[media] v4l: s5p-tv: mixer: fix handling of interlaced modes

The next frame was fetched by Mixer at every VSYNC event.  This caused tearing
when Mixer's output in interlaced mode.  This patch fixes this bug by fetching
new frame every second VSYNC when working in interlaced mode.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/s5p-tv/mixer.h

@@ -226,6 +226,7 @@ struct mxr_resources {
 /* event flags used  */
 enum mxr_devide_flags {
 	MXR_EVENT_VSYNC = 0,
+	MXR_EVENT_TOP = 1,
 };
 
 /** drivers instance */

drivers/media/video/s5p-tv/mixer_reg.c

@@ -296,21 +296,25 @@ irqreturn_t mxr_irq_handler(int irq, void *dev_data)
 	/* wake up process waiting for VSYNC */
 	if (val & MXR_INT_STATUS_VSYNC) {
 		set_bit(MXR_EVENT_VSYNC, &mdev->event_flags);
+		/* toggle TOP field event if working in interlaced mode */
+		if (~mxr_read(mdev, MXR_CFG) & MXR_CFG_SCAN_PROGRASSIVE)
+			change_bit(MXR_EVENT_TOP, &mdev->event_flags);
 		wake_up(&mdev->event_queue);
-	}
-
-	/* clear interrupts */
-	if (~val & MXR_INT_EN_VSYNC) {
 		/* vsync interrupt use different bit for read and clear */
-		val &= ~MXR_INT_EN_VSYNC;
+		val &= ~MXR_INT_STATUS_VSYNC;
 		val |= MXR_INT_CLEAR_VSYNC;
 	}
+
+	/* clear interrupts */
 	mxr_write(mdev, MXR_INT_STATUS, val);
 
 	spin_unlock(&mdev->reg_slock);
 	/* leave on non-vsync event */
 	if (~val & MXR_INT_CLEAR_VSYNC)
 		return IRQ_HANDLED;
+	/* skip layer update on bottom field */
+	if (!test_bit(MXR_EVENT_TOP, &mdev->event_flags))
+		return IRQ_HANDLED;
 	for (i = 0; i < MXR_MAX_LAYERS; ++i)
 		mxr_irq_layer_handle(mdev->layer[i]);
 	return IRQ_HANDLED;
@@ -333,6 +337,7 @@ void mxr_reg_streamon(struct mxr_device *mdev)
 
 	/* start MIXER */
 	mxr_write_mask(mdev, MXR_STATUS, ~0, MXR_STATUS_REG_RUN);
+	set_bit(MXR_EVENT_TOP, &mdev->event_flags);
 
 	spin_unlock_irqrestore(&mdev->reg_slock, flags);
 }