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SubjectRe: [PATCH v2 03/16] pwm: cros-ec: update documentation regarding pwm-cells
On Wed, Jan 17, 2018 at 10:29:53AM +0200, Claudiu Beznea wrote:
> With these changes, if pwm-cells=1 then only PWM-channel will be parsed,

I'm not sure if I'm understanding you correctly If cells is 1,
then your driver change just causes us not to parse correctly, and
everything fails.

> if it is 2 PWM-channel and PWM-period will be parsed, if pwm-cells=3
> then PWM-channel, PWM-period and PWM-flags will be parsed.
> In your driver you used to have only one cell because you wanted to allow
> user to give as argument only PWM channel, and you did not want a change
> of PWM period (and in of_xlate function you initialize pwm period with 0xffff
> value: this is why I changed the binding in patch 7 of this series, file

It's not a matter of "allow", it's a matter of description. The period
isn't actually even 0xffff, that's just a pseudo-period, to reflect that
you have a choice of duty cycles of 0 to 0xffff. I (justifiably, I
think) didn't think putting this false value in the device tree was

> rk3399-gru-kevin.dts). But e.g. sysfs could try to change the PWM period,
> there is no restriction to change the PWM period from sysfs, in the sysfs
> interface but the restriction is in PWM apply of the drive. The same things
> happens with these changes too. The user could introduce any PWM period via
> DT but the pwm apply function of the driver will return error.

sysfs has no bearing on a device tree binding. Just because we have a
broken interface here doesn't mean we should change how we describe the


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