Hello,
I think there is a bug in i2c_pca_isa driver.
Problem is interrupt running on arm720 system linux-2.6.20.1.
Description of the problem:
When driver write to pc9564 an infinite loop interrupt appear (bloquing
the system).
J think it is because the acknowledge of interrupt is not do correctly.
Acknowledge of interrupt is done outside interrupt .
J think it is dangerous if latency time of interrupt is short (as in ARM
processor).
See existing code below:
static int pca_isa_waitforinterrupt(struct i2c_algo_pca_data *adap)
{
int ret = 0;
if (irq > -1)
{
ret = wait_event_interruptible(pca_wait,pca_isa_readbyte(adap,
I2C_PCA_CON) & I2C_PCA_CON_SI);
} else
{
while ((pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
udelay(100);
}
return ret;
}
static irqreturn_t pca_handler(int this_irq, void *dev_id) {
wake_up_interruptible(&pca_wait);
return IRQ_HANDLED;
}
Isa_wait is never waked because pca_handler is always call, because j
think it is necessary to acknowledge the interrupt in the interrupt
handler as usual.
My temporary solution is:
static irqreturn_t pca_handler(int this_irq, void *dev_id) {
disable_irq(irq); // !!!!!!!!!!!!!!!!!!! temporary patch
wake_up_interruptible(&pca_wait);
return IRQ_HANDLED;
}
How can we correct this ?
Thank to all
Alain Meirhaeghe
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