Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762600Ab3IDNQr (ORCPT ); Wed, 4 Sep 2013 09:16:47 -0400 Received: from smtp-out-004.synserver.de ([212.40.185.4]:1189 "EHLO smtp-out-003.synserver.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754283Ab3IDNQp (ORCPT ); Wed, 4 Sep 2013 09:16:45 -0400 X-SynServer-TrustedSrc: 1 X-SynServer-AuthUser: lars@metafoo.de X-SynServer-PPID: 21105 Message-ID: <5227331A.5050507@metafoo.de> Date: Wed, 04 Sep 2013 15:18:18 +0200 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130827 Icedove/17.0.8 MIME-Version: 1.0 To: Mark Rutland CC: Lee Jones , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "jic23@cam.ac.uk" , "linux-iio@vger.kernel.org" , "linus.walleij@linaro.org" , "denis.ciocca@st.com" , "arnd@arndb.de" , broonie@kernel.org Subject: Re: [PATCH 11/11] iio: pressure-core: st: Provide correct regulator support References: <1378287103-21765-1-git-send-email-lee.jones@linaro.org> <1378287103-21765-12-git-send-email-lee.jones@linaro.org> <20130904131111.GJ18206@e106331-lin.cambridge.arm.com> In-Reply-To: <20130904131111.GJ18206@e106331-lin.cambridge.arm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2245 Lines: 55 On 09/04/2013 03:11 PM, Mark Rutland wrote: > Hi Lee, > > On Wed, Sep 04, 2013 at 10:31:43AM +0100, Lee Jones wrote: >> The power to some of the sensors are controlled by regulators. In most >> cases these are 'always on', but if not they will fail to work until >> the regulator is enabled using the relevant APIs. >> >> Signed-off-by: Lee Jones >> --- >> drivers/iio/pressure/st_pressure_core.c | 13 +++++++++++++ >> include/linux/iio/common/st_sensors.h | 3 +++ >> 2 files changed, 16 insertions(+) >> >> diff --git a/drivers/iio/pressure/st_pressure_core.c b/drivers/iio/pressure/st_pressure_core.c >> index f452417..7beed89 100644 >> --- a/drivers/iio/pressure/st_pressure_core.c >> +++ b/drivers/iio/pressure/st_pressure_core.c >> @@ -23,6 +23,7 @@ >> #include >> #include >> #include >> +#include >> #include >> >> #include >> @@ -315,6 +316,15 @@ int st_press_common_probe(struct iio_dev *indio_dev) >> indio_dev->modes = INDIO_DIRECT_MODE; >> indio_dev->info = &press_info; >> >> + /* Regulator not mandatory, but if requested we should enable it. */ >> + pdata->regulator = regulator_get(&indio_dev->dev, "vdd"); >> + if (!IS_ERR_OR_NULL(pdata->regulator)) { > > Can regulator_get return NULL? As far as I can see, it either returns a > valid reulator pointer or an ERR_PTR value. > > When you say "if requested", do you mean "if described in the dt"? If > so, the above doesn't distunguish between a regulator not being listed > and one failing to be got (e.g. if we got EPROBE_DEFER from > regulator_get). > > I think this would be better handled with something like Mark Brown's > suggested regulator_get_optional [1,2]. It can return NULL, but NULL is actually a valid regulator in that case, so the check should only be IS_ERR. And yes regulator_get_optional is what should be used here. - Lars -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/