From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Robin van der Gracht Subject: [PATCH v2] pwm: pwm-mxs: Wait for configuration to apply before disabling PWM. Date: Wed, 26 Jun 2013 12:26:13 +0200 Message-Id: <1372242373-17962-1-git-send-email-robin@protonic.nl> List-ID: To: thierry.reding@gmail.com Cc: linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org, shawn.guo@linaro.org, robin@protonic.nl We have to be sure that the last configuration has been applied. In most cases drivers will have set the duty-cycle to 0%. To prevent the PWM from locking at a 100% duty-cycle, we delay disabling the PWM for a whole period to make sure any new configuration has been latched. Signed-off-by: Robin van der Gracht --- drivers/pwm/pwm-mxs.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c index a53d309..7e1fa0a 100644 --- a/drivers/pwm/pwm-mxs.c +++ b/drivers/pwm/pwm-mxs.c @@ -10,6 +10,7 @@ */ #include +#include #include #include #include @@ -113,6 +114,12 @@ static int mxs_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); + unsigned int period; + + /* Ensure latest configuration applied. */ + period = pwm_get_period(pwm); + period = DIV_ROUND_UP(period, NSEC_PER_USEC); + usleep_range(period, period + 1000); writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR); -- 1.7.9.5