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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 92F47C169C4 for ; Wed, 6 Feb 2019 08:49:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 68EDF2081B for ; Wed, 6 Feb 2019 08:49:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727555AbfBFItD (ORCPT ); Wed, 6 Feb 2019 03:49:03 -0500 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:20386 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727273AbfBFItC (ORCPT ); Wed, 6 Feb 2019 03:49:02 -0500 Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x168f4Qp010305; Wed, 6 Feb 2019 09:48:52 +0100 Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 2qfv9j812q-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT); Wed, 06 Feb 2019 09:48:52 +0100 Received: from zeta.dmz-eu.st.com (zeta.dmz-eu.st.com [164.129.230.9]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 3191F222; Wed, 6 Feb 2019 08:42:37 +0000 (GMT) Received: from Webmail-eu.st.com (sfhdag5node3.st.com [10.75.127.15]) by zeta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 7E19E1697; Wed, 6 Feb 2019 08:42:36 +0000 (GMT) Received: from [10.48.0.167] (10.75.127.46) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Wed, 6 Feb 2019 09:42:35 +0100 Subject: Re: [PATCH 2/4] pwm: stm32-lp: Add power management support To: Tomasz Duszynski CC: , , , , , , , , , , , , References: <1549370429-19116-1-git-send-email-fabrice.gasnier@st.com> <1549370429-19116-3-git-send-email-fabrice.gasnier@st.com> <20190205183005.GA13960@arch> From: Fabrice Gasnier Message-ID: <60d17322-b3b2-943f-779f-33c47412b7a1@st.com> Date: Wed, 6 Feb 2019 09:42:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190205183005.GA13960@arch> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.46] X-ClientProxiedBy: SFHDAG3NODE1.st.com (10.75.127.7) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-06_06:,, signatures=0 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On 2/5/19 7:30 PM, Tomasz Duszynski wrote: > On Tue, Feb 05, 2019 at 01:40:27PM +0100, Fabrice Gasnier wrote: >> Add suspend/resume PM sleep ops. When going to low power, disable >> active PWM channel. Active PWM channel is resumed, by calling >> pwm_apply_state(). This is inspired by Thierry's comment in [1]. >> Don't touch inactive channels, as it may be used by other LPTimer MFD >> child driver. >> [1]https://lkml.org/lkml/2017/12/5/175 >> >> Signed-off-by: Fabrice Gasnier >> --- >> drivers/pwm/pwm-stm32-lp.c | 38 ++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 38 insertions(+) >> >> diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c >> index 0059b24c..0c40d48 100644 >> --- a/drivers/pwm/pwm-stm32-lp.c >> +++ b/drivers/pwm/pwm-stm32-lp.c >> @@ -13,6 +13,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> >> @@ -20,6 +21,8 @@ struct stm32_pwm_lp { >> struct pwm_chip chip; >> struct clk *clk; >> struct regmap *regmap; >> + struct pwm_state suspend; >> + bool suspended; >> }; >> >> static inline struct stm32_pwm_lp *to_stm32_pwm_lp(struct pwm_chip *chip) >> @@ -223,6 +226,40 @@ static int stm32_pwm_lp_remove(struct platform_device *pdev) >> return pwmchip_remove(&priv->chip); >> } >> >> +#ifdef CONFIG_PM_SLEEP > > You might consider dropping ifdefs and marking pm functions with > __maybe_unused instead. In case CONFIG_PM_SLEEP=n then these two guys > will be removed and pm ops structure will be empty. Hi Tomasz, Thanks for this suggestion. I can do this change. I'll wait for more feedback from Uwe and Thierry before sending a v2 with that. > >> +static int stm32_pwm_lp_suspend(struct device *dev) >> +{ >> + struct stm32_pwm_lp *priv = dev_get_drvdata(dev); >> + > > I guess you first need to get platform_device from dev and eventually > stm32_pwm_lp. Wondering how this works now. This should be safe for now. This works because the probe routine calls: platform_set_drvdata(pdev, priv); And the underlying call is dev_set_drvdata() static inline void platform_set_drvdata(struct platform_device *pdev, void *data) { dev_set_drvdata(&pdev->dev, data); } > >> + pwm_get_state(&priv->chip.pwms[0], &priv->suspend); >> + priv->suspended = priv->suspend.enabled; >> + >> + /* safe to call pwm_disable() for already disabled pwm */ >> + pwm_disable(&priv->chip.pwms[0]); >> + >> + return pinctrl_pm_select_sleep_state(dev); >> +} >> + >> +static int stm32_pwm_lp_resume(struct device *dev) >> +{ >> + struct stm32_pwm_lp *priv = dev_get_drvdata(dev); >> + int ret; >> + >> + ret = pinctrl_pm_select_default_state(dev); >> + if (ret) >> + return ret; >> + >> + /* Only restore suspended pwm, not to disrupt other MFD child */ >> + if (!priv->suspended) >> + return 0; > > Would it make sense to use suspend.enabled directly? I propose to keep priv->suspended. Using 'suspend.enabled' directly would simply not work as the pwm_disable() call in stm32_pwm_lp_suspend() routine marks the 'suspend' state.enabled = false. That's why it's saved in the suspend routine, to be restored upon resume. Thanks for reviewing, Best regards, Fabrice > >> + >> + return pwm_apply_state(&priv->chip.pwms[0], &priv->suspend); >> +} >> +#endif >> + >> +static SIMPLE_DEV_PM_OPS(stm32_pwm_lp_pm_ops, stm32_pwm_lp_suspend, >> + stm32_pwm_lp_resume); >> + >> static const struct of_device_id stm32_pwm_lp_of_match[] = { >> { .compatible = "st,stm32-pwm-lp", }, >> {}, >> @@ -235,6 +272,7 @@ static int stm32_pwm_lp_remove(struct platform_device *pdev) >> .driver = { >> .name = "stm32-pwm-lp", >> .of_match_table = of_match_ptr(stm32_pwm_lp_of_match), >> + .pm = &stm32_pwm_lp_pm_ops, >> }, >> }; >> module_platform_driver(stm32_pwm_lp_driver); >> -- >> 1.9.1 >>