Re: [PATCH v2 1/3] devicetree: mfd: Add binding for the TI LM3533

From: Bjorn Andersson
Date: Fri Oct 30 2015 - 15:42:01 EST


On Fri 30 Oct 11:42 PDT 2015, Lee Jones wrote:

Rob, please see the discussion regarding ti,boost-freq-khz below. Should
we both specify unit at the same time as we use standard units? (This is
not the first time I have to change this back and forth)

> On Tue, 27 Oct 2015, Bjorn Andersson wrote:
>
[..]
> > +- ti,hwen-gpios:
> > + Usage: required
> > + Value type: <prop-encoded-array>
> > + Definition: reference to gpio pin connected to the HWEN input; as
> > + specified in "gpio/gpio.txt"
>
> Why have you made this a vendor binding?
>
> *-gpios is a generic property.
>

Because the hwen gpio is a ti lm3533 specific thing, but I get what
you're saying. Will drop the prefix.

> > +- ti,als-supply:
> > + Usage: optional
> > + Value type: <prop-encoded-array>
> > + Definition: reference to regulator powering the V_als input; as
> > + specified in "regulator/regulator.txt"
>
> Same goes for *-supply.
>

Same here

> > +- ti,boost-freq-khz:
> > + Usage: required
> > + Value type: <u32>
> > + Definition: switch-frequency of the boost converter, must be either:
> > + 500 or 1000
>
> Quite a few vendors are using 'boost' now.
>

The ti,boost-low-freq from the bq25890 binding is the only other
property I can find that describes the same thing. So I'm not sure I
follow you here.

> Perhaps we need to create a set of generic bindings.
>
> Also, we usually measure DT bindings in HZ, not kHz.
>

I thought we had defined frequencies to be in HZ and HZ only, but then
Rob's comment that I need to actually specify the unit doesn't make any
sense.

Do we want these properties in a standard unit or do we want them
specifying the unit? Having both seems excessive.

> > +- ti,boost-ovp:
> > + Usage: required
> > + Value type: <u32>
> > + Definition: over voltage protection limit, must be one of: 16, 24, 32
> > + or 40
>
> Is this in volts? If so, it should be microvolts.
>

Okay, will update.

[..]
> > += ALS SUBNODE
> > +The als subnode must be named "als", it carries the als related properties.
>
> Perfect time to tell us what ALS is/means.
>

You're right, I'll expand this.

> > +- ti,als-resistance-ohm:
> > + Usage: required (unless ti,pwm-mode is specified)
> > + Value type: <u32>
> > + Definition: specifies the resistor value (R_als), in Ohm. Valid values
> > + ranges from 200kOhm to 1574Ohm.
>
> Might be worth specifying the values which you are actually going to
> use here i.e. "200kOhm" is not a valid u32.
>

I'll drop the units.

> > +- ti,pwm-mode:
> > + Usage: optional
> > + Value type: <empty>
> > + Definition: specifies, if present, that the als should operate in pwm
>
> Suggest s/pwm/PWM/
>

OK

[..]
> > +- ti,pwm-zones:
> > + Usage: optional
> > + Value type: <u32 list>
> > + Definition: lists the ALS zones to be PWM controlled for this backlight,
> > + the values in the list are in the range [0 - 4]
> > +
>
> It's usually a good idea to point to where all of the aforementioned
> generic properties are documented. I personally like the format
> (See: ../<subsystem>/<binding>.txt)
>

OK

> > += LED NODES

Regards,
Bjorn
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