Commit f718c54c authored May 13, 2016 by Guillermo Rodriguez Committed by Thierry Reding Jul 11, 2016

pwm: atmel: Fix disabling of PWM channels



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>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

parent 396d502c

drivers/pwm/pwm-atmel.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -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);
		}