Re: [PATCH v4 1/2] dt-bindings: leds-lp55xx: add ti,charge-pump-mode

[Maarten Zanders]

First off, bear with me here, I only recently started upstreaming 
patches to kernel. It still feels like navigating an extremely busy 
shipping lane... Either way, your feedback is highly valued.

On 2/2/23 14:15, Krzysztof Kozlowski wrote:
> > diff --git a/include/dt-bindings/leds/leds-lp55xx.h b/include/dt-bindings/leds/leds-lp55xx.h
> > new file mode 100644
> > index 000000000000..8f59c1c12dee
> > --- /dev/null
> > +++ b/include/dt-bindings/leds/leds-lp55xx.h
> > @@ -0,0 +1,10 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _DT_BINDINGS_LEDS_LP55XX_H
> > +#define _DT_BINDINGS_LEDS_LP55XX_H
> > +
> > +#define LP55XX_CP_OFF		0
> > +#define LP55XX_CP_BYPASS	1
> > +#define LP55XX_CP_BOOST		2
> > +#define LP55XX_CP_AUTO		3
> Additionally, these are not used, so it's a dead binding. Drop. Sorry,
> this is not the approach you should take.
>
> Best regards,
> Krzysztof
These definitions are intended to be used in the DTS's, so it seems 
normal to me that most of them go unused in the code? What am I missing?

As for the changes v2 > v3, this was based on input I got on v2 from Lee 
Jones, maintainer for leds, on the implementation of the parsing of this 
option:

> > +	pdata->charge_pump_mode = LP55XX_CP_AUTO;
> > +	ret = of_property_read_string(np, "ti,charge-pump-mode", &pm);
> > +	if (!ret) {
> > +		for (cp_mode = LP55XX_CP_OFF;
> > +		     cp_mode < ARRAY_SIZE(charge_pump_modes);
> > +		     cp_mode++) {
> > +			if (!strcasecmp(pm, charge_pump_modes[cp_mode])) {
> > +				pdata->charge_pump_mode = cp_mode;
> > +				break;
> > +			}
> > +		}
> > +	}
> A little over-engineered, no?
>
> Why not make the property a numerical value, then simply:
>
>    ret = of_property_read_u32(np, "ti,charge-pump-mode", &pdata->charge_pump_mode);
>    if (ret)
>            data->charge_pump_mode = LP55XX_CP_AUTO;

I found examples of similar configuration options of both types with 
other drivers in the kernel tree (ie string & uint8). I can appreciate 
both viewpoints but unfortunately cannot comply with both.


Best regards,
Maarten