39 lines
1.9 KiB
ReStructuredText
39 lines
1.9 KiB
ReStructuredText
======================
|
|
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.
|
|
|