[PATCH v5 3/8] 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 | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c 
b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index 6309d3c..65284e9 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -725,12 +725,16 @@ irqreturn_t tilcdc_crtc_irq(struct drm_crtc *crtc)
                        tilcdc_crtc->frame_intact = true;
        }

+       if (stat & LCDC_FIFO_UNDERFLOW)
+               dev_err_ratelimited(dev->dev, "%s(0x%08x): FIFO underfow",
+                                   __func__, stat);
+
+       /* For revision 2 only */
        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 (stat & LCDC_SYNC_LOST) {
                        dev_err_ratelimited(dev->dev, "%s(0x%08x): Sync lost",
@@ -743,11 +747,12 @@ irqreturn_t tilcdc_crtc_irq(struct drm_crtc *crtc)
                                             LCDC_SYNC_LOST);
                        }
                }
-       }

-       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