driver/pinctl: add pinctrl framework

Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>

Documentation/components/drivers/index.rst

@@ -178,6 +178,10 @@ Subdirectories of ``nuttx/drivers``
 
   Note Driver Support.
 
+* ``pinctrl/`` :doc:`special/pinctrl`
+
+  Configure and manage pin.
+
 * ``pipes/`` :doc:`special/pipes`
 
   FIFO and named pipe drivers.

Documentation/components/drivers/special/index.rst

@@ -48,6 +48,7 @@ following section.
   usrsock.rst
   mmcsd.rst
   net/index.rst
+  pinctrl.rst
   pipes.rst
   power/index.rst
   virtio.rst

Documentation/components/drivers/special/pinctrl.rst

@@ -0,0 +1,38 @@
+======================
+Pinctrl Device Drivers
+======================
+
+- The Pinctl driver framework allows applications and drivers to flexibly configure
+  and manage pin parameters such as functionality, strength, driver type, and slewrate
+  (voltage transition speed). This framework significantly enhances the flexibility
+  and configurability of the system in terms of hardware interface control.
+
+-  ``include/nuttx/pinctrl/pinctrl.h``
+   All structures and APIs needed to work with pinctrl drivers are provided in
+   this header file.
+
+-  ``struct pinctrl_dev_s`` and ``struct pinctrl_ops_s``.
+   Each pinctrl device driver must implement an instance of ``struct pinctrl_dev_s``.
+   And the ``struct pinctrl_ops_s`` defines a call table with the following methods:
+
+   #. **set_function**: Configures the pin's multiplexing (Mux) function, allowing it
+      to be set as a specific hardware interface (e.g., UART, SPI, I2C) or as a
+      general-purpose GPIO pin.
+   #. **set_strength**: Allows the user to configure the pin's drive strength to meet
+      the requirements of different hardware interfaces.
+   #. **set_driver**: Controls the pin's driver type, such as push-pull output or
+      open-drain output.
+   #. **set_slewrate**: Enables the configuration of pin slew rate, which is crucial
+      for high-speed digital signal transmission, optimizing signal rise and fall times.
+   #. **select_gpio**: Configures the pin function as GPIO.
+
+- Convenience macros are provided to map these operations directly:
+  ``PINCTRL_SETFUNCTION``,``PINCTRL_SETSTRENGTH``,``PINCTRL_SETDRIVER``,``PINCTRL_SETSLEWRATE``,
+  ``PINCTRL_SELECTGPIO``.
+
+- Application developers can configure and control pins by opening /dev/pinctrl0 nodes
+  and using the ioctl system call.
+  cmd: PINCTRLC_SETFUNCTION, PINCTRLC_SETSTRENGTH, PINCTRLC_SETDRIVER, PINCTRLC_SETSLEWRATE,
+  PINCTRLC_SELECTGPIO.
+  parameters: struct pinctrl_param_s.
+