Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752639AbdGELJ5 (ORCPT ); Wed, 5 Jul 2017 07:09:57 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:34409 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752058AbdGELJz (ORCPT ); Wed, 5 Jul 2017 07:09:55 -0400 Subject: Re: [PATCH v3 2/6] pwm: mediatek: fix pwm source clock selection To: Zhi Mao , john@phrozen.org, Thierry Reding , Rob Herring , Mark Rutland , linux-pwm@vger.kernel.org Cc: srv_heupstream@mediatek.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, yingjoe.chen@mediatek.com, yt.shen@mediatek.com, sean.wang@mediatek.com, zhenbao.liu@mediatek.com References: <1498802721-32455-1-git-send-email-zhi.mao@mediatek.com> <1498802721-32455-3-git-send-email-zhi.mao@mediatek.com> From: Matthias Brugger Message-ID: Date: Wed, 5 Jul 2017 13:09:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <1498802721-32455-3-git-send-email-zhi.mao@mediatek.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1123 Lines: 35 On 06/30/2017 08:05 AM, Zhi Mao wrote: > In original code, the pwm output frequency is not correct > when set bit<3>=1 to PWMCON register. > > Signed-off-by: Zhi Mao > --- > drivers/pwm/pwm-mediatek.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c > index 5c11bc7..d08b5b3 100644 > --- a/drivers/pwm/pwm-mediatek.c > +++ b/drivers/pwm/pwm-mediatek.c > @@ -91,7 +91,7 @@ static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > if (clkdiv > 7) > return -EINVAL; > > - mtk_pwm_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | BIT(3) | clkdiv); > + mtk_pwm_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv); Just for clarification, BIT(15) enables old PWM mode, which ignores CLKSEL (BIT(3)). Therefore setting BIT(3) does not have any effect and can be discarded. Am I correct? I took mt7623n datasheet for reference. Regards, Matthias > mtk_pwm_writel(pc, pwm->hwpwm, PWMDWIDTH, period_ns / resolution); > mtk_pwm_writel(pc, pwm->hwpwm, PWMTHRES, duty_ns / resolution); > >