pwm: Let pwm_get_state() return the last implemented state

When pwm_apply_state() is called the lowlevel driver usually has to
apply some rounding because the hardware doesn't support nanosecond
resolution. So let pwm_get_state() return the actually implemented state
instead of the last applied one if possible.
Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/core.c

@@ -474,7 +474,14 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
 		if (err)
 			return err;
 
-		pwm->state = *state;
+		/*
+		 * .apply might have to round some values in *state, if possible
+		 * read the actually implemented value back.
+		 */
+		if (chip->ops->get_state)
+			chip->ops->get_state(chip, pwm, &pwm->state);
+		else
+			pwm->state = *state;
 	} else {
 		/*
 		 * FIXME: restore the initial state in case of error.