+bool ltdc_crtc_scanoutpos(struct drm_device *ddev, unsigned int pipe,
+ bool in_vblank_irq, int *vpos, int *hpos,
+ ktime_t *stime, ktime_t *etime,
+ const struct drm_display_mode *mode)
+{
+ struct ltdc_device *ldev = ddev->dev_private;
+ int line, vactive_start, vactive_end, vtotal;
+
+ if (stime)
+ *stime = ktime_get();
+
+ /* The active area starts after vsync + front porch and ends
+ * at vsync + front porc + display size.
+ * The total height also include back porch.
+ * We have 3 possible cases to handle:
+ * - line < vactive_start: vpos = line - vactive_start and will be
+ * negative
+ * - vactive_start < line < vactive_end: vpos = line - vactive_start
+ * and will be positive
+ * - line > vactive_end: vpos = line - vtotal - vactive_start
+ * and will negative
+ *
+ * Computation for the two first cases are identical so we can
+ * simplify the code and only test if line > vactive_end
+ */
+ line = reg_read(ldev->regs, LTDC_CPSR) & CPSR_CYPOS;
+ vactive_start = reg_read(ldev->regs, LTDC_BPCR) & BPCR_AVBP;
+ vactive_end = reg_read(ldev->regs, LTDC_AWCR) & AWCR_AAH;
+ vtotal = reg_read(ldev->regs, LTDC_TWCR) & TWCR_TOTALH;
+
+ if (line > vactive_end)
+ *vpos = line - vtotal - vactive_start;
+ else
+ *vpos = line - vactive_start;
+
+ *hpos = 0;
+
+ if (etime)
+ *etime = ktime_get();
+
+ return true;
+}
+