From patchwork Fri Feb 26 01:47:33 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gwendal Grignou X-Patchwork-Id: 12105607 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 8BFA2C433E0 for ; Fri, 26 Feb 2021 01:48:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 405FC64E4D for ; Fri, 26 Feb 2021 01:48:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229508AbhBZBsV (ORCPT ); Thu, 25 Feb 2021 20:48:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229492AbhBZBsV (ORCPT ); Thu, 25 Feb 2021 20:48:21 -0500 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0400EC061574 for ; Thu, 25 Feb 2021 17:47:40 -0800 (PST) Received: by mail-pj1-x1035.google.com with SMTP id e9so5162232pjj.0 for ; Thu, 25 Feb 2021 17:47:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=uIcD1B1LxoaKsY+eEVtZxACUjmvKqFVGILl0I8NPioY=; b=nYTxe1s99y9kSsg7kQ8zOZEEmHbfNwsbe/NLgLp0t6X5UiSFiHy945RArMCQUxu2KJ het+YPPrsLB9bCYS/RiosfH81I/bD3CNhWgeY94XG7JLSUNzrx9bHWJYaIRcF+TbnKlj gBZ43eCNKE2L7sBHUns0g7y3brRWRz6ANwt34= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=uIcD1B1LxoaKsY+eEVtZxACUjmvKqFVGILl0I8NPioY=; b=OwNcDATXi7Fm8N4uI19cHsA1pjr3RWgGGu8qW/nXpSFf1evVEdYpaOvjczh71F9xNn 1WRL/Km0blVclANSBTf9KzBDdkpprhgOhKjEgVQCQuP6kJIoFLuiBuXbh4Jz9iuJTSK1 7b3Ea40YKB1LGYufYu727NIm9RWN3b4aAM8+gWLany8+hZGOso8VUDcE3BFYrfgqmjGF S1t9gXpW2BXtEHODmU6jMXv9cRjzcV98CmUfPoZE9Ky2fqliWWTP49+0jt4oKtVPreGO yP0qmAcBNscZ5hQVEPQ3mz28p9yZio0xXwU6wzs05upi6s6WqHZd61mXqNb8xSXBB19Z KQnQ== X-Gm-Message-State: AOAM530aa1tNUn8zISrlI1ZbNCxBrTzs01xkAPXBR1HTNfJRjLoAC6et VymPAqi8igFjdqS73c960QJPAA== X-Google-Smtp-Source: ABdhPJy0XhSakYhXjoiWMzrZaaaTpTj0loSqQ4odW5ktpLpVF7YN+u8P8Tai8zu7VIwrkoce4wkVag== X-Received: by 2002:a17:90a:e603:: with SMTP id j3mr820614pjy.161.1614304060359; Thu, 25 Feb 2021 17:47:40 -0800 (PST) Received: from localhost ([2620:15c:202:201:b0a4:446e:a265:bffe]) by smtp.gmail.com with UTF8SMTPSA id d124sm7394503pfa.149.2021.02.25.17.47.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 25 Feb 2021 17:47:39 -0800 (PST) From: Gwendal Grignou To: jic23@kernel.org, lars@metafoo.de, andy.shevchenko@gmail.com, groeck@chromium.org Cc: linux-iio@vger.kernel.org, Gwendal Grignou Subject: [PATCH v9] iio: hrtimer: Allow sub Hz granularity Date: Thu, 25 Feb 2021 17:47:33 -0800 Message-Id: <20210226014733.2108544-1-gwendal@chromium.org> X-Mailer: git-send-email 2.30.1.766.gb4fecdf3b7-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org 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 Reviewed-by: Andy Shevchenko --- 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 | 33 ++++++++++++++++++-------- 2 files changed, 24 insertions(+), 10 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..aa8cc7391a60d 100644 --- a/drivers/iio/trigger/iio-trig-hrtimer.c +++ b/drivers/iio/trigger/iio-trig-hrtimer.c @@ -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)