GPIO interrupt custom callback data

[AnomalySmith]

Hi,

I just started looking around with the NRF52840 development kit and tried to implement simple GPIO interrupt based on the button sample.

I settled multiple GPIO pins configured in interrupt mode and wanted to use only one callback function to handle them but can't find a way to know which pin/device tree object has triggered the call.

I found that we might be able to do a relation between the last argument given to the callback handler (uint32_t pins, that seems to be pin mask value) but it really seems ugly to do so.

Am I missing something or do I have to declare/define dedicated callback function for each interrupt ?

Thanks !

[AnomalySmith]

For now, I've done something like this as a workaround to identify which pin triggered the common callback :/

#include <zephyr/zephyr.h>
#include <zephyr/drivers/gpio.h>
#include <math.h>


#define SW0_NODE DT_ALIAS(sw0)
#define SW1_NODE DT_ALIAS(sw1)

#if !DT_NODE_HAS_STATUS(SW0_NODE, okay)
#error "Unsupported board: sw0 devicetree alias is not defined"
#endif
#if !DT_NODE_HAS_STATUS(SW1_NODE, okay)
#error "Unsupported board: sw1 devicetree alias is not defined"
#endif

static const struct gpio_dt_spec swUp = GPIO_DT_SPEC_GET_OR(SW0_NODE, gpios, {0});
static const struct gpio_dt_spec swDown = GPIO_DT_SPEC_GET_OR(SW1_NODE, gpios, {0});

static struct gpio_callback swUp_cb_data;
static struct gpio_callback swDown_cb_data;

/* Interrupt routine: must be kept whithout blocking calls */
void btn_pressed(const struct device *dev, struct gpio_callback *cb, uint32_t pins) {

  if(pins == (uint32_t)pow(2, (double)swUp.pin)) { // It is SW0_NODE
    // Doing stuff
  } else if(pins == (uint32_t)pow(2, (double)swDown.pin)) { // It is SW1_NODE
    // Doing other stuff
  }
  // ...
}

int set_pin_int_cb(const struct gpio_dt_spec itr_pin, gpio_callback_handler_t cb, struct gpio_callback *itr_pin_cb_data) {
  // ...
  
  gpio_init_callback(itr_pin_cb_data, cb, BIT(itr_pin.pin));
  gpio_add_callback(itr_pin.port, itr_pin_cb_data);
}

void main(void) {
  
  set_pin_int_cb(swUp, &btn_pressed, &swUp_cb_data); // Initialising GPIO interrupt here as in basic/button sample
  set_pin_int_cb(swDown, &btn_pressed, &swDown_cb_data);
  
  while(1) { ... }

  return;
}

[Øivind]

Hi,

Yes, for a common callback you will have to use the pin mask to identify the pin. How you solve this is up to you.

A left shift:

pins & (1 << pin_num)

 
or BIT():

pins & BIT(pin_num)

 
are simple solutions.