From: Paul Cercueil Date: Fri, 7 Jun 2019 15:44:09 +0000 (+0200) Subject: pwm: jz4740: Force TCU2 channels to return to their init level X-Git-Tag: v5.3-rc1~179^2~24 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6580fd173070a3a494d94b40d7ca5e5a815fe29a;p=thirdparty%2Flinux.git pwm: jz4740: Force TCU2 channels to return to their init level When the PWM mode of TCU2 channels is disabled, their corresponding pin does not always return to its initial level. Force this by using a small trick: we set duty > period, which is an invalid configuration for the hardware, which then correctly resets the pin to the initial level. Signed-off-by: Paul Cercueil Signed-off-by: Thierry Reding --- diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c index e73ee72df09d0..2e4ecc061dd2d 100644 --- a/drivers/pwm/pwm-jz4740.c +++ b/drivers/pwm/pwm-jz4740.c @@ -72,7 +72,15 @@ static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { uint32_t ctrl = jz4740_timer_get_ctrl(pwm->hwpwm); - /* Disable PWM output. + /* + * Set duty > period. This trick allows the TCU channels in TCU2 mode to + * properly return to their init level. + */ + jz4740_timer_set_duty(pwm->hwpwm, 0xffff); + jz4740_timer_set_period(pwm->hwpwm, 0x0); + + /* + * Disable PWM output. * In TCU2 mode (channel 1/2 on JZ4750+), this must be done before the * counter is stopped, while in TCU1 mode the order does not matter. */