timer: Add wait_us/wait_ms helper macros to wait for conditions

A very common pattern in drivers is that we need to wait for a condition
to become true (e.g. for a lock bit in a PLL status register to become
set), but we still want to have a maximum timeout before we treat it as
an error. coreboot uses the stopwatch API for this, but it's still a
little verbose for the most simple cases. This patch introduces two new
helper macros that wrap this common application of the stopwatch API in
a single line: wait_ms(XXX, YYY) waits for up to XXX milliseconds to see
if the C condition 'if (YYY)' becomes true. The return value is 0 on
failure (i.e. timeout expires without the condition becoming true) and
the amount of elapsed time on success, so it can be used both in a
boolean context and to log the amount of time waited.

Replace the custom version used in an MTK ADC driver with this new
generic version.

Change-Id: I6de38ee00673c46332ae92b8a11099485de5327a
Signed-off-by: Tristan Shieh <tristan.shieh@mediatek.com>
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/29315
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

0 files changed, 0 insertions, 0 deletions