uint period_ns;
        uint duty_ns;
        bool enable;
+       bool polarity;
 };
 
 struct sandbox_pwm_priv {
        return 0;
 }
 
+static int sandbox_pwm_set_invert(struct udevice *dev, uint channel,
+                                 bool polarity)
+{
+       struct sandbox_pwm_priv *priv = dev_get_priv(dev);
+       struct sandbox_pwm_chan *chan;
+
+       if (channel >= NUM_CHANNELS)
+               return -ENOSPC;
+       chan = &priv->chan[channel];
+       chan->polarity = polarity;
+
+       return 0;
+}
+
 static const struct pwm_ops sandbox_pwm_ops = {
        .set_config     = sandbox_pwm_set_config,
        .set_enable     = sandbox_pwm_set_enable,
+       .set_invert     = sandbox_pwm_set_invert,
 };
 
 static const struct udevice_id sandbox_pwm_ids[] = {
 
        ut_assertok(pwm_set_enable(dev, 1, true));
        ut_assertok(pwm_set_enable(dev, 2, true));
        ut_asserteq(-ENOSPC, pwm_set_enable(dev, 3, true));
+       ut_assertok(pwm_set_invert(dev, 0, true));
 
        ut_assertok(uclass_get_device(UCLASS_PWM, 1, &dev));
        ut_asserteq(-ENODEV, uclass_get_device(UCLASS_PWM, 2, &dev));