lkml.org 
[lkml]   [2021]   [Jan]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v5 2/7] pwm: pca9685: Support hardware readout
Hello Clemens,

On Thu, Jan 14, 2021 at 06:16:22PM +0100, Clemens Gruber wrote:
> On Mon, Jan 11, 2021 at 09:35:32PM +0100, Uwe Kleine-König wrote:
> > My position here is: A consumer should disable a PWM before calling
> > pwm_put. The driver should however not enforce this and so should not
> > modify the hardware state in .free().
> >
> > Also .probe should not change the PWM configuration.
>
> I see. This would also allow PWMs initialized in the bootloader (e.g.
> backlights) to stay on between the bootloader and Linux and avoid
> flickering.
>
> If no one objects, I would then no longer reset period and duty cycles
> in the driver (and for our projects, reset them in the bootloader code
> to avoid leaving PWMs on after a kernel panic and watchdog reset, etc.)
>
> And if there is no pre-known state of the registers, we actually need
> the .get_state function fully implemented.

This sounds right.

Thanks
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2021-01-14 19:06    [W:0.097 / U:0.340 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site