From patchwork Fri Jan 15 23:16:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gwendal Grignou X-Patchwork-Id: 12024383 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=-19.0 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, 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 CED95C433DB for ; Fri, 15 Jan 2021 23:17:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A63AB23382 for ; Fri, 15 Jan 2021 23:17:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726162AbhAOXRJ (ORCPT ); Fri, 15 Jan 2021 18:17:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725863AbhAOXRI (ORCPT ); Fri, 15 Jan 2021 18:17:08 -0500 Received: from mail-pg1-x531.google.com (mail-pg1-x531.google.com [IPv6:2607:f8b0:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 605F6C0613D3 for ; Fri, 15 Jan 2021 15:16:28 -0800 (PST) Received: by mail-pg1-x531.google.com with SMTP id g15so6965976pgu.9 for ; Fri, 15 Jan 2021 15:16:28 -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=uSop28QKfbgeQS619poHgerSZ2oNr0NFuecw4kYHheU=; b=DUUR6mCOr8Voy04tI7XTnNK6SVyHdLElGmoxsezmPgliQ9nVeEs9c0RmKGcti+KnWq nXiWPPgJf0nNT1vhFuOGkt/dEx5zb4BGCgjUc4s+Qx97obddQzFh2lDAbqo+FeeIhmfC EejlMmha1hoSjr0oEUPIMHSvcREUXzzmyGbOw= 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=uSop28QKfbgeQS619poHgerSZ2oNr0NFuecw4kYHheU=; b=cwlJFMdyuavQqEQvI5lOLoNxJlS+McIxD1g7RGS73j0eoZ31ONgqgVi8RhhNVYjuNc RtYZ+PQPSqSX3xKLEYVN1kh1X9kb3xBRFrD+ZmX9HzdrbA/UcR9mS4kEOfN74542dEHN 419EXsMfDb1KmhCBoKljumoKr08BqPXS4JMevdbjLGaIFQQawy4jQ87bDDrx5WBBJf8o 1OXBnRJ1A5aDKq2ZUswAnepppCjiCSC25dL2pIk19qEhY+zw/GeCQB3rVhmMvnWydcnF M4SV6hlcqcx7IlD/D0s83db5CnVFIqeCinC5Xdtoa/WHL8FG4SWR/qAu2IGgp7iFOE7x MECw== X-Gm-Message-State: AOAM533a8782a93II7oDU3OO+/vQgmQJEFT4Ew+n1gjuN6w+bPDyhWvL 7PBvn5ZoCzv9QdRnIuedhphQhw== X-Google-Smtp-Source: ABdhPJxMjgFYWTmJnjy9y6+S+fsKH0XHGnaYfD5709x0CMRi3UGcAWrsrfsq8bCnaG2otTScRtpMeQ== X-Received: by 2002:aa7:9eda:0:b029:19d:ce86:f941 with SMTP id r26-20020aa79eda0000b029019dce86f941mr14830777pfq.57.1610752587775; Fri, 15 Jan 2021 15:16:27 -0800 (PST) Received: from localhost ([2620:15c:202:201:7220:84ff:fe09:94fe]) by smtp.gmail.com with ESMTPSA id o1sm8813965pgq.1.2021.01.15.15.16.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 15 Jan 2021 15:16:26 -0800 (PST) From: Gwendal Grignou To: jic23@kernel.org, lars@metafoo.de, andy.shevchenko@gmail.com Cc: linux-iio@vger.kernel.org, Gwendal Grignou Subject: [PATCH v6] iio: hrtimer: Allow sub Hz granularity Date: Fri, 15 Jan 2021 15:16:13 -0800 Message-Id: <20210115231613.2878027-1-gwendal@chromium.org> X-Mailer: git-send-email 2.30.0.296.g2bfb1c46d8-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 --- 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 | 28 +++++++++++++++++--------- 2 files changed, 19 insertions(+), 10 deletions(-) diff --git a/Documentation/iio/iio_configfs.rst b/Documentation/iio/iio_configfs.rst index ecbfdb3afef7e..807589ef2bea0 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 58c1c30d5612b..b560194b4f1f3 100644 --- a/drivers/iio/trigger/iio-trig-hrtimer.c +++ b/drivers/iio/trigger/iio-trig-hrtimer.c @@ -22,7 +22,7 @@ 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 +38,9 @@ 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 +50,24 @@ 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 (!val || val > NSEC_PER_SEC) + val = fract + 1000 * integer; + + if (!val || val > UINT_MAX) return -EINVAL; - info->sampling_frequency = val; - info->period = NSEC_PER_SEC / val; + info->sampling_frequency[0] = integer; + info->sampling_frequency[1] = fract * 1000; + period = PSEC_PER_SEC; + do_div(period, val); + info->period = period; return len; } @@ -135,8 +143,8 @@ 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)