From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from saturn.retrosnub.co.uk ([178.18.118.26]:50284 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932689AbdC2VQj (ORCPT ); Wed, 29 Mar 2017 17:16:39 -0400 Subject: Re: [RFC] staging: iio: ad7759: Replace mlock with driver private buf_lock To: Arushi Singhal , lars@metafoo.de References: <20170328173721.GA12157@arushi-HP-Pavilion-Notebook> Cc: Michael Hennerich , Hartmut Knaack , Peter Meerwald-Stadler , Greg Kroah-Hartman , linux-iio@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, outreachy-kernel@googlegroups.com From: Jonathan Cameron Message-ID: <4fd5df27-288b-f544-8860-4516ef52888f@kernel.org> Date: Wed, 29 Mar 2017 22:16:36 +0100 MIME-Version: 1.0 In-Reply-To: <20170328173721.GA12157@arushi-HP-Pavilion-Notebook> Content-Type: text/plain; charset=windows-1252 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 28/03/17 18:37, Arushi Singhal wrote: > The IIO subsystem is redefining iio_dev->mlock to be used by > the IIO core only for protecting device operating mode changes. > ie. Changes between INDIO_DIRECT_MODE, INDIO_BUFFER_* modes. > > In this driver, mlock was being used to protect hardware state > changes. Replace it with a buf_lock in the devices global data. > > Signed-off-by: Arushi Singhal Rule 1 of an RFC. Explain why it is an RFC rather than simply a patch. What needs comment here in particular? One thing that needs doing is a documentation update to reflect the additional elements buf_lock is now protecting. I think the use is sensible and can't otherwise see any issue with this patch. Thanks, Jonathan > --- > drivers/staging/iio/meter/ade7759.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/staging/iio/meter/ade7759.c b/drivers/staging/iio/meter/ade7759.c > index 0b65f1847510..514a4f6bb8f9 100644 > --- a/drivers/staging/iio/meter/ade7759.c > +++ b/drivers/staging/iio/meter/ade7759.c > @@ -429,7 +429,7 @@ static ssize_t ade7759_write_frequency(struct device *dev, > if (!val) > return -EINVAL; > > - mutex_lock(&indio_dev->mlock); > + mutex_lock(&st->buf_lock); > > t = 27900 / val; > if (t > 0) > @@ -447,10 +447,13 @@ static ssize_t ade7759_write_frequency(struct device *dev, > reg &= ~(3 << 13); > reg |= t << 13; > > - ret = ade7759_spi_write_reg_16(dev, ADE7759_MODE, reg); > + st->tx[0] = ADE7754_WRITE_REG(ADE7754_WAVMODE); > + st->tx[1] = reg; > + > + ret = spi_write(st->us, st->tx, 2); > > out: > - mutex_unlock(&indio_dev->mlock); > + mutex_unlock(&st->buf_lock); > > return ret ? ret : len; > } >