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 <[email protected]>
---
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 <linux/clk.h>
+#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
@@ -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