pwm: tiecap: Implement .apply() callback

To eventually get rid of all legacy drivers convert this driver to the
modern world implementing .apply(). This just pushes down a slightly
optimized variant of how legacy drivers are handled in the core.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-tiecap.c

@@ -48,16 +48,13 @@ static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip)
  * duty_ns   = 10^9 * duty_cycles / PWM_CLK_RATE
  */
 static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-		int duty_ns, int period_ns)
+			   int duty_ns, int period_ns, int enabled)
 {
 	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
 	u32 period_cycles, duty_cycles;
 	unsigned long long c;
 	u16 value;
 
-	if (period_ns > NSEC_PER_SEC)
-		return -ERANGE;
-
 	c = pc->clk_rate;
 	c = c * period_ns;
 	do_div(c, NSEC_PER_SEC);
@@ -82,7 +79,7 @@ static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	writew(value, pc->mmio_base + ECCTL2);
 
-	if (!pwm_is_enabled(pwm)) {
+	if (!enabled) {
 		/* Update active registers if not running */
 		writel(duty_cycles, pc->mmio_base + CAP2);
 		writel(period_cycles, pc->mmio_base + CAP1);
@@ -96,7 +93,7 @@ static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 		writel(period_cycles, pc->mmio_base + CAP3);
 	}
 
-	if (!pwm_is_enabled(pwm)) {
+	if (!enabled) {
 		value = readw(pc->mmio_base + ECCTL2);
 		/* Disable APWM mode to put APWM output Low */
 		value &= ~ECCTL2_APWM_MODE;
@@ -168,11 +165,49 @@ static void ecap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	pm_runtime_put_sync(pc->chip.dev);
 }
 
+static int ecap_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			  const struct pwm_state *state)
+{
+	int err;
+	int enabled = pwm->state.enabled;
+
+	if (state->polarity != pwm->state.polarity) {
+
+		if (enabled) {
+			ecap_pwm_disable(chip, pwm);
+			enabled = false;
+		}
+
+		err = ecap_pwm_set_polarity(chip, pwm, state->polarity);
+		if (err)
+			return err;
+	}
+
+	if (!state->enabled) {
+		if (enabled)
+			ecap_pwm_disable(chip, pwm);
+		return 0;
+	}
+
+	if (state->period != pwm->state.period ||
+	    state->duty_cycle != pwm->state.duty_cycle) {
+		if (state->period > NSEC_PER_SEC)
+			return -ERANGE;
+
+		err = ecap_pwm_config(chip, pwm, state->duty_cycle,
+				      state->period, enabled);
+		if (err)
+			return err;
+	}
+
+	if (!enabled)
+		return ecap_pwm_enable(chip, pwm);
+
+	return 0;
+}
+
 static const struct pwm_ops ecap_pwm_ops = {
-	.config = ecap_pwm_config,
-	.set_polarity = ecap_pwm_set_polarity,
-	.enable = ecap_pwm_enable,
-	.disable = ecap_pwm_disable,
+	.apply = ecap_pwm_apply,
 	.owner = THIS_MODULE,
 };