[PATCH v3 2/2] pwm: loongson: Reload PWM configuration through counter reset

From: Keguang Zhang <[email protected]>

The Loongson PWM controller latches the LOW and PERIOD registers only at
the start of each PWM period. After disabling and re-enabling the PWM,
the controller resumes from the previous counter value and completes the
current period before re-latching the updated LOW and PERIOD values.

Reset the PWM counter when disabling the PWM and release it when
enabling the PWM so that the updated LOW and PERIOD values are latched
before the PWM starts running again.

Fixes: 2b62c89448dd ("pwm: Add Loongson PWM controller support")
Signed-off-by: Keguang Zhang <[email protected]>
---
 drivers/pwm/pwm-loongson.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/pwm/pwm-loongson.c b/drivers/pwm/pwm-loongson.c
index e703217a6d5e..c317d62fe813 100644
--- a/drivers/pwm/pwm-loongson.c
+++ b/drivers/pwm/pwm-loongson.c
@@ -103,6 +103,7 @@ static void pwm_loongson_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	struct pwm_loongson_ddata *ddata = to_pwm_loongson_ddata(chip);
 
 	val = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_CTRL);
+	val |= LOONGSON_PWM_CTRL_REG_RST;
 	val &= ~LOONGSON_PWM_CTRL_REG_EN;
 	pwm_loongson_writel(ddata, val, LOONGSON_PWM_REG_CTRL);
 }
@@ -113,6 +114,7 @@ static int pwm_loongson_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 	struct pwm_loongson_ddata *ddata = to_pwm_loongson_ddata(chip);
 
 	val = pwm_loongson_readl(ddata, LOONGSON_PWM_REG_CTRL);
+	val &= ~LOONGSON_PWM_CTRL_REG_RST;
 	val |= LOONGSON_PWM_CTRL_REG_EN;
 	pwm_loongson_writel(ddata, val, LOONGSON_PWM_REG_CTRL);
 

-- 
2.43.0