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.. dtcompatible:: espressif,esp32-pinctrl
.. _dtbinding_espressif_esp32_pinctrl:

espressif,esp32-pinctrl
#######################

Vendor: :ref:`Espressif Systems <dt_vendor_espressif>`

Description
***********



.. code-block:: none

   Espressif's pin controller is in charge of controlling pin configurations, pin
   functionalities and pin properties as defined by pin states. In its turn, pin
   states are composed by groups of pre-defined pin muxing definitions and user
   provided pin properties.

   Each Zephyr-based application has its own set of pin muxing/pin configuration
   requirements. The next steps use ESP-WROVER-KIT's I2C_0 to illustrate how one
   could change a node's pin state properties. Though based on a particular board,
   the same steps can be tweaked to address specifics of any other target board.

   Suppose an application running on top of the ESP-WROVER-KIT board, for some
   reason it needs I2C_0's SDA signal to be routed to GPIO_33. When looking at
   that board's original device tree source file (i.e., 'esp_wrover_kit.dts'),
   you'll notice that the I2C_0 node is already assigned to a pre-defined state.
   Below is highlighted the information that most interests us on that file


       #include "esp_wrover_kit-pinctrl.dtsi"

       &i2c0 {
               ...
               pinctrl-0 = <&i2c0_default>;
               pinctrl-names = "default";
       };


   From the above excerpt, the pincrl-0 property is assigned the 'i2c0_default'
   state value. This and other pin states of the board are defined on another file
   (in this case, 'esp_wrover_kit-pinctrl.dtsi') on the same folder of the DTS file.
   Check below the excerpt describing I2C_0's default state on that file


       i2c0_default: i2c0_default {
               group1 {
                       pinmux = <I2C0_SDA_GPIO21>,
                                <I2C0_SCL_GPIO22>;
                       bias-pull-up;
                       drive-open-drain;
                       output-high;
               };
       };


   Only the 'pinmux' property above is actually required, other properties can
   be chosen if meaningful for the target application and, of course, supported
   by your target hardware. For example, some custom board may have an external
   pull-up resistor soldered to GPIO_21's pin pad, in which case, 'bias-pull-up'
   could be no longer required.

   Back to our fictional application, the previous I2C_0 state definition does not
   meet our expectations as we would like to route I2C_0's SDA signal to GPIO_33
   instead of to GPIO_21. To achieve it, we need to update the 'pinmux' property
   accordingly.

   Note that replacing 'I2C0_SDA_GPIO21' by 'I2C0_SDA_GPIO33' is very tempting and
   may even work, however, unless you have checked the hardware documentation first,
   it is not recommended. That's because there are no guarantees that a particular
   IO pin has the capability to route any specific signal.

   The recommendation is to check the pinmux macros definitions available for the
   target SoC in the following URL


   https://github.com/zephyrproject-rtos/zephyr/tree/main/include/zephyr/dt-bindings/pinctrl


   The ESP-WROVER-KIT board is based on the ESP32 SoC, in that case, we search
   through the file 'esp32-pinctrl.h' in the above URL. Luckily for us, there is
   one definition on that file that corresponds to our needs


       #define I2C0_SDA_GPIO33 \
               ESP32_PINMUX(33, ESP_I2CEXT0_SDA_IN, ESP_I2CEXT0_SDA_OUT)


   Now, we go back to edit 'esp_wrover_kit-pinctrl.dtsi' and create a new pin state
   on that file (or replace/update the one already defined) using the pinmux macro
   definition above, yielding


       i2c0_default: i2c0_default {
               group1 {
                       pinmux = <I2C0_SDA_GPIO33>,
                                <I2C0_SCL_GPIO22>;
                       bias-pull-up;
                       drive-open-drain;
                       output-high;
               };
       };


   With proper modifications, the same steps above apply when using different
   combinations of boards, SoCs, peripherals and peripheral pins.

   Note: Not all pins are available for a given peripheral, it depends if that
         pin supports a set of properties required by the target peripheral.

         When defining a state, the pin muxing information is constrained to
         the definitions at 'hal_espressif', however, pin properties (like
         bias-push-pull, drive-open-drain, etc) can be freely chosen, given the
         property is meaningful to the peripheral signal and that it is also
         available in the target GPIO.

         Another thing worth noting is that all pin properties should be grouped.
         All pins sharing common properties go under a common group (in the above
         example, all pins are in 'group1'). Other peripherals can have more than
         one group.

Properties
**********

Top level properties
====================


These property descriptions apply to "espressif,esp32-pinctrl"
nodes themselves. This page also describes child node
properties in the following sections.

.. tabs::

   .. group-tab:: Node specific properties

      Properties not inherited from the base binding file.

      (None)

   .. group-tab:: Deprecated node specific properties

      Deprecated properties not inherited from the base binding file.

      (None)

   .. group-tab:: Base properties

      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 "espressif,esp32-pinctrl" compatible.

      .. list-table::
         :widths: 1 1 4
         :header-rows: 1

         * - Name
           - Type
           - Details

         * - ``status``
           - ``string``
           - .. code-block:: none

                indicates the operational status of a device


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

             See :ref:`dt-important-props` for more information.

         * - ``compatible``
           - ``string-array``
           - .. code-block:: none

                compatible strings


             This property is **required**.

             See :ref:`dt-important-props` for more information.

         * - ``reg``
           - ``array``
           - .. code-block:: none

                register space


             See :ref:`dt-important-props` for more information.

         * - ``reg-names``
           - ``string-array``
           - .. code-block:: none

                name of each register space


         * - ``interrupts``
           - ``array``
           - .. code-block:: none

                interrupts for device


             See :ref:`dt-important-props` for more information.

         * - ``interrupts-extended``
           - ``compound``
           - .. code-block:: none

                extended interrupt specifier for device


         * - ``interrupt-names``
           - ``string-array``
           - .. code-block:: none

                name of each interrupt


         * - ``interrupt-parent``
           - ``phandle``
           - .. code-block:: none

                phandle to interrupt controller node


         * - ``label``
           - ``string``
           - .. code-block:: none

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



             See :ref:`dt-important-props` for more information.

             This property is **deprecated**.

         * - ``clocks``
           - ``phandle-array``
           - .. code-block:: none

                Clock gate information


         * - ``clock-names``
           - ``string-array``
           - .. code-block:: none

                name of each clock


         * - ``#address-cells``
           - ``int``
           - .. code-block:: none

                number of address cells in reg property


         * - ``#size-cells``
           - ``int``
           - .. code-block:: none

                number of size cells in reg property


         * - ``dmas``
           - ``phandle-array``
           - .. code-block:: none

                DMA channels specifiers


         * - ``dma-names``
           - ``string-array``
           - .. code-block:: none

                Provided names of DMA channel specifiers


         * - ``io-channels``
           - ``phandle-array``
           - .. code-block:: none

                IO channels specifiers


         * - ``io-channel-names``
           - ``string-array``
           - .. code-block:: none

                Provided names of IO channel specifiers


         * - ``mboxes``
           - ``phandle-array``
           - .. code-block:: none

                mailbox / IPM channels specifiers


         * - ``mbox-names``
           - ``string-array``
           - .. code-block:: none

                Provided names of mailbox / IPM channel specifiers


         * - ``wakeup-source``
           - ``boolean``
           - .. code-block:: none

                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``
           - .. code-block:: none


                Power domain the device belongs to.

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



         * - ``zephyr,pm-device-runtime-auto``
           - ``boolean``
           - .. code-block:: none

                Automatically configure the device for runtime power management after the
                init function runs.






Grandchild node properties
==========================

.. list-table::
   :widths: 1 1 4
   :header-rows: 1

   * - Name
     - Type
     - Details

   * - ``pinmux``
     - ``array``
     - .. code-block:: none

          Each array element represents pin muxing information of an individual
          pin. The array elements are pre-declared macros taken from Espressif's
          HAL.



       This property is **required**.

   * - ``bias-disable``
     - ``boolean``
     - .. code-block:: none

          disable any pin bias


   * - ``bias-pull-up``
     - ``boolean``
     - .. code-block:: none

          enable pull-up resistor


   * - ``bias-pull-down``
     - ``boolean``
     - .. code-block:: none

          enable pull-down resistor


   * - ``drive-push-pull``
     - ``boolean``
     - .. code-block:: none

          drive actively high and low


   * - ``drive-open-drain``
     - ``boolean``
     - .. code-block:: none

          drive with open drain (hardware AND)


   * - ``input-enable``
     - ``boolean``
     - .. code-block:: none

          enable input on pin (e.g. enable an input buffer, no effect on output)



   * - ``output-enable``
     - ``boolean``
     - .. code-block:: none

          enable output on a pin without actively driving it (e.g. enable an output
          buffer)



   * - ``output-low``
     - ``boolean``
     - .. code-block:: none

          set the pin to output mode with low level


   * - ``output-high``
     - ``boolean``
     - .. code-block:: none

          set the pin to output mode with high level