GPIO abstraction split into explicit input and output classes. More...

#include <cstdint>
#include <functional>
#include "non_copyable.hpp"

Include dependency graph for gpio.hpp:

This graph shows which files directly or indirectly include this file:

Classes
class	c7222::GpioIn
	GPIO input-only wrapper with pull configuration and optional IRQ. More...

struct	c7222::GpioIn::Config
	Configuration structure for input GPIO setup. More...

class	c7222::GpioOut
	GPIO output-only wrapper with output configuration and drive strength. More...

struct	c7222::GpioOut::Config
	Configuration structure for output GPIO setup. More...

Namespaces
namespace	c7222
	C7222 course abstractions namespace.

Enumerations
enum class	c7222::GpioPullMode { c7222::None , c7222::PullUp , c7222::PullDown }
	GPIO pull configuration. More...

enum class	c7222::GpioOutputType { c7222::HighZ , c7222::PushPull , c7222::OpenDrain }
	GPIO output type. More...

enum class	c7222::GpioDriveStrength { c7222::mA2 , c7222::mA4 , c7222::mA8 , c7222::mA12 }
	GPIO drive strength. More...

enum class	c7222::GpioInputEvent : uint32_t { c7222::None = 0x00 , c7222::LevelLow = 0x01 , c7222::LevelHigh = 0x02 , c7222::BothLevels = 0x03 , c7222::FallingEdge = 0x04 , c7222::RisingEdge = 0x08 , c7222::BothEdges = 0x0c , c7222::All = 0x0f }
	GPIO input event bitmask for IRQ configuration. More...

Detailed Description

GPIO abstraction split into explicit input and output classes.

Design principles:

Separate input and output roles: GpioIn and GpioOut are distinct classes. This prevents accidental misuse (e.g., writing to inputs or reconfiguring outputs as inputs) and keeps configuration options focused on what each direction actually needs.
Single ownership per pin: Each GPIO pin is owned by at most one GpioIn or GpioOut instance at a time. Platform backends track pin ownership and assert if a second object is constructed for the same pin.
Config-as-state: Each class has a Config struct that captures all relevant configuration fields. The object stores a cached config and Configure() reapplies it on the platform backend.
Minimal, explicit API: Inputs expose Read() and IRQ management; outputs expose Write() and Toggle(). This keeps the surface small for junior programmers and reduces ambiguous behaviors.

Platform integration (Raspberry Pi Pico W):

The Pico backend lives in platform/rpi_pico/gpio.cpp and maps these abstractions onto the Pico SDK (hardware/gpio.h).
Input handling:
- gpio_init() initializes the pin.
- Pull configuration uses gpio_disable_pulls, gpio_pull_up, or gpio_pull_down.
- Direction is set to input (GPIO_IN).
- Optional IRQs are enabled via gpio_set_irq_enabled_with_callback. The backend stores a per-pin map from GPIO number to a single GpioIn instance. This enforces one input object per pin and ensures a single callback dispatch target.
Output handling:
- gpio_set_drive_strength() applies pad drive strength.
- For push-pull output, the pin is set GPIO_OUT and driven high/low.
- For open-drain output, the SDK has no native open-drain mode; the backend emulates it by switching direction:
  - Drive low: set output low and GPIO_OUT.
  - Release high: set GPIO_IN (high-Z) so an external/internal pull-up can pull the line high.
- The backend tracks one GpioOut per pin and asserts on duplicates.

Platform integration (grader backend):

The grader backend provides stub implementations that compile and mirror the API shape without touching hardware.
It also enforces the same one-object-per-pin rule for consistency.

Classes