From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53390 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756169AbeDVOJt (ORCPT ); Sun, 22 Apr 2018 10:09:49 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ryo Kodama , Yoshihiro Shimoda , Thierry Reding Subject: [PATCH 4.14 110/164] pwm: rcar: Fix a condition to prevent mismatch value setting to duty Date: Sun, 22 Apr 2018 15:52:57 +0200 Message-Id: <20180422135139.921304179@linuxfoundation.org> In-Reply-To: <20180422135135.400265110@linuxfoundation.org> References: <20180422135135.400265110@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ryo Kodama commit 6225f9c64b40bc8a22503e9cda70f55d7a9dd3c6 upstream. This patch fixes an issue that is possible to set mismatch value to duty for R-Car PWM if we input the following commands: # cd /sys/class/pwm// # echo 0 > export # cd pwm0 # echo 30 > period # echo 30 > duty_cycle # echo 0 > duty_cycle # cat duty_cycle 0 # echo 1 > enable --> Then, the actual duty_cycle is 30, not 0. So, this patch adds a condition into rcar_pwm_config() to fix this issue. Signed-off-by: Ryo Kodama [shimoda: revise the commit log and add Fixes and Cc tags] Fixes: ed6c1476bf7f ("pwm: Add support for R-Car PWM Timer") Cc: Cc: # v4.4+ Signed-off-by: Yoshihiro Shimoda Signed-off-by: Thierry Reding Signed-off-by: Greg Kroah-Hartman --- drivers/pwm/pwm-rcar.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/pwm/pwm-rcar.c +++ b/drivers/pwm/pwm-rcar.c @@ -156,8 +156,12 @@ static int rcar_pwm_config(struct pwm_ch if (div < 0) return div; - /* Let the core driver set pwm->period if disabled and duty_ns == 0 */ - if (!pwm_is_enabled(pwm) && !duty_ns) + /* + * Let the core driver set pwm->period if disabled and duty_ns == 0. + * But, this driver should prevent to set the new duty_ns if current + * duty_cycle is not set + */ + if (!pwm_is_enabled(pwm) && !duty_ns && !pwm->state.duty_cycle) return 0; rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);