[PATCH 4.9 55/86] drm/bridge: tc358767: filter out too high modes

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andrey Gusakov <andrey.gusakov@cogentembedded.com>


[ Upstream commit 99fc8e963a4c0203dba26a77cf737db6081bca14 ]

Pixel clock limitation for DPI is 154 MHz. Do not accept modes
with higher pixel clock rate.

Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Andrey Gusakov <andrey.gusakov@cogentembedded.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1510073785-16108-3-git-send-email-andrey.gusakov@cogentembedded.com
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/bridge/tc358767.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1109,7 +1109,10 @@ static bool tc_bridge_mode_fixup(struct
 static int tc_connector_mode_valid(struct drm_connector *connector,
 				   struct drm_display_mode *mode)
 {
-	/* Accept any mode */
+	/* DPI interface clock limitation: upto 154 MHz */
+	if (mode->clock > 154000)
+		return MODE_CLOCK_HIGH;
+
 	return MODE_OK;
 }