Hi Guenter,
On 21 May 2015 at 23:59, Guenter Roeck linux@roeck-us.net wrote:
On Thu, May 21, 2015 at 11:46:53PM +0800, Fu Wei wrote:
Hi Guenter,
[ ... ]
/** Try to determine the frequency from the arch_timer interface*/clk = arch_timer_get_rate();arch_timer_get_rate() does not seem to be exported. Did you try to build the driver as module ?
yes, I have built it as a ko module, that is why I made a patch to export this interface in the first patch of this patchset
but I will confirm it again :-)
Guess I'll give it a try myself. I don't really understand how this can work unless arch_timer_get_rate() is exported in your tree.
yes, I have exported it , I think it make sense to export it. Because other driver maybe need to get system counter info
Do you agree ? :-)
I don't think it is for me to agree or not. The arm maintainers will need to be involved. You can not just export such a function without maintainer Ack.
yes, I have added Mark Rutland in the CC list when I sent this patchset . He added the "arch_timer_get_rate();" in the arch timer driver. See if he can provide some suggestion. :-)
maybe I should add some more arm arch timer maintainers to get more help on this :-)
Having said that, my personal preference would be for the counter and rate to be exported through the clock subsystem (ie with clk_get_rate). But that would still not provide the current counter value, so maybe that isn't even possible.
I will try to make a patch for this, If the arm maintainers don't like exporting "arch_timer_get_rate();"
But your thought is good, the clk_get_rate is the best way to do for now
Thanks, Guenter