From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.19.201]:37344 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752620AbaGLMRc (ORCPT ); Sat, 12 Jul 2014 08:17:32 -0400 Message-ID: <53C127E1.2090801@kernel.org> Date: Sat, 12 Jul 2014 13:19:45 +0100 From: Jonathan Cameron MIME-Version: 1.0 To: Hartmut Knaack , Martin Fuzzey , linux-iio@vger.kernel.org Subject: Re: [PATCH] iio: mma8452: Use correct acceleration units. References: <20140711125431.22109.59659.stgit@localhost> <53C11313.20803@gmx.de> In-Reply-To: <53C11313.20803@gmx.de> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 12/07/14 11:50, Hartmut Knaack wrote: > Martin Fuzzey schrieb: >> The userspace interface for acceleration sensors is documented as using >> m/s^2 units [Documentation/ABI/testing/sysfs-bus-iio] >> >> The fullscale raw value for the mma8452 (-2048) corresponds to -2G, -4G or -8G >> depending on the seleted mode. >> >> The scale table was converting to G rather than m/s^2. >> Change the scaling table to match the documented interface. >> >> Signed-off-by: Martin Fuzzey Fixed up and applied to the fixes-togreg branch of iio.git. Also marked for stable. Thanks, J >> --- >> drivers/iio/accel/mma8452.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c >> index 17aeea1..61eba5a 100644 >> --- a/drivers/iio/accel/mma8452.c >> +++ b/drivers/iio/accel/mma8452.c >> @@ -111,8 +111,13 @@ static const int mma8452_samp_freq[8][2] = { >> {6, 250000}, {1, 560000} >> }; >> > The first line of the comment should just contain /* >> +/* Hardware has fullscale of -2G, -4G, -8G corresponding to raw value -2048 >> + * The userspace interface uses m/s^2 and we declare micro units >> + * So scale factor is given by: >> + * g * N * 1000000 / 2048 for N = 2, 4, 8 and g=9.80665 >> + */ >> static const int mma8452_scales[3][2] = { >> - {0, 977}, {0, 1953}, {0, 3906} >> + {0, 9577}, {0, 19154}, {0, 38307} >> }; >> >> static ssize_t mma8452_show_samp_freq_avail(struct device *dev, >> >> -- >> 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 >> >