Mika, I investigated what's required to suspend the device on remove,
by compiling as a module and running insmod/rmmod in various
circumstances.
As you suspected, pm_runtime_suspend() is unneccessary. I removed it,
and the chip is suspended ok when the module unloads. But this could be
because the pm_runtime refcnt is always zero when _remove() is called ?
When unloading the module (rmmod) :
If a gpio is still exported, the kernel unexports the gpio before calling
_remove().
If a pwm is still exported, the kernel refuses to rmmod the module. Even
'rmmod -f' does not work.
I am not sure if the kernel will ever call _unload() without releasing
the associated pwms/gpios. And if it ever does, I am also not sure how
we could convince pm_runtime to go to suspend.
v3:
remove unnecessary call to pm_runtime_suspend()
fix coding style for multi-line comment
(checkpatch.pl should ideally catch this, but did not?)
v2:
the pm_runtime framework controls the SLEEP bit, as suggested by
Mika Westerberg.
v1:
the SLEEP bit is always on.
Sven Van Asbroeck (1):
pwm: pca9685: fix gpio-only operation.
drivers/pwm/pwm-pca9685.c | 111 ++++++++++++++++++++++++++++++++--------------
1 file changed, 78 insertions(+), 33 deletions(-)
--
1.9.1
