SPI gpio interrupt on cs pin

[Dave-Poissant]

(Quick warning: I'm still new to embbeded and RTOSs (Zephyr included))

I'm trying to initiate an SPI communication between an STM32F411CE (slave) and an Arduino atmega 2560 (master) with an interrupt on the chip select pin and I can't seem to manage to get what I need for spi_transceive(...).

I'm configuring my interrupt callback as follow:

static const struct gpio_dt_spec cs = GPIO_DT_SPEC_GET_OR(SPI1_NODE, cs_gpios, {0});
static struct gpio_callback cs_callback;

void cs_enabled(const struct device *dev, struct gpio_callback *cb, uint32_t pins)
{
	SWOPrintf("Into SPI1 ISR\r\n");
        ...
}

void main(void)
{
	SWOPrintf("Starting \r\n");
	
	const struct device *spi_dev = device_get_binding(SPI1_LABEL);
	if (spi_dev == NULL) {...}
	ret = gpio_pin_interrupt_configure_dt(&cs,
					      GPIO_INT_EDGE_FALLING);
	if (ret != 0) {
		SWOPrintf("Error %d: failed to configure interrupt on %s pin %d\r\n",
			ret, cs.port->name, cs.pin);
		return;
	}
	gpio_init_callback(&cs_callback, cs_enabled, BIT(cs.pin));
	gpio_add_callback(cs.port, &cs_callback);
	while (1) {
		SWOPrintf("debug!\r\n");
		k_msleep(SLEEP_TIME_MS);
	}
}

I have an overlay file for my board configured as follow:

/ {
    aliases {
            i2c1node = &i2c1;
            i2c3node = &i2c3;
            spi1node = &spi1;
    };
};

&spi1 {
    pinctrl-names = "default";
    cs-gpios = <&gpioa 0x4 GPIO_ACTIVE_LOW>;
};

My problem is that the const struct device *dev in argument in interrupt callback will always be the cs struct which does not contains the information for the SPI1 device but for the gpio_chip_select_handler (which clearly doesn't work when sent in a spi_read(...) kind of function). Also, I can't seem to access static variables from inside the callback instance (so initialising the spi device * statically didn't work). Am I missing something in the configuration of a callback for an spi device? Is there any ways of adding parameters to a gpio callback?

I can give source code of both salve and master if needed.

Thank you in advance!

[erwango]

^^@FRASTM

[Dave-Poissant]

I've change the way I do it and instead of the gpio interrupt handling the spi_device, I make the gpio interrupt increment a given semaphore when the CS pin encounters a falling edge. By doing so, another dedicated thread waiting for the said semaphore can then use the semaphore and start an spi interraction.

This thread can be mark as answered.

[Dave-Poissant]

I can also provide some sources if necessary.

[ddemelier-ts]

Hi, I've tried to do this but the next spi_read_dt after acquiring the semaphore is blocking forever and I need an additional transaction from the master to unblock the slave on its spi_read_dt call. Did you get the same issue?