Timers

[Matt]

I'm having some major headaches trying to get a timer working in my
driver.

The timer is started when the device node is opened, and deleted when it's
closed. The timer code itself calls mod_timer to add itself back in
again. At the moment, it runs every second and does nothing more than
issue a debug printk to say it's working okay.

The problem comes when I try and wrap the timer code inside some down()
and up() calls to make sure it's not fiddling with the hardware at the
same time as some other calls. When I do this, I get a huge oops which
goes right off my screen and I get the "Aieee..." message afterwards and I
have to push the reset button :(.

Should I be using spin_(un)lock_irqsave() calls anywhere instead of just a
semaphore? Or is there anything else I should be doing?

Cheers

Matt