The existing debug log only mentions a state change, without providing
any details. For integration and stress-tests, it's helpful to see in
the dmesg log the reason for the state change.

The value is intended for power users and isn't converted as
human-readable values. But for the record each device has a 4-bit
status:

BIT(0): Unattached
BIT(1): Attached
BIT(2): Alert
BIT(3): Reserved (should not happen)

Example:

[  121.891288] intel-sdw intel-sdw.0: Slave status change: 0x2

<< this shows a Device0 Attached

[  121.891295] soundwire sdw-master-0: Slave attached, programming device number
[  121.891629] soundwire sdw-master-0: SDW Slave Addr: 30025d071101
[  121.891632] soundwire sdw-master-0: SDW Slave class_id 1, part_id 711, mfg_id 25d, unique_id 0, version 3
[  121.892011] intel-sdw intel-sdw.0: Msg ignored for Slave 0
[  121.892013] soundwire sdw-master-0: No more devices to enumerate
[  121.892200] intel-sdw intel-sdw.0: Slave status change: 0x21

<< this shows the device now Attached as Device1 and Unattached as
Device0, i.e. a successful enumeration.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210115053738.22630-3-yung-chuan.liao@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>