[PATCH 4/6] pwm: sun4i: simplify calculation of the delay time

[Roman Beranek]

There's no reason to expect a single jiffy has passed since writing
the CTRL register except if a preemption has occured in the meantime.
Avoid introducing unnecessary complexity and simply wait for the whole
period.

Signed-off-by: Roman Beranek <roman.beranek at prusa3d.com>
---
 drivers/pwm/pwm-sun4i.c | 17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index b3ec59a83d00..8218173ce3f6 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -14,7 +14,6 @@
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/io.h>
-#include <linux/jiffies.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
@@ -89,7 +88,6 @@ struct sun4i_pwm_chip {
 	void __iomem *base;
 	struct mutex ctrl_lock;
 	const struct sun4i_pwm_data *data;
-	unsigned long next_period[2];
 };
 
 static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip)
@@ -242,8 +240,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	struct pwm_state cstate;
 	u32 ctrl, duty = 0, period = 0, val;
 	int ret;
-	unsigned int delay_us, prescaler = 0;
-	unsigned long now;
+	unsigned int prescaler = 0;
 	bool bypass;
 
 	pwm_get_state(pwm, &cstate);
@@ -291,8 +288,6 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	val = (duty & PWM_DTY_MASK) | PWM_PRD(period);
 	sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm));
-	sun4i_pwm->next_period[pwm->hwpwm] = jiffies +
-		nsecs_to_jiffies(cstate.period + 1000);
 
 	if (state->polarity != PWM_POLARITY_NORMAL)
 		ctrl &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm);
@@ -314,15 +309,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	}
 
 	/* We need a full period to elapse before disabling the channel. */
-	now = jiffies;
-	if (time_before(now, sun4i_pwm->next_period[pwm->hwpwm])) {
-		delay_us = jiffies_to_usecs(sun4i_pwm->next_period[pwm->hwpwm] -
-					   now);
-		if ((delay_us / 500) > MAX_UDELAY_MS)
-			msleep(delay_us / 1000 + 1);
-		else
-			usleep_range(delay_us, delay_us * 2);
-	}
+	fsleep(cstate.period / NSEC_PER_USEC + 1);
 
 	ctrl &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm);
 	sun4i_pwm_writel(sun4i_pwm, ctrl, PWM_CTRL_REG);
-- 
2.31.1