Hi Tony,
On 06/03/20 11:44 PM, Tony Lindgren wrote:
> * Lokesh Vutla <lokeshvutla@xxxxxx> [200228 09:58]:
>> pwm_omap_dmtimer_disable() calls .stop callback which abruptly stops the
>> timer counter. This doesn't complete the current pwm cycle and
>> immediately disables the pwm. Instead disable the auto reload
>> functionality which allows to complete the current pwm cycle and then
>> disables the timer.
>>
>> Signed-off-by: Lokesh Vutla <lokeshvutla@xxxxxx>
>> ---
>> drivers/pwm/pwm-omap-dmtimer.c | 10 +++++++++-
>> 1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
>> index bc338619232d..89b3c25d02b8 100644
>> --- a/drivers/pwm/pwm-omap-dmtimer.c
>> +++ b/drivers/pwm/pwm-omap-dmtimer.c
>> @@ -93,8 +93,16 @@ static void pwm_omap_dmtimer_disable(struct pwm_chip *chip,
>> {
>> struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
>>
>> + /*
>> + * Disable auto reload so that the current cycle gets completed and
>> + * then the counter stops.
>> + */
>> mutex_lock(&omap->mutex);
>> - omap->pdata->stop(omap->dm_timer);
>> + omap->pdata->set_pwm(omap->dm_timer,
>> + pwm_get_polarity(pwm) == PWM_POLARITY_INVERSED,
>> + true, OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE,
>> + false);
>> +
>> mutex_unlock(&omap->mutex);
>> }
>
> I'm seeing an issue with this patch where after use something is
> left on and power consumption stays higher by about 30 mW after
> use.
Interesting...What is the PWM period and duty cycle in the test case?
Can you dump the following registers before and after disabling:
- TLDR
- TMAR
- TCLR
>
> I can reproduce this easily on droid4 with Sebastian's rumble-test
> app[0]. After use, I sometimes also hear the vibrator keep chirping
> quietly, so there seems to be some pwm still happening after disable :)
hmm..The line clearly goes down on the scope after the current pwm duty cycle is
done and never comes back.
>
> Reloading modules for pwm-vibra and pwm-omap-dmtimer make the power
> consumption go back down again.
>
> If you have a scope set up, maybe check the lines are quiet after
> disable after this patch?
>
> Regards,
>
> Tony
>
>
> [0] https://git.collabora.com/cgit/user/sre/rumble-test.git/plain/rumble-test.c
This is redirecting to collabora.com. Is this code available in github or some
public repo?
Thanks and regards,
Lokesh
