[PATCH 1/2] coresight: etm4x: Expose default timestamp source in sysfs

[Leo Yan]

On Fri, Apr 29, 2022 at 01:30:59PM +0100, German Gomez wrote:
> Add a new sysfs interface in /sys/bus/coresight/devices/etm<N>/ts_source
> indicating the configured timestamp source when the ETM device driver
> was probed.
> 
> The perf tool will use this information to detect if the trace data
> timestamp matches the kernel time, enabling correlation of CoreSight
> trace with perf events.
> 
> Suggested-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> Signed-off-by: German Gomez <german.gomez at arm.com>

Reviewed-by: Leo Yan <leo.yan at linaro.org>