[PATCH 15/72] gpu: ipu-v3: fix HDMI timing issues

[Steve Longerbeam]

From: Jiada Wang <jiada_wang at mentor.com>

On some monitors, with high resolution(1920x1080), HDMI is not working,
some resolution have pixel column truncation problem
(shows 1280x1022 instead of 1280x1024), which will result in really strange
picture on some monitors.

This Patch aims to fix these HDMI timing issues.

Signed-off-by: Jiada Wang <jiada_wang at mentor.com>
Signed-off-by: Deepak Das <deepak_das at mentor.com>
---
 drivers/gpu/ipu-v3/ipu-di.c |   30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/ipu-v3/ipu-di.c b/drivers/gpu/ipu-v3/ipu-di.c
index c490ba4..2fafb63 100644
--- a/drivers/gpu/ipu-v3/ipu-di.c
+++ b/drivers/gpu/ipu-v3/ipu-di.c
@@ -511,12 +511,35 @@ static void ipu_di_config_clock(struct ipu_di *di,
 		clk_get_rate(di->clk_di_pixel) / (clkgen0 >> 4));
 }
 
+/*
+ * This function is called to adapt synchronous LCD panel to
+ * IPU restriction.
+ */
+static void adapt_panel_to_ipu_restricitions(struct ipu_di *di,
+					     struct ipu_di_signal_cfg *sig)
+{
+	if (sig->v_end_width < 2) {
+		uint16_t diff = 2 - sig->v_end_width;
+
+		if (sig->v_start_width >= diff) {
+			sig->v_end_width = 2;
+			sig->v_start_width -= diff;
+		} else if (sig->v_sync_width > diff) {
+			sig->v_end_width = 2;
+			sig->v_sync_width = sig->v_sync_width - diff;
+		} else
+			dev_warn(di->ipu->dev, "failed to adapt timing\n");
+
+		dev_warn(di->ipu->dev,
+			 "timing adapted due to IPU restrictions\n");
+	}
+}
+
 int ipu_di_init_sync_panel(struct ipu_di *di, struct ipu_di_signal_cfg *sig)
 {
 	u32 reg;
 	u32 di_gen, vsync_cnt;
 	u32 div;
-	u32 h_total, v_total;
 
 	dev_dbg(di->ipu->dev, "disp %d: panel size = %d x %d\n",
 		di->id, sig->width, sig->height);
@@ -524,10 +547,7 @@ int ipu_di_init_sync_panel(struct ipu_di *di, struct ipu_di_signal_cfg *sig)
 	if ((sig->v_sync_width == 0) || (sig->h_sync_width == 0))
 		return -EINVAL;
 
-	h_total = sig->width + sig->h_sync_width + sig->h_start_width +
-		sig->h_end_width;
-	v_total = sig->height + sig->v_sync_width + sig->v_start_width +
-		sig->v_end_width;
+	adapt_panel_to_ipu_restricitions(di, sig);
 
 	dev_dbg(di->ipu->dev, "Clocks: IPU %luHz DI %luHz Needed %luHz\n",
 		clk_get_rate(di->clk_ipu),
-- 
1.7.9.5