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=-11.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 4933FC433E2 for ; Wed, 16 Sep 2020 21:07:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3BA8206D4 for ; Wed, 16 Sep 2020 21:07:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=st.com header.i=@st.com header.b="czB7QETT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726472AbgIPVH3 (ORCPT ); Wed, 16 Sep 2020 17:07:29 -0400 Received: from mx07-00178001.pphosted.com ([185.132.182.106]:20452 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726360AbgIPQDk (ORCPT ); Wed, 16 Sep 2020 12:03:40 -0400 Received: from pps.filterd (m0046037.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08GAvX4k010624; Wed, 16 Sep 2020 13:03:08 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=STMicroelectronics; bh=HNBudS2dbgbIeBYY8ROk2CZK0Qs8u5XisjljitaW750=; b=czB7QETTybsqNQT8vRc3WJlJz9uwS1NsPfLhneVlioHCZaRTg+nh64gudZRbf1KrAN1C 379MJyk6AV46Pzv5ybTTM3hZoKzgoMWjNQz8cvt4iLRV0U+UNha/GW6IP7daO8PSNLkW faUbA8bRyBcDjBWboGHOMZ8/7GvVzB2Q+4Ex1Oihxt7byyXETGt6nelsxjgxLJGV3gDL Wu9eQRSjvPMPMLSipZxLP3nq4Trp6dmyruM3U2SRFgLW88LH36kcHMnl0iDyIlVh+AFN +o2FIp83dKTEgz0aUhsBxBHo2Fez6+skDQREczVB0mlMU1yTafxNveBTqkuUbQjJbBpb Uw== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 33k691bg39-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 16 Sep 2020 13:03:08 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 999FE1000AF; Wed, 16 Sep 2020 12:28:01 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag5node3.st.com [10.75.127.15]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 7DE8821CA87; Wed, 16 Sep 2020 12:28:01 +0200 (CEST) Received: from [10.48.1.149] (10.75.127.47) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 16 Sep 2020 12:28:00 +0200 Subject: Re: [RESEND PATCH v2] iio: adc: stm32-adc: fix runtime autosuspend delay when slow polling To: , CC: , , , , , , , , References: <1593615328-5180-1-git-send-email-fabrice.gasnier@st.com> From: Fabrice Gasnier Message-ID: <045e9e34-f1e0-087b-bc5b-44440db6be27@st.com> Date: Wed, 16 Sep 2020 12:28:00 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1593615328-5180-1-git-send-email-fabrice.gasnier@st.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.47] X-ClientProxiedBy: SFHDAG2NODE2.st.com (10.75.127.5) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-16_06:2020-09-16,2020-09-16 signatures=0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/1/20 4:55 PM, Fabrice Gasnier wrote: > When the ADC is runtime suspended and starting a conversion, the stm32-adc > driver calls pm_runtime_get_sync() that gets cascaded to the parent > (e.g. runtime resume of stm32-adc-core driver). This also kicks the > autosuspend delay (e.g. 2s) of the parent. > Once the ADC is active, calling pm_runtime_get_sync() again (upon a new > capture) won't kick the autosuspend delay for the parent (stm32-adc-core > driver) as already active. > > Currently, this makes the stm32-adc-core driver go in suspend state > every 2s when doing slow polling. As an example, doing a capture, e.g. > cat in_voltageY_raw at a 0.2s rate, the auto suspend delay for the parent > isn't refreshed. Once it expires, the parent immediately falls into > runtime suspended state, in between two captures, as soon as the child > driver falls into runtime suspend state: > - e.g. after 2s, + child calls pm_runtime_put_autosuspend() + 100ms > autosuspend delay of the child. > - stm32-adc-core switches off regulators, clocks and so on. > - They get switched on back again 100ms later in this example (at 2.2s). > > So, use runtime_idle() callback in stm32-adc-core driver to call > pm_runtime_mark_last_busy() for the parent driver (stm32-adc-core), > to avoid this. > > Fixes: 9bdbb1139ca1 ("iio: adc: stm32-adc: add power management support") > > Signed-off-by: Fabrice Gasnier > --- > Changes in v2: > - Use runtime_idle callback in stm32-adc-core driver, instead of refreshing > last_busy from the child (for the parent) at many place. Initial patch v1 > looked like "somewhat adhoc solution" as commented by Jonathan. Hi all, Gentle reminder for this patch. Earlier discussions on it were as per [1] and [2]. Ideally, Jonathan was looking for an ack from Rafael on this patch. This is a long pending issue. I'd like to progress on this. [1] https://patchwork.kernel.org/patch/11349841/ [2] https://lkml.org/lkml/2020/6/11/279 Please advise, Thanks in advance, Fabrice > --- > drivers/iio/adc/stm32-adc-core.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c > index 0e2068e..3586369 100644 > --- a/drivers/iio/adc/stm32-adc-core.c > +++ b/drivers/iio/adc/stm32-adc-core.c > @@ -794,6 +794,13 @@ static int stm32_adc_core_runtime_resume(struct device *dev) > { > return stm32_adc_core_hw_start(dev); > } > + > +static int stm32_adc_core_runtime_idle(struct device *dev) > +{ > + pm_runtime_mark_last_busy(dev); > + > + return 0; > +} > #endif > > static const struct dev_pm_ops stm32_adc_core_pm_ops = { > @@ -801,7 +808,7 @@ static const struct dev_pm_ops stm32_adc_core_pm_ops = { > pm_runtime_force_resume) > SET_RUNTIME_PM_OPS(stm32_adc_core_runtime_suspend, > stm32_adc_core_runtime_resume, > - NULL) > + stm32_adc_core_runtime_idle) > }; > > static const struct stm32_adc_priv_cfg stm32f4_adc_priv_cfg = { >