Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751990AbbEZJDX (ORCPT ); Tue, 26 May 2015 05:03:23 -0400 Received: from eusmtp01.atmel.com ([212.144.249.243]:35332 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751464AbbEZJDL (ORCPT ); Tue, 26 May 2015 05:03:11 -0400 Message-ID: <5564366D.9090707@atmel.com> Date: Tue, 26 May 2015 11:01:33 +0200 From: Nicolas Ferre Organization: atmel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Alexandre Belloni , Thierry Reding CC: , , Subject: Re: [PATCH 1/2] PWM: atmel: fix incorrect CDTY value after enabling References: <1432559996-4415-1-git-send-email-alexandre.belloni@free-electrons.com> In-Reply-To: <1432559996-4415-1-git-send-email-alexandre.belloni@free-electrons.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.161.30.18] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2576 Lines: 71 Le 25/05/2015 15:19, Alexandre Belloni a ?crit : > CUPD is not flushed before enabling the channel so it will update CDTY/CPRD just > after one period. So we always set CUPD, even when the channel is not enabled. > > Signed-off-by: Alexandre Belloni Acked-by: Nicolas Ferre BTW, is a "stable tag" needed for this one? > --- > drivers/pwm/pwm-atmel.c | 35 ++++++++++++++++++----------------- > 1 file changed, 18 insertions(+), 17 deletions(-) > > diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c > index d3c22de9ee47..89f9ca41d9af 100644 > --- a/drivers/pwm/pwm-atmel.c > +++ b/drivers/pwm/pwm-atmel.c > @@ -155,24 +155,25 @@ static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm, > struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); > unsigned int val; > > - if (test_bit(PWMF_ENABLED, &pwm->flags)) { > - /* > - * If the PWM channel is enabled, using the update register, > - * it needs to set bit 10 of CMR to 0 > - */ > - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty); > > - val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); > - val &= ~PWM_CMR_UPD_CDTY; > - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); > - } else { > - /* > - * If the PWM channel is disabled, write value to duty and > - * period registers directly. > - */ > - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty); > - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd); > - } > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty); > + > + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); > + val &= ~PWM_CMR_UPD_CDTY; > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); > + > + /* > + * If the PWM channel is enabled, only update CDTY by using the update > + * register, it needs to set bit 10 of CMR to 0 > + */ > + if (test_bit(PWMF_ENABLED, &pwm->flags)) > + return; > + /* > + * If the PWM channel is disabled, write value to duty and period > + * registers directly. > + */ > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty); > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd); > } > > static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm, > -- Nicolas Ferre -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/