Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1622229

[PATCH v3 0/1] pwm: pca9685: fix gpio-only operation.

Show all headers | View raw

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

Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

[PATCH v3 0/1] pwm: pca9685: fix gpio-only operation. Sven Van Asbroeck <thesven73@gmail.com> - 2017-04-12 17:20 +0200
  [PATCH v3 1/1] pwm: pca9685: fix gpio-only operation. Sven Van Asbroeck <thesven73@gmail.com> - 2017-04-12 17:20 +0200
    Re: [PATCH v3 1/1] pwm: pca9685: fix gpio-only operation. Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-04-13 10:20 +0200

csiph-web