pwm: jz4740: Implement ->set_polarity()

This permits clients of this driver to specify the polarity to use for
their PWM channel.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-jz4740.c

@@ -130,10 +130,29 @@ static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }
 
+static int jz4740_pwm_set_polarity(struct pwm_chip *chip,
+		struct pwm_device *pwm, enum pwm_polarity polarity)
+{
+	uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm);
+
+	switch (polarity) {
+	case PWM_POLARITY_NORMAL:
+		ctrl &= ~JZ_TIMER_CTRL_PWM_ACTIVE_LOW;
+		break;
+	case PWM_POLARITY_INVERSED:
+		ctrl |= JZ_TIMER_CTRL_PWM_ACTIVE_LOW;
+		break;
+	}
+
+	jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
+	return 0;
+}
+
 static const struct pwm_ops jz4740_pwm_ops = {
 	.request = jz4740_pwm_request,
 	.free = jz4740_pwm_free,
 	.config = jz4740_pwm_config,
+	.set_polarity = jz4740_pwm_set_polarity,
 	.enable = jz4740_pwm_enable,
 	.disable = jz4740_pwm_disable,
 	.owner = THIS_MODULE,