Messages in this thread | | | Date | Mon, 25 Aug 2014 14:35:50 +0200 | From | Thierry Reding <> | Subject | Re: [PATCH] PWM: atmel: fix incorrect CDTY value after enabling or disabling |
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On Mon, Aug 25, 2014 at 01:54:54PM +0200, Alexandre Belloni wrote: > Hi, > > On 25/08/2014 at 12:15:23 +0200, Thierry Reding wrote : > > On Fri, Mar 14, 2014 at 08:05:31PM +0100, Alexandre Belloni wrote: > > > pwm-leds calls .config() and .disable() in a row. This exhibits that it may > > > happen that the channel gets disabled before CDTY has been updated with CUPD. > > > The issue gets quite worse with long periods. > > > So, ensure by reading ISR that at least one period has past before disabling the > > > channel. > > > > > > The other issue is that it may happen that CUPD is not flushed before enabling > > > the channel so it will update CDTY/CPRD just after one period. So we always set > > > CUPD, even when the channel is not enabled. > > > > > > Tested on at91sam9g45 and sama5d31ek. > > > > > > Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> > > > --- > > > drivers/pwm/pwm-atmel.c | 46 +++++++++++++++++++++++++++++----------------- > > > 1 file changed, 29 insertions(+), 17 deletions(-) > > > > going through the list of unapplied patches I came across this old > > patch. It was never reviewed nor acked by anyone and you didn't ping me, > > so I always assumed it must no longer be required. Is that so? > > > > It is still required but Nicolas is not happy with the polling on > PWM_ISR and he was supposed to discuss that internally with the IP > designer to understand if there is a better way. > > I'll either ping on that one or send a new version when I'll know a bit > more.
Okay, thanks.
Thierry [unhandled content-type:application/pgp-signature] | |