i.MX Processors中的主题 Re: Which HW timer is associated to in timer_create()

Which HW timer is associated to in timer_create()

rans — Wed, 10 Jan 2018 16:58:54 GMT

Hello,

I try to understand how to use HW timers from linux userspace.

Is it by calling timer_create ? If yes - which timer number is associated to it ?

Thank you,

Ran

Re: Which HW timer is associated to in timer_create()

Carlos_Musich — Tue, 16 Jan 2018 23:06:47 GMT

Hi rashalit,

you may find useful the following threadReg: Using Timers in IMX

Regards,
Carlos

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Re: Which HW timer is associated to in timer_create()

rans — Wed, 17 Jan 2018 06:11:07 GMT

Hi Carlos,

I've checked the link but it did not help a lot.

I need one HW timer in userspace.

If linux timer_create() is actually using that HW timer than it is good enough.

What I asked before is if timer_create actually using a HW timer (and not just Linux' tick for example which has less precision).

Thank you,

Ran

Re: Which HW timer is associated to in timer_create()

JayTu — Wed, 17 Jan 2018 07:09:07 GMT

timer_create() used hrtimer that is high res timer. When the board starts, BSP will pass hw timer to kernel that will be used by hrtimer.

kernel_imx/kernel/time/posix-timers.c

static int common_timer_create(struct k_itimer *new_timer)
{
 hrtimer_init(&new_timer->it.real.timer, new_timer->it_clock, 0);
 return 0;
}‍‍‍‍‍