GPIO Driver

Author: Hunter Ross @hunteross

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Source: /crates/kernel/src/device/gpio.rs

This driver is used to configure the GPIO pins on the Raspberry Pi 4. The Raspberry Pi 4 has a total of 58 GPIO pins. GPIO configuration could be necessary in order to have other subsystems function correctly.

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API

set_function(&mut self, pin: u8, function: GpioFunction)

Sets the function for a specfic GPIO pin

For more information on different GPIO functions refer to section 5.3 of the bcm2711-peripherals datasheet

set_pull(&mut self, pin: u8, pull: GpioPull)

Configures the pull up / pull down resistor for a specific GPIO pin

set_pull_mask(&mut self, mask: u16, index: usize, pull: GpioPull)

Configures the pull up / pull down resistors for multiple pins. Pins are designated by providing an index referring to which set of pins we want configured (ie. 0-15, 15-31, etc.) and a bitmask: mask that determines which pins in that set we want to set the pull to.

add_event_detect(&mut self, pin: u8, event: GpioEvent)

Adds an event detect for a specific GPIO pin. When this event occurs an interrupt should be triggered.

check_event(&self, pin: u8) -> bool

Checks if an event was triggered for a specific GPIO pin

clear_event(&mut self, pin: u8)

Clears the event detection for a specific GPIO pin

check_any_event(&self) -> bool

Check if any event was triggered

clear_all_events(&mut self)

Clear event detection for all GPIO pins

set_high(&mut self, pin: u8)

Sets a GPIO pin high

set_low(&mut self, pin: u8)

Sets a GPIO pin low

toggle(&mut self, pin: u8)

Toggles a GPIO pin high -> low or low -> high

read(&self, pin: u8) -> bool

Read a GPIO pin value (1 or 0), returns a bool

read_mask(&self, index: usize) -> u32

Reads a mask of 32 pins, designate which set of pins you want with index

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For more information please refer to the bcm2711-peripherals datasheet