Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753667Ab3I0UKe (ORCPT ); Fri, 27 Sep 2013 16:10:34 -0400 Received: from top.free-electrons.com ([176.31.233.9]:47408 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751985Ab3I0UKc (ORCPT ); Fri, 27 Sep 2013 16:10:32 -0400 From: Alexandre Belloni To: Thierry Reding Cc: linux-pwm@vger.kernel.org, voice.shen@atmel.com, Nicolas Ferre , Ludovic Desroches , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Alexandre Belloni Subject: [PATCH] PWM: atmel-pwm: use request/free instead of enable/disable Date: Fri, 27 Sep 2013 22:10:28 +0200 Message-Id: <1380312628-6564-1-git-send-email-alexandre.belloni@free-electrons.com> X-Mailer: git-send-email 1.8.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2222 Lines: 66 I found that disabling a pwm while it is at a low level will actually put it back at a high level. The main symptom is that leds-pwm is calling pwm_disable() after setting the duty cycle to 0. Hence, instead of getting a switched off LED, you get an LED lit up at full brightness. Solve that by using the request and free callbacks to enable and disable the pwm channels and the clock. Signed-off-by: Alexandre Belloni --- This patch applies after: [PATCH v4] PWM: atmel-pwm: add PWM controller driver drivers/pwm/pwm-atmel.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c index 6af7a50..4526e71 100644 --- a/drivers/pwm/pwm-atmel.c +++ b/drivers/pwm/pwm-atmel.c @@ -209,7 +209,7 @@ static int atmel_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, return 0; } -static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +static int atmel_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); int ret; @@ -225,23 +225,19 @@ static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) return 0; } -static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +static void atmel_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); - u32 val; atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm); - - val = atmel_pwm_readl(atmel_pwm, PWM_SR); - if ((val & PWM_SR_ALL_CH_ON) == 0) - clk_disable(atmel_pwm->clk); + clk_disable(atmel_pwm->clk); } static const struct pwm_ops atmel_pwm_ops = { .config = atmel_pwm_config, .set_polarity = atmel_pwm_set_polarity, - .enable = atmel_pwm_enable, - .disable = atmel_pwm_disable, + .request = atmel_pwm_request, + .free = atmel_pwm_free, .owner = THIS_MODULE, }; -- 1.8.1.2 -- 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/