINMUX_SET(B91_PORT_B, B91_PIN_2, B91_FUNC_C)>;
        };
        /* configuration for UART0 RX default state */
        uart0_rx_pb3_default: uart0_rx_pb3_default {
          /* configure PB2 as B91_FUNC_C */
          pinmux = <B91_PINMUX_SET(B91_PORT_B, B91_PIN_3, B91_FUNC_C)>;
        };
      };

    The 'uart0_tx_pb2_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.

    A pin configuration can also specify pin properties such as the
    'bias-pull-up' property. Here is a list of supported standard pin
    properties:

    - bias-disable
    - bias-pull-down
    - bias-pull-up

    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_tx_pb2_default &uart0_rx_pb3_default>;
        pinctrl-1 = <&uart0_tx_pb2_sleep &uart0_rx_pb3_sleep>;
        pinctrl-names = "default", "sleep";
      };

compatible: "telink,b91-pinctrl"

include: base.yaml

properties:
  reg:
    required: true

  pad-mul-sel:
    type: int
    required: true
    description: |
        PinMux pad_mul_sel register value. Pin functions depend on it.

        For instance:
        Function C of PB2 configs the pin to UART0_TX if pad_mul_sel is set to <1>.
        But, the same function configs the same pin to DAC_I_DAT2_I if pad_mul_sel is set to <0>.

        Refer to the Telink TLSR9 specs to get more information about pins configuration.

child-binding:
  description: |
      This binding gives a base representation of the Telink B91 pins configuration.

  include:
  - name: pincfg-node.yaml
    property-allowlist:
    - bias-disable
    - bias-pull-down
    - bias-pull-up

  properties:
    pinmux:
      required: true
      type: int
      description: |
          Telink B91 pin's configuration (port, pin and function).