Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751037AbbEYNUP (ORCPT ); Mon, 25 May 2015 09:20:15 -0400 Received: from down.free-electrons.com ([37.187.137.238]:32925 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750800AbbEYNUN (ORCPT ); Mon, 25 May 2015 09:20:13 -0400 From: Alexandre Belloni To: Thierry Reding Cc: Nicolas Ferre , linux-pwm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexandre Belloni Subject: [PATCH 1/2] PWM: atmel: fix incorrect CDTY value after enabling Date: Mon, 25 May 2015 15:19:55 +0200 Message-Id: <1432559996-4415-1-git-send-email-alexandre.belloni@free-electrons.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2308 Lines: 63 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 --- 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, -- 2.1.4 -- 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/