From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from saturn.retrosnub.co.uk ([178.18.118.26]:36612 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755637AbbI0N3z (ORCPT ); Sun, 27 Sep 2015 09:29:55 -0400 Subject: Re: [PATCH] iio: hdc100x: correct IIO_CHAN_INFO_OFFSET value To: Matt Ranostay References: <1443334737-3772-1-git-send-email-mranostay@gmail.com> Cc: linux-iio@vger.kernel.org From: Jonathan Cameron Message-ID: <5607EF50.6020102@kernel.org> Date: Sun, 27 Sep 2015 14:29:52 +0100 MIME-Version: 1.0 In-Reply-To: <1443334737-3772-1-git-send-email-mranostay@gmail.com> Content-Type: text/plain; charset=windows-1252 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 27/09/15 07:18, Matt Ranostay wrote: > Previous offset wasn't applied in the correct order and invalid. > This patchset fixes this issue, and also has the correct scale value > applied to the offset. > > Signed-off-by: Matt Ranostay Oops, missed that. Given it's provided in the datasheet as effectively a fractional value would val = -40000, val2 = 65536 and type = IIO_FRACTIONAL not be cleaner and give the same answer? Speaking of which, for the scale are we loosing any precision by shifting the bottom of the fraction right 2 rather than the top left 2 which would have the same result? Jonathan > --- > drivers/iio/humidity/hdc100x.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c > index 2824578..a7f61e8 100644 > --- a/drivers/iio/humidity/hdc100x.c > +++ b/drivers/iio/humidity/hdc100x.c > @@ -221,8 +221,9 @@ static int hdc100x_read_raw(struct iio_dev *indio_dev, > } > break; > case IIO_CHAN_INFO_OFFSET: > - *val = -40; > - return IIO_VAL_INT; > + *val = -3971; > + *val2 = 879096; > + return IIO_VAL_INT_PLUS_MICRO; > default: > return -EINVAL; > } >