Hi everybody,
For my project, I need to use the PA0 pin as an interrupt to handle
the \int pin of the pcf8574 chip (which is a I2C-8-bit controller). I
have used the work done by calzo(Foxdoc.pdf on lugman.net, thank's to
him).
I succeed in building the module and the IRQ is well requested. To do
that, I have to invert the \int pin of the pcf8574.
The problem I have is that the interrupt is handeld on the high state
(and not on the front), so, when a logic state change on the pcf8574,
the PA0 pin goes to high, and it generates thousand of interrupts,
whereas I need only one.
Here is the code made by Calzo :
#include <linux/interrupt.h>
#include <linux/module.h>
#include <asm/io.h> //provide access to GPIO port and other
MODULE_LICENSE("DUAL GPL/BSD");
MODULE_VERSION("0.1");
#define IRQ_PA_MASK 0x01 //interrupt sul pulsante
static DEFINE_SPINLOCK(gpio_lock_irq);
/***** FUNZIONE DI INTERRUPT ******
* In questa funzione viene disabilitata temporaneamente la
* possibilità di ricevere altri interrupt fino a che non è
* soddisfatta la funzione seguente
* ********************************/
static irqreturn_t
irqPA_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
*R_IRQ_MASK1_CLR = 0;
*R_PORT_PA_DATA = 0; //fondamentale!
printk(KERN_ALERT "calzo - irq servito\n");
return IRQ_HANDLED;
}
/****************************************
* INITIALIZATION & CLEANUP functions
****************************************/
/// Funzione di inizializzazione del modulo
int irqPA_init_module(void) {
if (request_irq(PA_IRQ_NBR, irqPA_interrupt,
SA_INTERRUPT,"calzo gpio PA interrupt", NULL))
{
printk(KERN_CRIT "err: PA irq for gpio (calzo)\n");
return -ERESTART;
}
//setto su quale pin vi è línterrupt valido
*R_IRQ_MASK1_SET = IRQ_PA_MASK;
return 0;
}
///Funzione di scaricamento del modulo
void irqPA_cleanup_module(void) {
spin_lock_irq(&gpio_lock_irq);
*R_IRQ_MASK1_SET = 0;
*R_IRQ_MASK1_CLR = 0;
free_irq(PA_IRQ_NBR, NULL);
spin_unlock_irq(&gpio_lock_irq);
}
/***************************************
* INIT & EXIT
***************************************/
module_init(irqPA_init_module);
module_exit(irqPA_cleanup_module);
Do you understand my problem? And do you see how to disable the irq
once one is received?
Thank's in advance.
Maxime Coquelin
