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.bell...@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. -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
