From patchwork Tue Jan 12 04:09:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gwendal Grignou X-Patchwork-Id: 12012331 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 93A55C433E0 for ; Tue, 12 Jan 2021 04:10:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4333022CF6 for ; Tue, 12 Jan 2021 04:10:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727939AbhALEKH (ORCPT ); Mon, 11 Jan 2021 23:10:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44854 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726564AbhALEKH (ORCPT ); Mon, 11 Jan 2021 23:10:07 -0500 Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3824AC061575 for ; Mon, 11 Jan 2021 20:09:27 -0800 (PST) Received: by mail-pl1-x62e.google.com with SMTP id q4so689237plr.7 for ; Mon, 11 Jan 2021 20:09:27 -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=vyL9AEMjH5LWqpHoqXCBrwI8PaVFckxwxaCMSAC7ThY=; b=ZOf/vTcBl4KnJAcvvkHbLm87f22xj3oc+1RlAU80+//EA0fNeYcuh4WqHsT1eRYWUa eansoucBd08fvt5pk1cFlHgVMO20hvgxaiSMxqu8RH+fUpdmtQn4JWi6PCHVv75JLhLz CV1ShnHQyWWtGhaDRE66jzAS9QrWtcMDC2wnc= 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=vyL9AEMjH5LWqpHoqXCBrwI8PaVFckxwxaCMSAC7ThY=; b=StTz71I4R54GAPLo+0BxsR/BDCPmCRofCpFBTxaUoDUvBv4NNp3OLETS5Vrc/oSPLp VUMgWzQ6PcgRr4kJOakEyacAJWA4YPGqjWsQkreoOv9AOAYHqrdt5rPeCDROdCVMQn5t oKY9kOT71TXWRV9FaVq6PxQjCpJV6f8e7dX6XgD4mRgFLP/xIcUhN/2Pz6r4lfkCTtL0 qhz0xm0XL+Sq2Xotv52SsStXLsiQkInbKTMHbijiOCzqJSmS/6r0pXJ4tbvG40iffc52 x11k48PxE39ObORgwKCpyDs86kjVVurb0HEGgy++z1MZSRDTtloYL00wheIEtOfj145m +tCw== X-Gm-Message-State: AOAM531A93DNNh8tyVcR2MYw2/7uAgiSIWhrTx489CjXQ2xg3LLm9OiM ZWIX0GSvJxu8pt0R1xvfc7rT6w== X-Google-Smtp-Source: ABdhPJzFIqP2LNKixi3P/0AMIPo39l8CBKwVDcd7BYFwzXD7RI/0jA5Dwi7+LU8mWMVzYHBkvGSjww== X-Received: by 2002:a17:902:a5cb:b029:dc:2706:4cc8 with SMTP id t11-20020a170902a5cbb02900dc27064cc8mr2765230plq.62.1610424566735; Mon, 11 Jan 2021 20:09:26 -0800 (PST) Received: from localhost ([2620:15c:202:201:7220:84ff:fe09:94fe]) by smtp.gmail.com with ESMTPSA id h10sm1120880pfn.213.2021.01.11.20.09.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 Jan 2021 20:09:26 -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 v5] iio: hrtimer: Allow sub Hz granularity Date: Mon, 11 Jan 2021 20:09:23 -0800 Message-Id: <20210112040923.2613711-1-gwendal@chromium.org> X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-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 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 | 26 ++++++++++++++++---------- 2 files changed, 17 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..1effab04e00a8 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 +50,22 @@ 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; + 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 > NSEC_PER_SEC * 1000) return -EINVAL; - info->sampling_frequency = val; - info->period = NSEC_PER_SEC / val; + info->sampling_frequency[0] = integer; + info->sampling_frequency[1] = fract * 1000; + info->period = NSEC_PER_SEC * 1000; + do_div(info->period, val); return len; } @@ -135,8 +141,8 @@ 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)