From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79215C0650F for ; Mon, 5 Aug 2019 13:44:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 496CD20880 for ; Mon, 5 Aug 2019 13:44:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565012690; bh=y4WpUC9q34H82VZ0dcYCM8MoJKvxUAW1HgdUrVm32JQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=ycfNg2gFsrkRg6rnhuLnCaGFkL3DJw4BRtOoDGBIyl6sA3VuH5psYZp3jJdjPgjIc Gf4NW1CfkmeN/0S/PljpmYmZDXSaC42uaKhIuBo5VhdzghkLh/XONp2pdb5wnxolrj 7sRc4C4xpLW+mIt1bLhnVRHg411oGni+I69JXC54= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731114AbfHENoo (ORCPT ); Mon, 5 Aug 2019 09:44:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:41596 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731112AbfHENoo (ORCPT ); Mon, 5 Aug 2019 09:44:44 -0400 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 177142087B; Mon, 5 Aug 2019 13:44:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565012683; bh=y4WpUC9q34H82VZ0dcYCM8MoJKvxUAW1HgdUrVm32JQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=MfqclNGZF3xBa0FIKSpVGVyIJW3Vs0e/hJx4mB4hDyIoE12SMOPuSHBAqGV3HvIVS 4Zjs01jnTLGIFWswz9rEBy0yJ0I3qn4lcNP1Q9IJyHq2UNPbXc9JNti6YNoZr+hR17 K/UXLg1GFGG0dDnvfmV/vui2xcd+uaxmH0sVZlzc= Date: Mon, 5 Aug 2019 14:44:38 +0100 From: Jonathan Cameron To: Lorenzo Bianconi Cc: Martin Kepplinger , lorenzo.bianconi83@gmail.com, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 4/5] iio: imu: st_lsm6dsx: add support for accel/gyro unit of lsm9sd1 Message-ID: <20190805144438.133867b2@archlinux> In-Reply-To: <20190728175234.GA7652@lore-desk-wlan.lan> References: <20190725053132.9589-1-martin.kepplinger@puri.sm> <20190725053132.9589-5-martin.kepplinger@puri.sm> <20190727184844.307255a2@archlinux> <20190728093414.5d3ca94d@archlinux> <20190728175234.GA7652@lore-desk-wlan.lan> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Sun, 28 Jul 2019 19:52:34 +0200 Lorenzo Bianconi wrote: > > On Sun, 28 Jul 2019 08:04:51 +0200 > > Martin Kepplinger wrote: > > > > > On 27.07.19 19:48, Jonathan Cameron wrote: > > > > On Thu, 25 Jul 2019 07:31:31 +0200 > > > > Martin Kepplinger wrote: > > > > > > > >> The LSM9DS1's accelerometer / gyroscope unit and it's magnetometer (separately > > > >> supported in iio/magnetometer/st_magn*) are located on a separate i2c addresses > > > >> on the bus. > > > >> > > > >> For the datasheet, see https://www.st.com/resource/en/datasheet/lsm9ds1.pdf > > > >> > > > >> Treat it just like the LSM6* devices and, despite it's name, hook it up > > > >> to the st_lsm6dsx driver, using it's basic functionality. > > > >> > > > >> Signed-off-by: Martin Kepplinger > > > > I'm a little confused on this hardware. > > > > > > > > How does buffered output work if these are independently clocked? > > > > > > > > I took a quick look at the datasheet, and 'suspect' the answer is that > > > > it runs at the gyro frequencies if both are enable. Is that right? > > > > > > > > > > Thanks for reviewing, Jonathan, > > > > > > Correct. It says so in chapter 7.12. But that's a "problem" with all > > > these imu devices, not specific to this addition right? > > It's not a problem as such, but there is a related difference in this > > device to the others supported by this driver. > > > > The other parts seem to allow for independent data rate setting, with > > streaming to the buffer that isn't in 'lock step'. I.e you can get > > > > Ax_1, Ay_1, Az_1, Gx_1, Gy_1, Gz_1, Gx_2, Gy_2, Gz_2, Ax_2, Ay_2, Az_2, Gy_3... > > correct > > > > > That required us to split them up into two devices and means that, to fuse > > data from these two source, userspace has to do the harder job of > > aligning the two datasets. > > > > For this device, things are simpler in that you always a 'scan' that goes > > across both accelerometer and gyroscope channels. That allows us to > > represent it as a single IIO device with a single buffer. > > > > I'm not seeing any reference in the lsm9ds1 to the pattern registers > > that are used to handle difference in frequency for the other > > parts by letting us know what is actually present in each data set > > in the fifo. > > > > Now, that doesn't meant we can't still handle them separately given > > we already do that for other parts. > > what about reusing st_lsm6dsx_read_fifo() for lsm6ds0/lsm9ds1 but setting hw->sip to: > - hw->sip = 1 (acc_sip = 1, gyro_sip = 0) when just the acc is enabled > - hw->sip = 2 (acc_sip = 1, gyro_sip = 1) when both devices are enabled > > I guess it is just a matter of adding a 'bool fixed_pattern' in > st_lsm6dsx_settings. What do you think? If I understand this, the intent is still to split it to two separate IIO devices? I don't really mind if that's the case and it seems like something similar to what you describe should work for that. If we go this way, some comments should be added to explain that whilst we could have handled this as a single IIO device, we have split it to be more consistent with the other more flexible devices. Thanks, Jonathan > > Regards, > Lorenzo > > > > > Anyhow, is my understanding correct? > > > > Jonathan > > > > > > > > Sidenote: I thought about renaming things to "lsm6ds0" here just because > > > of the name and because the registers are (almost) the same as for my > > > lsm9ds1. But I'm not a fan of blindly doing that without being able to > > > test. When the current patchset looks good to you, let's keep it that way. > > > > > > martin > >