Hi Tomasz,
Thanks for your comments.
> > +- #pwm-cells: Should be 3. Number of cells being used to specify PWM
> > property.
> > + First cell specifies the per-chip channel index of the PWM
> > to use, the
> > + second cell is the period in nanoseconds and bit 0 in
> > the third cell is
> > + used to encode the polarity of PWM output. Set bit
> > 0 of the third in PWM
> > + specifier to 1 for inverse polarity & set to 0
> > for normal polarity.
>
> If the meaning of flags cell is the same as in generic, default PWM
> specifier format, then it should be noted here and generic PWM binding
> documentation mentioned.
>
OK, How about the following ?
- #pwm-cells: Should be 3. See pwm.txt in this directory for a
description of the cells format.
I will replace it in v2.
> > +- fsl,pwm-clk-ps: the ftm0 pwm clock's prescaler,
> > divide-by 2^n(n = 0 ~ 7).
>
> Is it a hardware-specific property?
Yes, I will revise it in v2.
>
> > +- fsl,pwm-cpwm: Center-Aligned PWM (CPWM)
> > mode.
>
> Could you explain meaning of this property?
>
Well, this feature will be removed from the pwm core in v2.
> > +- fsl,pwm-number: the number of PWM devices, and is must equal to the
> > number + of "fsl,pwm-channels".
>
> This is redundant, because you can simply count how many entries have
> been specified in fsl,pwm-channels.
>
Yes, I will revise it in v2.
And this would be renamed to " fsl,pwm-channel-number", which can be more
Readable and understood.
> > +- fsl,pwm-channels: the channels' order which is be used for pwm in
> > ftm0 + module, and they must be one or some of 0 ~ 7, because the
> > ftm0 only has + 8 channels can be used.
>
> Could you explain meaning of this property more precisely? I'm interested
> especially how is this related to the PWM IP block and boards.
>
Yes.
There are 8 channels most. While the pinctrls of 4th and 5th channels could be
used by uart's Rx and Tx, then these 2 channels won't be used for pwm output,
so there will be 6 channels available by the pwm.
Thus, the pwm chip will register only 6 pwms(6 channels) most("fsl,pwm-channel-orders
= {0 1 2 3 6 7}").And also the "fsl,pwm-channel-number" will be 6.
If hasn't any other problems, I will revise It in v2.
And this will be renamed to "fsl,pwm-channel-orders", which can be more readable
and understood.
> > +- for very channel, the revlatived the pinctrl should be at least two
> ^ typo?
>
> > state + {"enN", "dsN"}, which "en" means "enable", "ds" means
> > "disable" and "N" + means the order of the channel.
>
> I'd suggest a more readable naming convention, for example chN-active and
> chN-idle. These words seem to be more common across existing bindings.
>
That's a good idea, I will think it over and revise it in v2.
Thanks very much.
--
Best Regards,
Xiubo
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