Re: [PATCH v2 04/11] leds: aw200xx: calculate dts property display_rows in driver

[George Stark]

Hello Andy

On 10/19/23 12:01, Andy Shevchenko wrote:
> On Wed, Oct 18, 2023 at 9:30 PM Dmitry Rokosov
> <ddrokosov@xxxxxxxxxxxxxxxxx> wrote:
> > From: George Stark <gnstark@xxxxxxxxxxxxxxxxx>
> >
> > Get rid of device tree property "awinic,display-rows" and calculate it
> > in driver using led definition nodes. display-row actually means number
> > of current switches and depends on how leds are connected to the device.
>
> Still the commit message does not answer the question why it's safe
> for the users that have this property enabled in their DTBs (note B
> letter).


> ...
>
> > +       device_for_each_child_node(dev, child) {
> > +               u32 source;
> > +               int ret;
> > +
> > +               ret = fwnode_property_read_u32(child, "reg", &source);
> > +               if (ret || source >= chip->cdef->channels)
>
> Perhaps a warning?
>
>      dev_warn(dev, "Unable to read from %pfw or apply a source channel
> number\n", child);

I skipped the warning intentionally because we have just the same loop 
several steps below and with the same check. There we have all proper 
warnings and aw200xx_probe_get_display_rows was intended to be short and 
lightweight. I'll redesign it to be even more simple.

> > +                       continue;
> > +
> > +               max_source = max(max_source, source);
> > +       }
>
> ...
>
> > +       chip->display_rows = max_source / chip->cdef->display_size_columns + 1;
> > +       if (!chip->display_rows) {
> > +               dev_err(dev, "No valid led definitions found\n");
> > +               return -EINVAL;
>
> So, this part is in ->probe() flow only, correct? If so,
>    return dev_err_probe(...);
>
> > +       }
>
> ...
>
> > +       if (aw200xx_probe_get_display_rows(dev, chip))
> > +               return -EINVAL;
>
> Why is the error code shadowed?

--
Best regards
George