linux-kernel - Re: [RFT PATCH] power: bq2415x_charger: Properly handle ENODEV from power_supply_get_by

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Message-id: <1413382197.9555.0.camel@AMDC1943>
Date:	Wed, 15 Oct 2014 16:09:57 +0200
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Sebastian Reichel <sre@...nel.org>
Cc:	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: Re: [RFT PATCH] power: bq2415x_charger: Properly handle ENODEV from
 power_supply_get_by_phandle

On śro, 2014-10-15 at 15:58 +0200, Sebastian Reichel wrote:
> Hi,
> 
> On Wed, Oct 15, 2014 at 01:11:31PM +0200, Krzysztof Kozlowski wrote:
> > > [...] I guess something as the following is needed:
> > > 
> > > if (IS_ERR_OR_NULL(bq->notify_psy)) {
> > >     if (bq->notify_psy)
> > >         dev_err(&client->dev, "no 'ti,usb-charger-detection' property\n");
> > >     ret = PTR_ERR(bq->notify_psy);
> > >     goto error_2;
> > > }
> > 
> > So you do not want to defer the probe? What if notified charger will
> > come online after this probe?
> 
> No, but resources must be freed fore the EPROBE_DEFER case, too.
> You are right, though, that my snipped does not setup the
> EPROBE_DEFER return value correctly.
> 
> > Second idea - now I think my change is not compatible with bindings
> > (documentation) and could break booting of existing boards which do not
> > provide the "ti,usb-charger-detection" property. For example
> > arch/arm/boot/dts/omap3-n900.dts
> >
> > The "ti,usb-charger-detection" property is marked as optional but my
> > patch actually makes it required.
> > 
> > It should be rather like this:
> > 
> > if (IS_ERR(bq->notify_psy)) {
> >     bq->notify_psy = NULL;
> >     dev_info(&client->dev, "no 'ti,usb-charger-detection' property \n");
> > } else if (!bq->notify_psy) {
> >     ret = -EPROBE_DEFER;
> >     goto error_2;
> > }
> >
> > What do you think?
> 
> I thing the dev_info call should include the error code returned,
> since its not propagated further:
> 
> dev_info(&client->dev, "no 'ti,usb-charger-detection' property (err=%d)\n",
>          PTR_ERR(by->notify_psy));
> 
> Apart from that it looks fine to me. Can you send a v2?

Sure, I'll send fixed version.

Best regards,
Krzysztof
> 
> > [...]
> 
> -- Sebastian

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