drm/sun4i: Add support for traversing graph with TCON TOP

TCON TOP is different from other nodes in graph by having 3 input and 3
output ports. Additionally, connection to TV TCON might lead back to
HDMI mux input port, creating loops.

Add support for traversing such graph.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180625120304.7543-9-jernej.skrabec@siol.net

diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.c b/drivers/gpu/drm/sun4i/sun4i_drv.c
index 20193d6..e6c62c0 100644 (file)
--- a/drivers/gpu/drm/sun4i/sun4i_drv.c
+++ b/drivers/gpu/drm/sun4i/sun4i_drv.c
@@ -26,6 +26,7 @@
 #include "sun4i_frontend.h"
 #include "sun4i_framebuffer.h"
 #include "sun4i_tcon.h"
+#include "sun8i_tcon_top.h"
 
 DEFINE_DRM_GEM_CMA_FOPS(sun4i_drv_fops);
 
@@ -197,6 +198,11 @@ static bool sun4i_drv_node_is_tcon(struct device_node *node)
        return !!of_match_node(sun4i_tcon_of_table, node);
 }
 
+static bool sun4i_drv_node_is_tcon_top(struct device_node *node)
+{
+       return !!of_match_node(sun8i_tcon_top_of_table, node);
+}
+
 static int compare_of(struct device *dev, void *data)
 {
        DRM_DEBUG_DRIVER("Comparing of node %pOF with %pOF\n",
@@ -258,6 +264,18 @@ static void sun4i_drv_traverse_endpoints(struct endpoint_list *list,
                if (sun4i_drv_node_is_tcon(node)) {
                        struct of_endpoint endpoint;
 
+                       /*
+                        * TCON TOP is always probed before TCON. However, TCON
+                        * points back to TCON TOP when it is source for HDMI.
+                        * We have to skip it here to prevent infinite looping
+                        * between TCON TOP and TCON.
+                        */
+                       if (sun4i_drv_node_is_tcon_top(remote)) {
+                               DRM_DEBUG_DRIVER("TCON output endpoint is TCON TOP... skipping\n");
+                               of_node_put(remote);
+                               continue;
+                       }
+
                        if (of_graph_parse_endpoint(ep, &endpoint)) {
                                DRM_DEBUG_DRIVER("Couldn't parse endpoint\n");
                                of_node_put(remote);
@@ -318,6 +336,12 @@ static int sun4i_drv_add_endpoints(struct device *dev,
        /* each node has at least one output */
        sun4i_drv_traverse_endpoints(list, node, 1);
 
+       /* TCON TOP has second and third output */
+       if (sun4i_drv_node_is_tcon_top(node)) {
+               sun4i_drv_traverse_endpoints(list, node, 3);
+               sun4i_drv_traverse_endpoints(list, node, 5);
+       }
+
        return count;
 }