When disabling the pwm, the output state locks at its current state. We have to be sure the last configuration applied. Which in most cases sets duty cycle to 0%. To prevent the pwm from taking on 100% duty cycle when disabled during a high state.
Configuration applies at the beginning of a new output period. Signed-off-by: Robin van der Gracht <[email protected]> --- drivers/pwm/pwm-mxs.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c index 3febddd..4ddc063 100644 --- a/drivers/pwm/pwm-mxs.c +++ b/drivers/pwm/pwm-mxs.c @@ -21,6 +21,7 @@ #include <linux/pwm.h> #include <linux/slab.h> #include <linux/stmp_device.h> +#include <linux/delay.h> #define SET 0x4 #define CLR 0x8 @@ -40,6 +41,7 @@ struct mxs_pwm_chip { struct pwm_chip chip; struct clk *clk; void __iomem *base; + unsigned long period_ns; }; #define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip) @@ -92,6 +94,7 @@ static int mxs_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, if (!test_bit(PWMF_ENABLED, &pwm->flags)) clk_disable_unprepare(mxs->clk); + mxs->period_ns = period_ns; return 0; } @@ -113,6 +116,11 @@ static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); + /* + * Ensure latest configuration applied. + */ + ndelay(mxs->period_ns); + writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR); clk_disable_unprepare(mxs->clk); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
