From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net ([212.227.15.15]:53453 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750819AbbHVVyo (ORCPT ); Sat, 22 Aug 2015 17:54:44 -0400 Message-ID: <55D8EF99.5080305@gmx.de> Date: Sat, 22 Aug 2015 23:54:33 +0200 From: Hartmut Knaack MIME-Version: 1.0 To: Nicola Corna , Jonathan Cameron , Lars-Peter Clausen , Peter Meerwald CC: linux-iio@vger.kernel.org Subject: Re: [PATCH v2 1/2] iio:humidity:si7020: replaced bitmask on humidity values with range check References: <1440266488-21507-1-git-send-email-nicola@corna.info> <55D8ED25.4040409@gmx.de> In-Reply-To: <55D8ED25.4040409@gmx.de> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org Hartmut Knaack schrieb am 22.08.2015 um 23:44: > Nicola Corna schrieb am 22.08.2015 um 20:01: >> The maximum possible value for the relative humidity is 55575 (100%RH). >> This value, if shifted right by 2 bits, uses 14 bits and masking it with >> a 12 bit mask removes 2 meaningful bits. >> The masking has been replaced with a range check that sets the minimum >> value at 786 (0%RH) and the maximum at 13894 (100%RH). >> >> Signed-off-by: Nicola Corna > > Might be discussable, if we want the upper boundary to be rounded down, > so we just barely reach 100% rather than slightly exceeding it (in numbers, > that is 99,998 vs 100,006). Using 13893 might be the better value. Other > than that (and a typo in the comment) looking good, so: > Reviewed-by: Hartmut Knaack On second thought, this is not exactly how clamp_val works. It will return a value between the boundaries, so usage is like this: *val = clamp_val(*val, 786, 13894) If my suggestions are addressed, you can keep my Reviewed-by tag. Thanks, Hartmut >> --- >> drivers/iio/humidity/si7020.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/iio/humidity/si7020.c b/drivers/iio/humidity/si7020.c >> index fa3b809..d27e2f2 100644 >> --- a/drivers/iio/humidity/si7020.c >> +++ b/drivers/iio/humidity/si7020.c >> @@ -57,8 +57,12 @@ static int si7020_read_raw(struct iio_dev *indio_dev, >> if (ret < 0) >> return ret; >> *val = ret >> 2; >> + /* >> + * Humidity values can sligthly exceed the 0-100%RH > > Typo: slightly > >> + * range and should be corrected by software >> + */ >> if (chan->type == IIO_HUMIDITYRELATIVE) >> - *val &= GENMASK(11, 0); >> + clamp_val(*val, 786, 13894); >> return IIO_VAL_INT; >> case IIO_CHAN_INFO_SCALE: >> if (chan->type == IIO_TEMP) >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >