From patchwork Wed Feb 14 10:04:33 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fabrice Gasnier X-Patchwork-Id: 873296 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=) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3zhFRt3WmWz9t3C for ; Wed, 14 Feb 2018 21:06:34 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967111AbeBNKGV (ORCPT ); Wed, 14 Feb 2018 05:06:21 -0500 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:32873 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966986AbeBNKGS (ORCPT ); Wed, 14 Feb 2018 05:06:18 -0500 Received: from pps.filterd (m0046037.ppops.net [127.0.0.1]) by mx07-.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id w1EA4JT1013307; Wed, 14 Feb 2018 11:05:04 +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 2g3wfq5dyq-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT); Wed, 14 Feb 2018 11:05:04 +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 5CD4D34; Wed, 14 Feb 2018 10:05:03 +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 2BF2B2886; Wed, 14 Feb 2018 10:05:03 +0000 (GMT) Received: from localhost (10.75.127.44) by SFHDAG5NODE3.st.com (10.75.127.15) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Wed, 14 Feb 2018 11:05:02 +0100 From: Fabrice Gasnier To: , , CC: , , , , , , , , , , Subject: [RESEND PATCH v2 2/8] pwm: stm32: protect common prescaler for all channels Date: Wed, 14 Feb 2018 11:04:33 +0100 Message-ID: <1518602679-3064-3-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1518602679-3064-1-git-send-email-fabrice.gasnier@st.com> References: <1518602679-3064-1-git-send-email-fabrice.gasnier@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.44] X-ClientProxiedBy: SFHDAG5NODE1.st.com (10.75.127.13) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-02-14_03:, , signatures=0 Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org There may be a race, when configuring two pwm channels, with different prescaler values, when there's no active channel yet. Add mutex lock to avoid concurrent access on pwm apply state. This is also precursor patch for pwm capture support. Signed-off-by: Fabrice Gasnier Reviewed-by: Benjamin Gaignard --- drivers/pwm/pwm-stm32.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c index 59524f9..3ac55df 100644 --- a/drivers/pwm/pwm-stm32.c +++ b/drivers/pwm/pwm-stm32.c @@ -21,6 +21,7 @@ struct stm32_pwm { struct pwm_chip chip; + struct mutex lock; /* protect pwm config/enable */ struct clk *clk; struct regmap *regmap; u32 max_arr; @@ -213,9 +214,23 @@ static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, return ret; } +static int stm32_pwm_apply_locked(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct stm32_pwm *priv = to_stm32_pwm_dev(chip); + int ret; + + /* protect common prescaler for all active channels */ + mutex_lock(&priv->lock); + ret = stm32_pwm_apply(chip, pwm, state); + mutex_unlock(&priv->lock); + + return ret; +} + static const struct pwm_ops stm32pwm_ops = { .owner = THIS_MODULE, - .apply = stm32_pwm_apply, + .apply = stm32_pwm_apply_locked, }; static int stm32_pwm_set_breakinput(struct stm32_pwm *priv, @@ -335,6 +350,7 @@ static int stm32_pwm_probe(struct platform_device *pdev) if (!priv) return -ENOMEM; + mutex_init(&priv->lock); priv->regmap = ddata->regmap; priv->clk = ddata->clk; priv->max_arr = ddata->max_arr;