linux-kernel - Re: [PATCH 3/3] regulator: core: make regulator_register() EPROBE

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Message-ID: <20190918160648.6qvdzvnflyly5xft@pengutronix.de>
Date:   Wed, 18 Sep 2019 18:06:48 +0200
From:   Marco Felsch <m.felsch@...gutronix.de>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     ckeepax@...nsource.cirrus.com, lkml <linux-kernel@...r.kernel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Doug Anderson <dianders@...omium.org>,
        Mark Brown <broonie@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>, zhang.chunyan@...aro.org
Subject: Re: [PATCH 3/3] regulator: core: make regulator_register()
 EPROBE_DEFER aware

On 19-09-18 08:53, Dmitry Torokhov wrote:
> On Wed, Sep 18, 2019 at 1:18 AM Marco Felsch <m.felsch@...gutronix.de> wrote:
> >
> > On 19-09-17 17:57, Dmitry Torokhov wrote:
> > > On Tue, Sep 17, 2019 at 4:42 PM Marco Felsch <m.felsch@...gutronix.de> wrote:
> > > >
> > > > Sometimes it can happen that the regulator_of_get_init_data() can't
> > > > retrieve the config due to a not probed device the regulator depends on.
> > > > Fix that by checking the return value of of_parse_cb() and return
> > > > EPROBE_DEFER in such cases.
> > >
> > > Treating EPROBE_DEFER in a special way is usually wrong.
> > > regulator_of_get_init_data() may fail for multiple reasons (no memory,
> > > invalid DT, etc, etc). All of them should abort instantiating
> > > regulator.
> >
> > Those errors are handled but the behaviour of this funciton is to return
> > NULL in such errors which is fine for the caller of this function. I
> > only want to handle EPROBE_DEFER special..
> 
> And I am saying it is wrong to handle only EPROBE_DEFER.
> regulator_of_get_init_data() should always return ERR_PTR()-encoded
> error code when parsing callback returns error, so that regulator core
> does not mistakenly believe that there is no configuration/init data
> when in fact there is, but we failed to handle it properly.
> 
> IOW I'm advocating for extending you patch so that it reads:
> 
> +               ret = desc->of_parse_cb(child, desc, config);
> +               if (ret) {
> +                       of_node_put(child);
> +                       return ERR_PTR(ret);
> +               }

I know what you mean but I wanted to keep the core changes minimal and I
tought that it was intentional by the core.

Regards,
  Marco

> Thanks.
> 
> -- 
> Dmitry
> 
> 

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