Hi, Stefan
Stefan Roese wrote:
Felix,
On Wednesday 15 October 2008, Felix Radensky wrote:
I'm running Linux 2.6.26 on custom board based on AMCC 460EX.
I'm trying to catch interrupt generated by CPLD, but without any luck.
The interrupt is connected to GPIO 45. U-Boot (1.3.4) configures this
pin as external interrupt 12 (interrupt 20 in UIC 3). I've added the
following
entry to board device tree (in opb section)
[EMAIL PROTECTED],0 {
device_type = "cpld";
interrupts = <20 1>;
Is this interrupt active on rising edge? This is what you have configured
here. When you need level, active low, then you need to write:
interrupts = <20 8>;
And be careful which dts version you are using. Is this 20 decimal or hex?
The interrupt is indeed level, active low. Where can I find information
on UIC
interrupt settings for device tree ? I'm using dtc 1.2.0, 20 is decimal.
Is it ok ?
interrupt-parent = <&UIC3>;
};
In my driver I do the following:
/* Find CPLD node in device tree */
np = of_find_node_by_type(NULL, "cpld");
if (!np) {
printk(KERN_INFO "No CPLD found in device tree\n");
return -1;
}
/* Get and map irq number from device tree */
cpld_irq = irq_of_parse_and_map(np, 0);
if (cpld_irq == NO_IRQ) {
printk(KERN_ERR "irq_of_parse_and_map failed\n");
of_node_put(np);
return -ENODEV;
}
/* Register CPLD interrupt handler */
rc = request_irq(cpld_irq, cpld_interrupt,
IRQF_TRIGGER_LOW, "CPLD", NULL);
And I see this interrupt in /proc/interrups after loading
the driver. However interrupt handler is never invoked,
although hardware guys see that GPIO line goes down
when interrupt is generated.
What am I doing wrong ?
Another idea is that you didn't configure the pin multiplexing correctly. Most
external IRQ's are shared with other functions and/or GPIO's. You need to
configure the multiplexing correctly for external IRQ functionality. This is
usually done in U-Boot with the CFG_4xx_GPIO_TABLE.
I suggest you check here first.
I've checked that, here's the relevant line from u-boot:
{GPIO1_BASE, GPIO_IN , GPIO_ALT3, GPIO_OUT_0}, /* GPIO45 CS(5)
EOT/TC1 IRQ(12)*/
If I understand this code correctly, u-boot configures this line as ALT3
(which is external IRQ 12)
Thanks.
Felix.
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