pwm: omap-dmtimer: Fix PWM enabling sequence

To configure DM timer in PWM mode the following needs to be set in
OMAP_TIMER_CTRL_REG using set_pwm callback:
- Set toggle mode on PORTIMERPWM output pin
- Set trigger on overflow and match on PORTIMERPWM output pin.
- Set auto reload

This is a one time configuration and needs to be set before the start of
the DM timer. But the current driver tries to set the same configuration
for every period/duty cycle update, which is not needed. So move the PWM
setup before enabling timer and do not update it in
pwm_omap_dmtimer_config().
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-omap-dmtimer.c

@@ -81,6 +81,11 @@ static int pwm_omap_dmtimer_enable(struct pwm_chip *chip,
 	struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
 
 	mutex_lock(&omap->mutex);
+	omap->pdata->set_pwm(omap->dm_timer,
+			     pwm_get_polarity(pwm) == PWM_POLARITY_INVERSED,
+			     true, OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE,
+			     true);
+
 	pwm_omap_dmtimer_start(omap);
 	mutex_unlock(&omap->mutex);
 
@@ -197,11 +202,6 @@ static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
 	dev_dbg(chip->dev, "load value: %#08x (%d), match value: %#08x (%d)\n",
 		load_value, load_value,	match_value, match_value);
 
-	omap->pdata->set_pwm(omap->dm_timer,
-			     pwm_get_polarity(pwm) == PWM_POLARITY_INVERSED,
-			     true, OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE,
-			     true);
-
 	/* If config was called while timer was running it must be reenabled. */
 	if (timer_active)
 		pwm_omap_dmtimer_start(omap);