On Mon, Aug 25, 2014 at 07:59:01PM +0800, Shawn Guo wrote: > On Wed, May 28, 2014 at 06:50:13PM +0800, Liu Ying wrote: > > The i.MX PWM version2 is embedded in several i.MX SoCs, > > such as i.MX27, i.MX51 and i.MX6SL. There is a 4-word(16bit) > > sample FIFO in this IP. Each FIFO slot determines the duty > > period of a PWM waveform in one full cycle. The IP spec > > mentions that we should not write a fourth sample because > > the FIFO will become full and triggers a FIFO write error > > (FWE) which will prevent the PWM from starting once it is > > enabled. In order to avoid any sample FIFO overflow issue, > > this patch clears all sample FIFO by doing software reset > > in the configuration hook when the controller is disabled > > or waits for a full PWM cycle to get a relinquished FIFO > > slot when the controller is enabled and the FIFO is fully > > loaded. > > > > The FIFO overflow issue can be reproduced by the following > > commands on the i.MX6SL EVK platform, assuming we use PWM2 > > for the debug LED which is driven by the pin HSIC_STROBE > > and the maximal brightness is 255. > > echo 0 > /sys/class/leds/user/brightness > > echo 0 > /sys/class/leds/user/brightness > > echo 0 > /sys/class/leds/user/brightness > > echo 0 > /sys/class/leds/user/brightness > > echo 255 > /sys/class/leds/user/brightness > > Here, FWE happens(PWMSR register reads 0x58) and the LED > > can not be lighten. > > > > Another way to reproduce the FIFO overflow issue is to run > > this script: > > while true; > > do echo 255 > /sys/class/leds/user/brightness; > > done > > > > Cc: Thierry Reding <[email protected]> > > Cc: Sascha Hauer <[email protected]> > > Cc: Shawn Guo <[email protected]> > > Cc: Lothar Waßmann <[email protected]> > > Cc: [email protected] > > Cc: [email protected] > > Signed-off-by: Liu Ying <[email protected]> > > The whole series, > > Acked-by: Shawn Guo <[email protected]> > > Thierry, > > Can you pick them up if they look good to you?
All three patches applied with your Acked-by (and some minor reformatting of the commit message). Thanks, Thierry
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