On Tue, 4 Jul 2017, Dong Aisheng wrote:
> IMX Timer/PWM Module (TPM) supports both timer and pwm function while
> this patch only adds the timer support. PWM would be added later.
>
> The TPM counter, compare and capture registers are clocked by an
> asynchronous clock that can remain enabled in low power modes.
>
> Due to the possible bus fabric contention, the CNT write may
> take a few more cycles and we need add ETIME check in case current
> delta event program gets missed.
>
> Cc: Daniel Lezcano <[email protected]>
> Cc: Arnd Bergmann <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Shawn Guo <[email protected]>
> Cc: Anson Huang <[email protected]>
> Cc: Bai Ping <[email protected]>
> Signed-off-by: Dong Aisheng <[email protected]>
>
> ---
> ChangeLog:
> v2->v3:
> * address all comments from Daniel Lezcano
> * add more explaination on ETIME check in commit message
Actually the logic wants to be explained in a comment inside the function
as well.
I'm really impressed, that 10 years after we discovered the HPET disaster
(See comment in arch/x86/kernel/hpet.c::hpet_next_event) the same hardware
idiocy comes around again....
Thanks,
tglx
