From: Guillermo Rodriguez Garcia <guille.rodriguez@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Guillermo Rodriguez <guille.rodriguez@gmail.com>
Subject: Re: [PATCH] pwm: atmel: Fix disabling of PWM channels
Date: Thu, 9 Jun 2016 18:36:31 +0200 [thread overview]
Message-ID: <CABDcavbouRueiO+fZECetfrhoNWZHJowptbvtkRNTN6zwGssbA@mail.gmail.com> (raw)
In-Reply-To: <1463137777-27103-1-git-send-email-guille.rodriguez@gmail.com>
Hello,
Any comments on this patch?
Guillermo
2016-05-13 13:09 GMT+02:00 Guillermo Rodriguez <guille.rodriguez@gmail.com>:
> When disabling a PWM channel, the PWM clock was being stopped
> immediately after writing to PWM_DIS. As a result, the disabling
> of the PWM channel did not complete properly, and the PWM output
> might be left at the wrong level.
>
> Fix this by waiting for the channel to be effectively disabled
> (by checking the PWM_SR register) before disabling the clock.
>
> Signed-off-by: Guillermo Rodriguez <guille.rodriguez@gmail.com>
> ---
> drivers/pwm/pwm-atmel.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
> index 0e4bd4e..a714434 100644
> --- a/drivers/pwm/pwm-atmel.c
> +++ b/drivers/pwm/pwm-atmel.c
> @@ -271,6 +271,16 @@ static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
> mutex_unlock(&atmel_pwm->isr_lock);
> atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm);
>
> + /*
> + * Wait for the PWM channel disable operation to be effective before
> + * stopping the clock.
> + */
> + timeout = jiffies + 2 * HZ;
> + while ((atmel_pwm_readl(atmel_pwm, PWM_SR)& (1 << pwm->hwpwm)) &&
> + time_before(jiffies, timeout)) {
> + usleep_range(10, 100);
> + }
> +
> clk_disable(atmel_pwm->clk);
> }
>
> --
> 1.7.9.5
>
--
Guillermo Rodriguez Garcia
guille.rodriguez@gmail.com
next prev parent reply other threads:[~2016-06-09 16:36 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-13 11:09 [PATCH] pwm: atmel: Fix disabling of PWM channels Guillermo Rodriguez
2016-06-09 16:36 ` Guillermo Rodriguez Garcia [this message]
2016-06-10 8:29 ` Alexandre Belloni
2016-06-13 10:31 ` Guillermo Rodriguez Garcia
2016-06-13 9:50 ` Alexandre Belloni
2016-07-11 10:16 ` [PATCH] " Thierry Reding
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