[PATCH v2 1/3] drm/tilcdc: Write to LCDC_END_OF_INT_IND_REG at the end of IRQ function

[Jyri Sarha]

Reorder the IRQ function so that the write to LCDC_END_OF_INT_IND_REG
is done last. The write to LCDC_END_OF_INT_IND_REG indicates to LCDC
that the interrupt service routine has completed (see section
13.3.6.1.6 in AM335x TRM). This is needed if LCDC's ipgvmodirq module
is configured for pulse interrupts.

Signed-off-by: Jyri Sarha <jsarha at ti.com>
---
 drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index 051e5e1..a06e73a 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -718,14 +718,19 @@ irqreturn_t tilcdc_crtc_irq(struct drm_crtc *crtc)
 			tilcdc_crtc->frame_intact = true;
 	}
 
-	if (priv->rev == 2) {
-		if (stat & LCDC_FRAME_DONE) {
-			tilcdc_crtc->frame_done = true;
-			wake_up(&tilcdc_crtc->frame_done_wq);
-		}
-		tilcdc_write(dev, LCDC_END_OF_INT_IND_REG, 0);
+	if (priv->rev == 1)
+		return IRQ_HANDLED;
+	/* The rest is for revision 2 only */
+
+	if (stat & LCDC_FRAME_DONE) {
+		tilcdc_crtc->frame_done = true;
+		wake_up(&tilcdc_crtc->frame_done_wq);
 	}
 
+	if (stat & LCDC_FIFO_UNDERFLOW)
+		dev_err_ratelimited(dev->dev, "%s(0x%08x): FIFO underfow",
+				    __func__, stat);
+
 	if (stat & LCDC_SYNC_LOST) {
 		dev_err_ratelimited(dev->dev, "%s(0x%08x): Sync lost",
 				    __func__, stat);
@@ -739,9 +744,10 @@ irqreturn_t tilcdc_crtc_irq(struct drm_crtc *crtc)
 		}
 	}
 
-	if (stat & LCDC_FIFO_UNDERFLOW)
-		dev_err_ratelimited(dev->dev, "%s(0x%08x): FIFO underfow",
-				    __func__, stat);
+	/* Indicate to LCDC that the interrupt service routine has
+	 * completed, see 13.3.6.1.6 in AM335x TRM.
+	 */
+	tilcdc_write(dev, LCDC_END_OF_INT_IND_REG, 0);
 
 	return IRQ_HANDLED;
 }
-- 
1.9.1