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=-15.5 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 B3102C433DB for ; Sat, 13 Mar 2021 17:17:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 82DFD64E5F for ; Sat, 13 Mar 2021 17:17:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234103AbhCMRQj (ORCPT ); Sat, 13 Mar 2021 12:16:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:60210 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234134AbhCMRQ1 (ORCPT ); Sat, 13 Mar 2021 12:16:27 -0500 Received: from archlinux (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (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 A519F64F16; Sat, 13 Mar 2021 17:16:26 +0000 (UTC) Date: Sat, 13 Mar 2021 17:16:23 +0000 From: Jonathan Cameron To: Gwendal Grignou Cc: lars@metafoo.de, andy.shevchenko@gmail.com, groeck@chromium.org, linux-iio@vger.kernel.org Subject: Re: [PATCH v10] iio: hrtimer: Allow sub Hz granularity Message-ID: <20210313171623.0ba39237@archlinux> In-Reply-To: <20210309213039.2188888-1-gwendal@chromium.org> References: <20210309213039.2188888-1-gwendal@chromium.org> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Tue, 9 Mar 2021 13:30:39 -0800 Gwendal Grignou wrote: > Allow setting frequency below 1Hz or sub 1Hz precision. > Useful for slow sensors like ALS. > > Test frequency is set properly: > modprobe iio-trig-hrtimer && \ > mkdir /sys/kernel/config/iio/triggers/hrtimer/t1 && \ > cd /sys/bus/iio/devices/triggerX ; > for i in 1 .1 .01 .001 ; do > echo $i > sampling_frequency > cat sampling_frequency > done > > Signed-off-by: Gwendal Grignou I'd already picked up v9. Your follow up fixup patch dealt with the accidental kerneldoc. So I think everything is good now. Thanks, Jonathan > --- > Changes since v9: > - Remove kernel-doc mark in file header comment to fix a kernel test > robot warning: > "warning: expecting prototype for O periodic hrtimer trigger driver(). > Prototype was for PSEC_PER_SEC() instead" > > Changes since v8: > - Define PSEC_PER_SEC locally to avoid dependency > - Add units of expressions in comment. > > Changes since v7: > - Check for sign properly, only allow positive frequencies. > - Return proper error code when input frequency is negative. > > Changes since v6: > - Check for sign, only allow positive frequencies. > > Changes since v5: > - Properly support do_div on 32bit architecture: quotient must be u64, dividend > u32. > - Use PSEC_PER_SEC from > https://patchwork.kernel.org/project/linux-iio/patch/20210112153709.1074-1-andriy.shevchenko@linux.intel.com/ > > Changes since v4: > - Use do_div() properly. > > Changes since v3: > - Fix rebasing issue. > > Changes since v2: > - Add do_div to allow divide by a u64 on 32bit machines. > > Changes since v1: > - Added documentation. > > Documentation/iio/iio_configfs.rst | 1 + > drivers/iio/trigger/iio-trig-hrtimer.c | 35 ++++++++++++++++++-------- > 2 files changed, 25 insertions(+), 11 deletions(-) > > diff --git a/Documentation/iio/iio_configfs.rst b/Documentation/iio/iio_configfs.rst > index 3a5d76f9e2b97..09845fe525e84 100644 > --- a/Documentation/iio/iio_configfs.rst > +++ b/Documentation/iio/iio_configfs.rst > @@ -99,3 +99,4 @@ Each trigger can have one or more attributes specific to the trigger type. > > "hrtimer" trigger type doesn't have any configurable attribute from /config dir. > It does introduce the sampling_frequency attribute to trigger directory. > +That attribute sets the polling frequency in Hz, with mHz precision. > diff --git a/drivers/iio/trigger/iio-trig-hrtimer.c b/drivers/iio/trigger/iio-trig-hrtimer.c > index 410de837d0417..e68a2c56d4593 100644 > --- a/drivers/iio/trigger/iio-trig-hrtimer.c > +++ b/drivers/iio/trigger/iio-trig-hrtimer.c > @@ -1,5 +1,5 @@ > // SPDX-License-Identifier: GPL-2.0-only > -/** > +/* > * The industrial I/O periodic hrtimer trigger driver > * > * Copyright (C) Intuitive Aerial AB > @@ -16,13 +16,16 @@ > #include > #include > > +/* Defined locally, not in time64.h yet. */ > +#define PSEC_PER_SEC 1000000000000LL > + > /* default sampling frequency - 100Hz */ > #define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 100 > > struct iio_hrtimer_info { > struct iio_sw_trigger swt; > struct hrtimer timer; > - unsigned long sampling_frequency; > + int sampling_frequency[2]; > ktime_t period; > }; > > @@ -38,7 +41,9 @@ ssize_t iio_hrtimer_show_sampling_frequency(struct device *dev, > struct iio_trigger *trig = to_iio_trigger(dev); > struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig); > > - return snprintf(buf, PAGE_SIZE, "%lu\n", info->sampling_frequency); > + return iio_format_value(buf, IIO_VAL_INT_PLUS_MICRO, > + ARRAY_SIZE(info->sampling_frequency), > + info->sampling_frequency); > } > > static > @@ -48,18 +53,26 @@ ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev, > { > struct iio_trigger *trig = to_iio_trigger(dev); > struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig); > - unsigned long val; > - int ret; > + unsigned long long val; > + u64 period; > + int integer, fract, ret; > > - ret = kstrtoul(buf, 10, &val); > + ret = iio_str_to_fixpoint(buf, 100, &integer, &fract); > if (ret) > return ret; > + if (integer < 0 || fract < 0) > + return -ERANGE; > + > + val = fract + 1000 * integer; /* mHz */ > > - if (!val || val > NSEC_PER_SEC) > + if (!val || val > UINT_MAX) > return -EINVAL; > > - info->sampling_frequency = val; > - info->period = NSEC_PER_SEC / val; > + info->sampling_frequency[0] = integer; /* Hz */ > + info->sampling_frequency[1] = fract * 1000; /* uHz */ > + period = PSEC_PER_SEC; > + do_div(period, val); > + info->period = period; /* nS */ > > return len; > } > @@ -135,8 +148,8 @@ static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name) > hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); > trig_info->timer.function = iio_hrtimer_trig_handler; > > - trig_info->sampling_frequency = HRTIMER_DEFAULT_SAMPLING_FREQUENCY; > - trig_info->period = NSEC_PER_SEC / trig_info->sampling_frequency; > + trig_info->sampling_frequency[0] = HRTIMER_DEFAULT_SAMPLING_FREQUENCY; > + trig_info->period = NSEC_PER_SEC / trig_info->sampling_frequency[0]; > > ret = iio_trigger_register(trig_info->swt.trigger); > if (ret)