layout	title	parent
post	4.2 Commands	4. GPIO

Useful API pages:

Functions table

Function	Description
gpio_pin_configure	Configure a single pin
gpio_pin_interrupt_configure	Configure pin interrupt
gpio_pin_get	Get logical level of an input pin - taking into account the GPIO_ACTIVE_LOW flag. If pin is configured as Active High, a low physical level will be interpreted as logical value 0. If pin is configured as Active Low, a low physical level will be interpreted as logical value 1.
gpio_pin_set	Set logical level of an output pin taking into account GPIO_ACTIVE_LOW flag. Value 0 sets the pin in logical 0 / inactive state. Any value other than 0 sets the pin in logical 1 / active state. If pin is configured as Active High, the default, setting it in inactive state will force the pin to a low physical level. If pin is configured as Active Low, setting it in inactive state will force the pin to a high physical level.
gpio_pin_toggle	Toggle pin level

Callback functions: (not covered in exercises)

Function	Description
gpio_init_callback	Helper to initialize a struct `gpio_callback` properly
gpio_add_callback	Add an application callback
gpio_remove_callback	Remove an application callback

Device Driver Model

Function	Description
device_get_binding	Retrieve the device structure for a driver by name. Device objects are created via the DEVICE_DEFINE() macro and placed in memory by the linker. If a driver needs to bind to another driver it can use this function to retrieve the device structure of the lower level driver by the name the driver exposes to the system.

Flags table

Input/Output configuration options:

Flags	Description
GPIO_INPUT	Enables pin as input
GPIO_OUTPUT	Enables pin as output, no change to the output state
GPIO_DISCONNECTED	Disables pin for both input and output.
GPIO_OUTPUT_LOW	Configures GPIO pin as output and initializes it to a low state.
GPIO_OUTPUT_HIGH	Configures GPIO pin as output and initializes it to a high state.
GPIO_OUTPUT_INACTIVE	Configures GPIO pin as output and initializes it to a logic 0.
GPIO_OUTPUT_ACTIVE	Configures GPIO pin as output and initializes it to a logic 1.

GPIO interrupt configuration flags

Flags	Description
GPIO_INT_DISABLE	Disables GPIO pin interrupt.
GPIO_INT_EDGE_RISING	Configures GPIO interrupt to be triggered on pin rising edge and enables it.
GPIO_INT_EDGE_FALLING	Configures GPIO interrupt to be triggered on pin falling edge and enables it.
GPIO_INT_EDGE_BOTH	Configures GPIO interrupt to be triggered on pin rising or falling edge and enables it.
GPIO_INT_LEVEL_LOW	Configures GPIO interrupt to be triggered on pin physical level low and enables it.
GPIO_INT_LEVEL_HIGH	Configures GPIO interrupt to be triggered on pin physical level high and enables it.
GPIO_INT_EDGE_TO_INACTIVE	Configures GPIO interrupt to be triggered on pin state change to logical level 0 and enables it.
GPIO_INT_EDGE_TO_ACTIVE	Configures GPIO interrupt to be triggered on pin state change to logical level 1 and enables it.
GPIO_INT_LEVEL_INACTIVE	Configures GPIO interrupt to be triggered on pin logical level 0 and enables it.
GPIO_INT_LEVEL_ACTIVE	Configures GPIO interrupt to be triggered on pin logical level 1 and enables it.

GPIO pin active level flags

Flags	Description
GPIO_ACTIVE_LOW	GPIO pin is active (has logical value ‘1’) in low state.
GPIO_ACTIVE_HIGH	GPIO pin is active (has logical value ‘1’) in high state.

Defines

Flags	Description
GPIO_INT_DEBOUNCE	Enable GPIO pin debounce
GPIO_DT_SPEC_GET_BY_IDX	This returns a static initializer for a `gpio_dt_spec` structure given a devicetree node identifier, a property specifying a GPIO and an index.

Flags	Description
DT_ALIAS	Get a node identifier from /aliases.
DT_GPIO_LABEL	Get a label property from a gpio phandle-array property (at index 0)
DT_GPIO_PIN	Get a GPIO specifier’s pin cell (at index 0)
DT_GPIO_FLAGS	Get a GPIO specifier’s flags cell (at index 0)

Additional flag categories can be found here: