pwm: fsl-ftm: Change prototype of a helper to prepare further changes

This prepares the driver for further changes that will make it harder to
determine the pwm_chip from a given fsl_pwm_chip. To just not have to
do that, rework fsl_pwm_apply_config() to take a pwm_chip.

Link: https://lore.kernel.org/r/5f0e88afe25d6a218032891a34f963980814b760.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-fsl-ftm.c

@@ -221,10 +221,11 @@ static bool fsl_pwm_is_other_pwm_enabled(struct fsl_pwm_chip *fpc,
 		return false;
 }
 
-static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
+static int fsl_pwm_apply_config(struct pwm_chip *chip,
 				struct pwm_device *pwm,
 				const struct pwm_state *newstate)
 {
+	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
 	unsigned int duty;
 	u32 reg_polarity;
 
@@ -232,7 +233,7 @@ static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
 	bool do_write_period = false;
 
 	if (!fsl_pwm_calculate_period(fpc, newstate->period, &periodcfg)) {
-		dev_err(fpc->chip.dev, "failed to calculate new period\n");
+		dev_err(chip->dev, "failed to calculate new period\n");
 		return -EINVAL;
 	}
 
@@ -246,7 +247,7 @@ static int fsl_pwm_apply_config(struct fsl_pwm_chip *fpc,
 	 */
 	else if (!fsl_pwm_periodcfg_are_equal(&fpc->period, &periodcfg)) {
 		if (fsl_pwm_is_other_pwm_enabled(fpc, pwm)) {
-			dev_err(fpc->chip.dev,
+			dev_err(chip->dev,
 				"Cannot change period for PWM %u, disable other PWMs first\n",
 				pwm->hwpwm);
 			return -EBUSY;
@@ -322,7 +323,7 @@ static int fsl_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		goto end_mutex;
 	}
 
-	ret = fsl_pwm_apply_config(fpc, pwm, newstate);
+	ret = fsl_pwm_apply_config(chip, pwm, newstate);
 	if (ret)
 		goto end_mutex;