Re: [PATCH v2] pwm: iqs620a: Correct a stale state variable

[Jeff LaBundy <jeff@labundy.com>]

Hi Thierry,

Do you have any objection to applying Uwe's patch [1] followed by
this one so that they can land in 5.12?

Hi Uwe,

On Fri, Jan 22, 2021 at 07:12:39PM +0100, Uwe Kleine-König wrote:
> Hello,
> 
> On Mon, Jan 18, 2021 at 10:30:29PM -0600, Jeff LaBundy wrote:
> > If duty cycle is first set to a value that is sufficiently high to
> > enable the output (e.g. 10000 ns) but then lowered to a value that
> > is quantized to zero (e.g. 1000 ns), the output is disabled as the
> > device cannot drive a constant zero (as expected).
> > 
> > However if the device is later re-initialized due to watchdog bite,
> > the output is re-enabled at the next-to-last duty cycle (10000 ns).
> > This is because the iqs620_pwm->out_en flag unconditionally tracks
> > state->enabled instead of what was actually written to the device.
> > 
> > To solve this problem, use one state variable that encodes all 257
> > states of the output (duty_scale) with 0 representing tri-state, 1
> > representing the minimum available duty cycle and 256 representing
> > 100% duty cycle.
> > 
> > Signed-off-by: Jeff LaBundy <jeff@labundy.com>
> 
> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> 
> >  1 file changed, 37 insertions(+), 51 deletions(-)
> 
> Nice cleanup, thanks for picking up this idea.

Thank you for your kind words as well as your assistance throughout
this and other patches.

> 
> Best regards
> Uwe
> 
> -- 
> Pengutronix e.K.                           | Uwe Kleine-König            |
> Industrial Linux Solutions                 | https://www.pengutronix.de/ |

Kind regards,
Jeff LaBundy