zynq drivers/clocksource (was: Re: [GIT PULL] arm-soc: Xilinx zynq timer changes for v3.9)

[Michal Simek]

Hi,

here is origin comment from Arnd.

> Please have a look at the contents of the timer/cleanup and clocksource/cleanup
> branches in arm-soc, and merge them into your branch. If everything still
> works, you can add a patch on top of the merge to move your driver to
> drivers/clocksource and use the new infrastructure introduced there.

based on Arnd request I have looked at moving zynq timer code to the
new infrastructure
in drivers/clocksource. I have done some investigation and I am not quite
sure if I understand the design correctly.

I have looked at vt8500, tegra20 and bcm2835 drivers in arm-soc/for-next branch
and all of them use the same pattern with expectation that only
one timer with the same compatible property is available in the system.

I have done some tests on zynq and the problem is with calling
of_find_matching_node(NULL, .._match); which will always return the same
device_node which end up with faults later when you try to request the same
irq.

Is there any limitation/expectation that only one clocksource driver
should be probed?

Also not sure if make sense to add of_find_matching_node for architectures
which select CONFIG_OF or USE_OF when we can pass device_node directly from
of_find_matching_node().

Thanks,
Michal

-- 
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/
Maintainer of Linux kernel - Xilinx Zynq ARM architecture
Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform