pwm: ep93xx: Ensure configuring period and duty_cycle isn't wrongly skipped

As the last call to ep93xx_pwm_apply() might have exited early if
state->enabled was false, the values for period and duty_cycle stored in
pwm->state might not have been written to hardware and it must be
ensured that they are configured before enabling the PWM.

Fixes: 6d45374af539 ("pwm: ep93xx: Implement .apply callback")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 40 insertions, 45 deletions

diff --git a/drivers/pwm/pwm-ep93xx.c b/drivers/pwm/pwm-ep93xx.c
index 8a3d781e6514..fc3cb7d669c6 100644
--- a/drivers/pwm/pwm-ep93xx.c
+++ b/drivers/pwm/pwm-ep93xx.c
@@ -64,6 +64,11 @@ static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	int ret;
 	struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
 	bool enabled = state->enabled;
+	void __iomem *base = ep93xx_pwm->base;
+	unsigned long long c;
+	unsigned long period_cycles;
+	unsigned long duty_cycles;
+	unsigned long term;
 
 	if (state->polarity != pwm->state.polarity) {
 		if (enabled) {
@@ -97,57 +102,47 @@ static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		return 0;
 	}
 
-	if (state->period != pwm->state.period ||
-	    state->duty_cycle != pwm->state.duty_cycle) {
-		struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
-		void __iomem *base = ep93xx_pwm->base;
-		unsigned long long c;
-		unsigned long period_cycles;
-		unsigned long duty_cycles;
-		unsigned long term;
+	/*
+	 * The clock needs to be enabled to access the PWM registers.
+	 * Configuration can be changed at any time.
+	 */
+	if (!pwm_is_enabled(pwm)) {
+		ret = clk_prepare_enable(ep93xx_pwm->clk);
+		if (ret)
+			return ret;
+	}
 
-		/*
-		 * The clock needs to be enabled to access the PWM registers.
-		 * Configuration can be changed at any time.
-		 */
-		if (!pwm_is_enabled(pwm)) {
-			ret = clk_prepare_enable(ep93xx_pwm->clk);
-			if (ret)
-				return ret;
-		}
+	c = clk_get_rate(ep93xx_pwm->clk);
+	c *= state->period;
+	do_div(c, 1000000000);
+	period_cycles = c;
+
+	c = period_cycles;
+	c *= state->duty_cycle;
+	do_div(c, state->period);
+	duty_cycles = c;
 
-		c = clk_get_rate(ep93xx_pwm->clk);
-		c *= state->period;
-		do_div(c, 1000000000);
-		period_cycles = c;
-
-		c = period_cycles;
-		c *= state->duty_cycle;
-		do_div(c, state->period);
-		duty_cycles = c;
-
-		if (period_cycles < 0x10000 && duty_cycles < 0x10000) {
-			term = readw(base + EP93XX_PWMx_TERM_COUNT);
-
-			/* Order is important if PWM is running */
-			if (period_cycles > term) {
-				writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
-				writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
-			} else {
-				writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
-				writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
-			}
-			ret = 0;
+	if (period_cycles < 0x10000 && duty_cycles < 0x10000) {
+		term = readw(base + EP93XX_PWMx_TERM_COUNT);
+
+		/* Order is important if PWM is running */
+		if (period_cycles > term) {
+			writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
+			writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
 		} else {
-			ret = -EINVAL;
+			writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
+			writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
 		}
+		ret = 0;
+	} else {
+		ret = -EINVAL;
+	}
 
-		if (!pwm_is_enabled(pwm))
-			clk_disable_unprepare(ep93xx_pwm->clk);
+	if (!pwm_is_enabled(pwm))
+		clk_disable_unprepare(ep93xx_pwm->clk);
 
-		if (ret)
-			return ret;
-	}
+	if (ret)
+		return ret;
 
 	if (!enabled) {
 		ret = clk_prepare_enable(ep93xx_pwm->clk);