HACK: i2c: designware: Do nothing in system suspend/resume when RT suspended

Original thread: https://www.spinics.net/lists/linux-i2c/msg29413.html



There is possibility to enter dw_i2c_plat_suspend() callback twice
during system suspend under certain cases which is causing here warnings
from clk_core_disable() and clk_core_unprepare() as well as accessing the
registers that can be power gated.

Commit 8503ff16 ("i2c: designware: Avoid unnecessary resuming during
system suspend") implemented a prepare callback that checks for runtime
suspended device which allow PM core to set direct_complete flag and
skip system suspend and resume callbacks.

However it can still happen if nothing resumes the device prior system
syspend (e.g. acpi_subsys_suspend()) and there is a slave device which
unsets the direct_complete flag of the parent in __device_suspend() thus
causing PM code to not skip the system suspend/resume callbacks.

Avoid this by checking runtime status in suspend and resume callbacks
and return directly if device is runtime suspended. This affects only
system suspend/resume since during runtime suspend/resume runtime status
is suspending (not suspended) or resuming.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>