From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751966AbaJOLLj (ORCPT ); Wed, 15 Oct 2014 07:11:39 -0400 Received: from mailout2.w1.samsung.com ([210.118.77.12]:24996 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751080AbaJOLLh (ORCPT ); Wed, 15 Oct 2014 07:11:37 -0400 MIME-version: 1.0 Content-type: text/plain; charset=UTF-8 X-AuditID: cbfec7f5-b7f776d000003e54-30-543e56657242 Content-transfer-encoding: 8BIT Message-id: <1413371491.26771.15.camel@AMDC1943> Subject: Re: [RFT PATCH] power: bq2415x_charger: Properly handle ENODEV from power_supply_get_by_phandle From: Krzysztof Kozlowski To: Sebastian Reichel Cc: Dmitry Eremin-Solenikov , David Woodhouse , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Date: Wed, 15 Oct 2014 13:11:31 +0200 In-reply-to: <20141015090512.GA26651@earth.universe> References: <1413275573-23014-1-git-send-email-k.kozlowski@samsung.com> <20141015090512.GA26651@earth.universe> X-Mailer: Evolution 3.10.4-0ubuntu2 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrPLMWRmVeSWpSXmKPExsVy+t/xK7qpYXYhBi+OalhMevKe2WLiysnM Fpd3zWGz+Nx7hNHi9O4SiwUbHzE6sHnsnHWX3WPzCi2PTas62Tw+b5ILYInisklJzcksSy3S t0vgyli36Q9rwWXRiuVd+9gaGNcLdjFyckgImEjM6XzIDmGLSVy4t56ti5GLQ0hgKaPE9M+z WUASvAKCEj8m3wOyOTiYBeQljlzKBgkzC6hLTJq3iBmi/jOjxLVr05kh6g0kFvZBDBUWyJLo /n0JLM4mYCyxefkSNhBbREBN4v2lpywgzcwCaxkl9n+/BVbEIqAq8frCBrAiTqDrjs2dxAyy WEigUGLiv0AQU0JAWaKx320Co8AsJNfNQrhuFpLrFjAyr2IUTS1NLihOSs810itOzC0uzUvX S87P3cQICeSvOxiXHrM6xCjAwajEw8txwDZEiDWxrLgy9xCjBAezkghvor9diBBvSmJlVWpR fnxRaU5q8SFGJg5OqQbGJR6NQUV+vYYXMh8tdDr73Kj/jdRKhu+db8+FXT736fPvVx+K3p5l a3V8FlRZ+EdcMeT70ZbcxlDvHF6PbbxSrxJmqi9hFEveL7Il90Dk/Y9ej9ceVr1+q+fUnC0s URPe63KevNPeqivCHXD89GR3HVGXquYWN4W3dbPft4qtV1MP0GXZ2a2txFKckWioxVxUnAgA Tt4KSEICAAA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On śro, 2014-10-15 at 11:05 +0200, Sebastian Reichel wrote: > Hi Krzysztof, > > On Tue, Oct 14, 2014 at 10:32:53AM +0200, Krzysztof Kozlowski wrote: > > The power_supply_get_by_phandle() on error returns ENODEV or NULL. > > The driver later expects obtained pointer to power supply to be > > valid or NULL. If it is not NULL then it dereferences it in > > bq2415x_notifier_call() which would lead to dereferencing ENODEV-value > > pointer. > > > > Properly handle the power_supply_get_by_phandle() error case and abort probe. > > > > Signed-off-by: Krzysztof Kozlowski > > Fixes: faffd234cf85 ("bq2415x_charger: Add DT support") > > Cc: > > That looks valid, but I guess this should change one more thing: > > > --- > > drivers/power/bq2415x_charger.c | 7 ++++++- > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/power/bq2415x_charger.c b/drivers/power/bq2415x_charger.c > > index e384844a1ae1..d9c457217b6a 100644 > > --- a/drivers/power/bq2415x_charger.c > > +++ b/drivers/power/bq2415x_charger.c > > @@ -1579,8 +1579,13 @@ static int bq2415x_probe(struct i2c_client *client, > > if (np) { > > bq->notify_psy = power_supply_get_by_phandle(np, "ti,usb-charger-detection"); > > > > - if (!bq->notify_psy) > > + if (!bq->notify_psy) { > > return -EPROBE_DEFER; > > this also needs to goto error_2. 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? 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? Krzysztof > > + } else if (IS_ERR(bq->notify_psy)) { > > + dev_err(&client->dev, "no 'ti,usb-charger-detection' property\n"); > > + ret = PTR_ERR(bq->notify_psy); > > + goto error_2; > > + } > > } > > else if (pdata->notify_device) > > bq->notify_psy = power_supply_get_by_name(pdata->notify_device); > > -- Sebastian