This fixes test failures in tests/periph_timer_short_relative_set.
Note: This differs a bit from the implementation in e.g. nRF5x or STM32
in that it always briefly pauses the timer. The issue is that when
running the timer can take a few ticks to actually react to the new
compare target. So even if the previously written target is still in
the future, the timer may not fire anyway. Pausing the timer while
setting and setting the target at least one higher than the current
count reliably triggers the IRQ.
Previously, the callback was incorrectly passed a channel of zero as
argument regardless of the channel that triggered the IRQ. This fixes
the issue and also uses `bitarithm_test_and_clear()` to only iterate
over the channels that actually have an IRQ flag set, rather than
all channels.
The linter was unhappy that `unsinged long` and `uint32_t` were used
inconsistency (in the `timer_init()` declaration, implementation, as
well as in the `DEBUG()` format specifiers).
The QN908x CPU has several timer modules: one RTC (Real-Time Clock) that
can count from the 32kHz internal clock or 32.768 kHz external clock,
four CTIMER that use the APB clock and have four channels each and one
SCT timer with up to 10 channels running on the AHB clock.
This patch implements a timer driver for the CTIMER blocks only, which
is enough to make the xtimer module work. Future patches should improve
on this module to support using the RTC CNT2 32-bit free-running
counter unit and/or the SCT timer.
