From patchwork Thu Apr 18 09:37:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Fabrice Gasnier X-Patchwork-Id: 1087474 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pwm-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=st.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=st.com header.i=@st.com header.b="VMN2Xlv9"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44lDYz4qBGz9sBV for ; Thu, 18 Apr 2019 19:38:31 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388578AbfDRJiU (ORCPT ); Thu, 18 Apr 2019 05:38:20 -0400 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:41796 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387971AbfDRJiT (ORCPT ); Thu, 18 Apr 2019 05:38:19 -0400 Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx08-00178001.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x3I9bPqK020922; Thu, 18 Apr 2019 11:38:00 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=STMicroelectronics; bh=CrmqrU1P3b3z4M4N3dbz9yDIRZmDOZLq4+eBzhG+d0U=; b=VMN2Xlv9B2c9QUZgGlHZ9VgwcMGabCXcC06CpPGOhs0RHcqV06K+AoQxQ5DtkZMlxq0m m1P6wo0C5xdFy7/SEdxSyREeuD8tWGg0EPjENytb+TPlFM35o3JMOcnYmEpmfXmucJlD rIAMSw5X+cPSf6OSVJfHUQxU+901sEM0bfg7dp9zSnX2k8n3Eu4JBUBDo3kGizi3AXpI dYFVHCw86YJcCM9sNNAJ9yQo8QhPwB8EhTSDZ9RtiNLAgS4pQL2zvjT80Yh1J9sHcT9l 8FVJXj4Zo8du7oBtIMgodC7Laltf4AJfvy73rbkxhGdVdkbD/H+nCiqpP/dzRlHt4aSf iw== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx08-00178001.pphosted.com with ESMTP id 2ru6nh4ycn-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT); Thu, 18 Apr 2019 11:38:00 +0200 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 501A83D; Thu, 18 Apr 2019 09:37:59 +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 26F3C15AC; Thu, 18 Apr 2019 09:37:59 +0000 (GMT) Received: from localhost (10.75.127.45) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 18 Apr 2019 11:37:58 +0200 From: Fabrice Gasnier To: CC: , , , , , , , , , , , Subject: [RESEND PATCH v5 3/3] pwm: core: add consumer device link Date: Thu, 18 Apr 2019 11:37:47 +0200 Message-ID: <1555580267-29299-4-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1555580267-29299-1-git-send-email-fabrice.gasnier@st.com> References: <1555580267-29299-1-git-send-email-fabrice.gasnier@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.45] X-ClientProxiedBy: SFHDAG5NODE1.st.com (10.75.127.13) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-04-18_05:, , signatures=0 Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org Add a device link between the PWM consumer and the PWM provider. This enforces the PWM user to get suspended before the PWM provider. It allows proper synchronization of suspend/resume sequences: the PWM user is responsible for properly stopping PWM, before the provider gets suspended: see [1]. Add the device link in: - of_pwm_get() - pwm_get() - devm_*pwm_get() variants as it requires a reference to the device for the PWM consumer. [1] https://lkml.org/lkml/2019/2/5/770 Suggested-by: Thierry Reding Acked-by: Uwe Kleine-König Signed-off-by: Fabrice Gasnier --- Changes in v5: - fix a style issue - use dev_warn() instead of pr_warn Changes in v4: - rework error handling following Thierry's comments - turn/split pr_debug() into dev_err()/pr_warn(). Changes in v3: - add struct device to of_get_pwm() arguments to handle device link from there as discussed with Uwe. --- drivers/pwm/core.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++--- include/linux/pwm.h | 6 ++++-- 2 files changed, 51 insertions(+), 5 deletions(-) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 3149204..e8d4958 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -639,8 +639,35 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np) return ERR_PTR(-EPROBE_DEFER); } +static struct device_link *pwm_device_link_add(struct device *dev, + struct pwm_device *pwm) +{ + struct device_link *dl; + + if (!dev) { + /* + * No device for the PWM consumer has been provided. It may + * impact the PM sequence ordering: the PWM supplier may get + * suspended before the consumer. + */ + dev_warn(pwm->chip->dev, + "No consumer device specified to create a link to\n"); + return NULL; + } + + dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER); + if (!dl) { + dev_err(dev, "failed to create device link to %s\n", + dev_name(pwm->chip->dev)); + return ERR_PTR(-EINVAL); + } + + return dl; +} + /** * of_pwm_get() - request a PWM via the PWM framework + * @dev: device for PWM consumer * @np: device node to get the PWM from * @con_id: consumer name * @@ -658,10 +685,12 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np) * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded * error code on failure. */ -struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id) +struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np, + const char *con_id) { struct pwm_device *pwm = NULL; struct of_phandle_args args; + struct device_link *dl; struct pwm_chip *pc; int index = 0; int err; @@ -692,6 +721,14 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id) if (IS_ERR(pwm)) goto put; + dl = pwm_device_link_add(dev, pwm); + if (IS_ERR(dl)) { + /* of_xlate ended up calling pwm_request_from_chip() */ + pwm_free(pwm); + pwm = ERR_CAST(dl); + goto put; + } + /* * If a consumer name was not given, try to look it up from the * "pwm-names" property if it exists. Otherwise use the name of @@ -767,6 +804,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) const char *dev_id = dev ? dev_name(dev) : NULL; struct pwm_device *pwm; struct pwm_chip *chip; + struct device_link *dl; unsigned int best = 0; struct pwm_lookup *p, *chosen = NULL; unsigned int match; @@ -774,7 +812,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) /* look up via DT first */ if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) - return of_pwm_get(dev->of_node, con_id); + return of_pwm_get(dev, dev->of_node, con_id); /* * We look up the provider in the static table typically provided by @@ -851,6 +889,12 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) if (IS_ERR(pwm)) return pwm; + dl = pwm_device_link_add(dev, pwm); + if (IS_ERR(dl)) { + pwm_free(pwm); + return ERR_CAST(dl); + } + pwm->args.period = chosen->period; pwm->args.polarity = chosen->polarity; @@ -942,7 +986,7 @@ struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np, if (!ptr) return ERR_PTR(-ENOMEM); - pwm = of_pwm_get(np, con_id); + pwm = of_pwm_get(dev, np, con_id); if (!IS_ERR(pwm)) { *ptr = pwm; devres_add(dev, ptr); diff --git a/include/linux/pwm.h b/include/linux/pwm.h index b628abf..7dad301 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -405,7 +405,8 @@ struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args); struct pwm_device *pwm_get(struct device *dev, const char *con_id); -struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id); +struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np, + const char *con_id); void pwm_put(struct pwm_device *pwm); struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id); @@ -493,7 +494,8 @@ static inline struct pwm_device *pwm_get(struct device *dev, return ERR_PTR(-ENODEV); } -static inline struct pwm_device *of_pwm_get(struct device_node *np, +static inline struct pwm_device *of_pwm_get(struct device *dev, + struct device_node *np, const char *con_id) { return ERR_PTR(-ENODEV);