From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:41726 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754169AbdG3Q5q (ORCPT ); Sun, 30 Jul 2017 12:57:46 -0400 Date: Sun, 30 Jul 2017 17:57:42 +0100 From: Jonathan Cameron To: Akinobu Mita Cc: linux-iio@vger.kernel.org, Daniel Baluta Subject: Re: [PATCH v3 01/11] iio: adc: ti-ads1015: fix incorrect data rate setting update Message-ID: <20170730175742.03c240fd@kernel.org> In-Reply-To: <1501427575-31045-2-git-send-email-akinobu.mita@gmail.com> References: <1501427575-31045-1-git-send-email-akinobu.mita@gmail.com> <1501427575-31045-2-git-send-email-akinobu.mita@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On Mon, 31 Jul 2017 00:12:45 +0900 Akinobu Mita wrote: > The ti-ads1015 driver has eight iio voltage channels and each iio channel > can hold own sampling frequency information. > > The ADS1015 device only have a single config register which contains an > input multiplexer selection, PGA and data rate settings. So the driver > should load the correct settings when the input multiplexer selection is > changed. > > However, regardless of which channlel is currently selected, changing any > iio channel's sampling frequency information immediately overwrites the > current data rate setting in the config register. > > It breaks the current data rate setting if the different channel's sampling > frequency information is changed because the data rate setting is not > reloaded when the input multiplexer is switched. > > This removes the unexpected config register update and correctly load the > data rate setting before getting adc result. > > Cc: Daniel Baluta > Cc: Jonathan Cameron > Signed-off-by: Akinobu Mita Applied to the fixes-togreg branch of iio.git and marked for stable. The only minor thing that you could have done to make this series even better would be to have figured out appropriate Fixes: tags to make the job of the stable maintainers a little easier. Mostly I think it is a case of 'if it will apply then it should' here though so I haven't dug into it enough to tag them all. Thanks, Jonathan > --- > drivers/iio/adc/ti-ads1015.c | 27 ++++++++++----------------- > 1 file changed, 10 insertions(+), 17 deletions(-) > > diff --git a/drivers/iio/adc/ti-ads1015.c b/drivers/iio/adc/ti-ads1015.c > index 884b8e46..443444c 100644 > --- a/drivers/iio/adc/ti-ads1015.c > +++ b/drivers/iio/adc/ti-ads1015.c > @@ -252,9 +252,11 @@ int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val) > > ret = regmap_update_bits_check(data->regmap, ADS1015_CFG_REG, > ADS1015_CFG_MUX_MASK | > - ADS1015_CFG_PGA_MASK, > + ADS1015_CFG_PGA_MASK | > + ADS1015_CFG_DR_MASK, > chan << ADS1015_CFG_MUX_SHIFT | > - pga << ADS1015_CFG_PGA_SHIFT, > + pga << ADS1015_CFG_PGA_SHIFT | > + dr << ADS1015_CFG_DR_SHIFT, > &change); > if (ret < 0) > return ret; > @@ -325,25 +327,16 @@ static int ads1015_set_scale(struct ads1015_data *data, int chan, > > static int ads1015_set_data_rate(struct ads1015_data *data, int chan, int rate) > { > - int i, ret, rindex = -1; > + int i; > > - for (i = 0; i < ARRAY_SIZE(ads1015_data_rate); i++) > + for (i = 0; i < ARRAY_SIZE(ads1015_data_rate); i++) { > if (data->data_rate[i] == rate) { > - rindex = i; > - break; > + data->channel_data[chan].data_rate = i; > + return 0; > } > - if (rindex < 0) > - return -EINVAL; > - > - ret = regmap_update_bits(data->regmap, ADS1015_CFG_REG, > - ADS1015_CFG_DR_MASK, > - rindex << ADS1015_CFG_DR_SHIFT); > - if (ret < 0) > - return ret; > - > - data->channel_data[chan].data_rate = rindex; > + } > > - return 0; > + return -EINVAL; > } > > static int ads1015_read_raw(struct iio_dev *indio_dev,