Existing devices and implementations only support the required CLOCK_STOP_MODE0. All the code related to CLOCK_STOP_MODE1 has not been tested and is highly questionable, with a clear confusion between CLOCK_STOP_MODE1 and the simple clock stop state machine.
This patch removes all usages of CLOCK_STOP_MODE1 - which has no impact on any solution - and fixes the use of the simple clock stop state machine. The resulting code should be a lot more symmetrical and easier to maintain.
Note that CLOCK_STOP_MODE1 is not supported in the SoundWire Device Class specification so it's rather unlikely that we need to re-add this mode later.
If a device lost sync and can no longer ACK a command, it may not be able to enter a lower-power state but it will still be able to resync when the clock restarts. In those cases, we want to continue with the clock stop sequence.
This patch modifies the behavior during clock stop sequences to only log errors unrelated to -ENODATA/Command_Ignored. The flow is also modified so that loops continue to prepare/deprepare other devices even when one seems to have lost sync.
When resuming the clocks, all issues are logged with a dev_warn(), previously only some of them were checked. This is the only part that now differs between the clock stop entry and clock stop exit sequences: while we don't want to stop the suspend flow, we do want information on potential issues while resuming, as they may have ripple effects.
For consistency the log messages are also modified to be unique and self-explanatory. Errors in sdw_slave_clk_stop_callback() were removed, they are now handled in the caller.
Pierre-Louis Bossart (4): soundwire: bus: only use CLOCK_STOP_MODE0 and fix confusions soundwire: add missing kernel-doc description soundwire: bus: handle -ENODATA errors in clock stop/start sequences soundwire: bus: add missing \n in dynamic debug
drivers/soundwire/bus.c | 155 +++++++++++++++------------------- include/linux/soundwire/sdw.h | 3 +- 2 files changed, 70 insertions(+), 88 deletions(-)