pwm: renesas-tpu: Implement .apply() callback

To eventually get rid of all legacy drivers convert this driver to the
modern world implementing .apply().

As pwm->state might not be updated in tpu_pwm_apply() before calling
tpu_pwm_config(), an additional parameter is needed for tpu_pwm_config()
to not change the implemented logic.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

Author: Uwe Kleine-König

drivers/pwm/pwm-renesas-tpu.c

@@ -242,7 +242,7 @@ static void tpu_pwm_free(struct pwm_chip *chip, struct pwm_device *_pwm)
 }
 
 static int tpu_pwm_config(struct pwm_chip *chip, struct pwm_device *_pwm,
-			  int duty_ns, int period_ns)
+			  int duty_ns, int period_ns, bool enabled)
 {
 	static const unsigned int prescalers[] = { 1, 4, 16, 64 };
 	struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
@@ -293,7 +293,7 @@ static int tpu_pwm_config(struct pwm_chip *chip, struct pwm_device *_pwm,
 	pwm->duty = duty;
 
 	/* If the channel is disabled we're done. */
-	if (!pwm_is_enabled(_pwm))
+	if (!enabled)
 		return 0;
 
 	if (duty_only && pwm->timer_on) {
@@ -366,13 +366,45 @@ static void tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *_pwm)
 	tpu_pwm_timer_stop(pwm);
 }
 
+static int tpu_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			 const struct pwm_state *state)
+{
+	int err;
+	bool enabled = pwm->state.enabled;
+
+	if (state->polarity != pwm->state.polarity) {
+		if (enabled) {
+			tpu_pwm_disable(chip, pwm);
+			enabled = false;
+		}
+
+		err = tpu_pwm_set_polarity(chip, pwm, state->polarity);
+		if (err)
+			return err;
+	}
+
+	if (!state->enabled) {
+		if (enabled)
+			tpu_pwm_disable(chip, pwm);
+
+		return 0;
+	}
+
+	err = tpu_pwm_config(pwm->chip, pwm,
+			     state->duty_cycle, state->period, enabled);
+	if (err)
+		return err;
+
+	if (!enabled)
+		err = tpu_pwm_enable(chip, pwm);
+
+	return err;
+}
+
 static const struct pwm_ops tpu_pwm_ops = {
 	.request = tpu_pwm_request,
 	.free = tpu_pwm_free,
-	.config = tpu_pwm_config,
-	.set_polarity = tpu_pwm_set_polarity,
-	.enable = tpu_pwm_enable,
-	.disable = tpu_pwm_disable,
+	.apply = tpu_pwm_apply,
 	.owner = THIS_MODULE,
 };