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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED autolearn=ham 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 B5810C282E1 for ; Sat, 25 May 2019 00:28:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84135217F9 for ; Sat, 25 May 2019 00:28:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="FR+11UmK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726220AbfEYA2y (ORCPT ); Fri, 24 May 2019 20:28:54 -0400 Received: from mail-it1-f194.google.com ([209.85.166.194]:40785 "EHLO mail-it1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726166AbfEYA2x (ORCPT ); Fri, 24 May 2019 20:28:53 -0400 Received: by mail-it1-f194.google.com with SMTP id h11so16258531itf.5 for ; Fri, 24 May 2019 17:28:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QJl2y/2VeXoRp5nqdS1Giklh1RcU9ZirEcrKjJT5+I0=; b=FR+11UmKdJ3V3Ee8HFOSIFSoJrx8FkKmvNI+1FbfAKZq/87wn6C3HN/6cOAOovg787 Yw5WbnxtX0gwQmR0x23LqFvFkEUGnALzSU5CG/lF6LYABvF5vkNLPIl56c0EOvCsOQYN Q5nv+HRncndknW7IKVQU9lAeqWnLVcY1/A49g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=QJl2y/2VeXoRp5nqdS1Giklh1RcU9ZirEcrKjJT5+I0=; b=eus8j7cJGpCmRj+cUXeOJd0L+CaMPTL69Je6v06B3ITDgnM4qRZG+g31rg2LyxGNjz SKEm3Z8s96ske6d4iP0RwnnzxtIvp6u6Ihs4jax1EdK6FarhxakyOdZDuQ9cXQDdryup PAKdCi9HyKD/MdzibjE1fkm89jPkV/mcl+InlVHf+j/M4hxNLcCWb6TLhWXxt3tVaQrR ew7si3n5TioXOZnQn1q1YSV8CvKKsUGP24JClrvvr04UHvJHUJ6ksiWfZmlKymA+MwOv Gx1Y9hoxDu74EIxAcOzkSBitQKGpkVqZWMFWmq09p4pbgGAqpg1mL1W6i6lxs8/2ELHP mhAw== X-Gm-Message-State: APjAAAV54gtPVFtQsmKvPpUYZ4DgA8OxvGIgav2qEeVTBx8Y36CaT+Nw MUWI/P/+dcR284FGhDnTgSL2xS48ghvrgryOvdYwH1zRvc1MBg== X-Google-Smtp-Source: APXvYqyiDDv0VSrCW6eUY79D0aOtxfZAhDwdUn8lyr3b+k5NhLU5h4nmNUyYvzihAihNtw1cviOr4IQbiBTrIpYXxI4= X-Received: by 2002:a24:1185:: with SMTP id 127mr18846962itf.106.1558744132968; Fri, 24 May 2019 17:28:52 -0700 (PDT) MIME-Version: 1.0 References: <20190505163647.4f961a0d@archlinux> In-Reply-To: <20190505163647.4f961a0d@archlinux> From: Gwendal Grignou Date: Fri, 24 May 2019 17:28:42 -0700 Message-ID: Subject: Re: [RFC 1/1] iio: common: cros_ec_sensors: add extra sensor API To: Jonathan Cameron Cc: Fabien Lahoudere , linux-iio@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Sun, May 5, 2019 at 8:36 AM Jonathan Cameron wrote: > > On Fri, 3 May 2019 12:54:46 +0200 > Fabien Lahoudere wrote: > > > From: Gwendal Grignou > > > > Version 3 of the EC protocol provides min and max frequencies and fifo > > size for EC sensors. > > The driver allows EC to set parameters for version 3 and set default values > > for earlier versions. > > The sysfs entries are read only and cannot be used to impact on values. > > > > Signed-off-by: Gwendal Grignou > > Signed-off-by: Fabien Lahoudere > Mostly changes in here will follow from comments on the cover letter > but a few other things inline. > > Thanks, > > Jonathan > > --- > > .../ABI/testing/sysfs-bus-iio-cros-ec | 24 ++++ > > .../cros_ec_sensors/cros_ec_sensors_core.c | 126 +++++++++++++++++- > > .../linux/iio/common/cros_ec_sensors_core.h | 7 + > > include/linux/mfd/cros_ec_commands.h | 21 +++ > > 4 files changed, 177 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-cros-ec b/Documentation/ABI/testing/sysfs-bus-iio-cros-ec > > index 0e95c2ca105c..85d266f4a57e 100644 > > --- a/Documentation/ABI/testing/sysfs-bus-iio-cros-ec > > +++ b/Documentation/ABI/testing/sysfs-bus-iio-cros-ec > > @@ -26,3 +26,27 @@ Description: > > driver and represents the sensor ID as exposed by the EC. This > > ID is used by the Android sensor service hardware abstraction > > layer (sensor HAL) through the Android container on ChromeOS. > > + > > +What: /sys/bus/iio/devices/iio:deviceX/min_frequency > > +Date: April 2019 > > +KernelVersion: 5.0 > > +Contact: linux-iio@vger.kernel.org > > +Description: > > + This attribute is exposed by CrOS EC sensors. It defines the > > + minimum frequency used by the sensor. > > + > > +What: /sys/bus/iio/devices/iio:deviceX/max_frequency > > +Date: April 2019 > > +KernelVersion: 5.0 > > +Contact: linux-iio@vger.kernel.org > > +Description: > > + This attribute is exposed by CrOS EC sensors. It defines the > > + maximum frequency used by the sensor. > > + > See reply to the cover letter on these. Bonus points if you implement them > with the read_avail callback. > > > +What: /sys/bus/iio/devices/iio:deviceX/max_events > > +Date: April 2019 > > +KernelVersion: 5.0 > > +Contact: linux-iio@vger.kernel.org > > +Description: > > + This attribute is exposed by CrOS EC sensors. It defines the > > + maximum number of events in the fifo. > > Why does userspace care? Is use to report the size of the hardware FIFO to Android, to enable batching mode: https://source.android.com/devices/sensors/batching. It is reported in fifoReservedEventCount or fifoMaxEventCount in the sensor_t structure described at https://source.android.com/devices/sensors/hal-interface#sensor_t. Having said that, batching is not terribly useful for tablet or laptop, but is critical for wearable.