Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754691AbcJOPKM (ORCPT ); Sat, 15 Oct 2016 11:10:12 -0400 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:48711 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751226AbcJOPKF (ORCPT ); Sat, 15 Oct 2016 11:10:05 -0400 Subject: Re: [PATCH] iio: light: ltr501: claim direct mode during select raw reads To: Alison Schofield References: <20161011195620.GA9539@d830.WORKGROUP> Cc: knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org From: Jonathan Cameron Message-ID: Date: Sat, 15 Oct 2016 16:10:03 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161011195620.GA9539@d830.WORKGROUP> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2587 Lines: 78 On 11/10/16 20:56, Alison Schofield wrote: > Driver was checking for direct mode but not locking it. Use > claim/release helper functions to guarantee the device stays > in direct mode during required raw read cases. > > Signed-off-by: Alison Schofield The uneven levels of the claim and release in the second case are nasty, please rework so that doesn't occur. It will work as it is, but I'm feeling fussy ;) Jonathan > --- > drivers/iio/light/ltr501.c | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) > > diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c > index 3afc53a..c2ac3cd 100644 > --- a/drivers/iio/light/ltr501.c > +++ b/drivers/iio/light/ltr501.c > @@ -631,14 +631,16 @@ static int ltr501_read_raw(struct iio_dev *indio_dev, > > switch (mask) { > case IIO_CHAN_INFO_PROCESSED: > - if (iio_buffer_enabled(indio_dev)) > - return -EBUSY; > - > switch (chan->type) { > case IIO_LIGHT: > + ret = iio_device_claim_direct_mode(indio_dev); > + if (ret) > + return ret; > + > mutex_lock(&data->lock_als); > ret = ltr501_read_als(data, buf); > mutex_unlock(&data->lock_als); > + iio_device_release_direct_mode(indio_dev); > if (ret < 0) > return ret; > *val = ltr501_calculate_lux(le16_to_cpu(buf[1]), > @@ -648,14 +650,16 @@ static int ltr501_read_raw(struct iio_dev *indio_dev, > return -EINVAL; > } > case IIO_CHAN_INFO_RAW: > - if (iio_buffer_enabled(indio_dev)) > - return -EBUSY; > + ret = iio_device_claim_direct_mode(indio_dev); > + if (ret) > + return ret; > > switch (chan->type) { > case IIO_INTENSITY: > mutex_lock(&data->lock_als); > ret = ltr501_read_als(data, buf); > mutex_unlock(&data->lock_als); > + iio_device_release_direct_mode(indio_dev); I don't like the releasing something in the case statement which was taken outside of it. Either bring the claim inside as you did above, or rework this to do the release after the switch for all paths. > if (ret < 0) > return ret; > *val = le16_to_cpu(chan->address == LTR501_ALS_DATA1 ? > @@ -665,11 +669,13 @@ static int ltr501_read_raw(struct iio_dev *indio_dev, > mutex_lock(&data->lock_ps); > ret = ltr501_read_ps(data); > mutex_unlock(&data->lock_ps); > + iio_device_release_direct_mode(indio_dev); > if (ret < 0) > return ret; > *val = ret & LTR501_PS_DATA_MASK; > return IIO_VAL_INT; > default: > + iio_device_release_direct_mode(indio_dev); > return -EINVAL; > } > case IIO_CHAN_INFO_SCALE: >