Samr30/gpio: Erasing then write mux can generate spurious IRQ #19993
Description
Description
Erasing then write mux can generate spurious IRQ from another gpio sharing same extint
Steps to reproduce the issue
Example with PA6 and PB22 which share extint[6]:
void irq(void)
{
puts("IRQ");
}
int main(void)
{
gpio_init_int(GPIO_PIN(PA,6), GPIO_IN, GPIO_RISING, (gpio_cb_t)irq, NULL);
gpio_mux_t mux = GPIO_MUX_D;
gpio_t pin = GPIO_PIN(PB,22);
int pin_pos = _pin_pos(pin); // use _pin_pos from gpio.c
PortGroup* port = _port(pin); // use _port from gpio.c
while(1) {
xtimer_usleep(500000);
port->PMUX[pin_pos >> 1].reg &= ~(0xf << (4 * (pin_pos & 0x1)));
port->PMUX[pin_pos >> 1].reg |= (mux << (4 * (pin_pos & 0x1)));
}
return 0;
}
This code triggers some time (maybe 2sec, maybe 20sec) an IRQ on PA6!
I can confirm that the line PA6 stays to always 0 so there should not be any IRQ
I suggest to change https://github.com/RIOT-OS/RIOT/blob/2023.10-branch/cpu/sam0_common/periph/gpio.c#L147
void gpio_init_mux(gpio_t pin, gpio_mux_t mux)
{
PortGroup* port = _port(pin);
int pin_pos = _pin_pos(pin);
port->PINCFG[pin_pos].reg |= PORT_PINCFG_PMUXEN;
port->PMUX[pin_pos >> 1].reg &= ~(0xf << (4 * (pin_pos & 0x1)));
port->PMUX[pin_pos >> 1].reg |= (mux << (4 * (pin_pos & 0x1)));
}
by
void gpio_init_mux(gpio_t pin, gpio_mux_t mux)
{
PortGroup* port = _port(pin);
int pin_pos = _pin_pos(pin);
port->PINCFG[pin_pos].reg |= PORT_PINCFG_PMUXEN;
if (pin_pos & 1) {
port->PMUX[pin_pos >> 1].bit.PMUXO = mux;
} else {
port->PMUX[pin_pos >> 1].bit.PMUXE = mux;
}
}
Expected results
Set the mux without trigger an interrupt
Actual results
Trigger non desired interrupt
Versions
RIOT 2023-07