[MPC5200] using GPT's for interrupts

["Albrecht Dreß" <albrecht.dress@arcor.de>]

Hi all,

I currently try to use a MPC5200B GPT as interrupt source, which according to the comment at the start of arch/powerpc/platforms/52xx/mpc52xx_gpt.c is possible if the "interrupt-controller" and "#interrupt-cells = < 1 >" properties are added to the device tree node.

Apparently, /some/ work is done during startup, as I can see in the boot log:

[    0.438623] gpiochip_find_base: found new base at 251
[    0.444202] mpc52xx-gpt f0000650.timer: mpc52xx_gpt_irq_setup() complete. virq=78

In my driver, I identify the GPT node, call irq_of_parse_and_map() to get the irq number (which succeeds, with the same number as above), but unfortunately request_irq() or devm_request_irq() for this irq fail with error -22.  I tracked the failed call down to request_threaded_irq() which ejects because irq_settings_can_request(desc) returns false.

Before digging deeper into the code, maybe someone can tell me what I missed...  I'm using kernel 3.2.16.

Thanks in advance,
Albrecht.