drm/omap: Prepare DSS for probing without legacy platform data

In order to probe display subsystem (DSS) components with ti-sysc
interconnect target module without legacy platform data and using
devicetree, we need to update dss probing a bit.

In the device tree, we will be defining the data also for the interconnect
target modules as DSS really is a private interconnect. There is some
information about that in 4460 TRM in "Figure 10-3. DSS Integration" for
example where it mentions "32-bit interconnect (SLX)".

The changes we need to make are:

1. Parse also device tree subnodes for the compatible property fixup

2. Update the component code to consider device tree subnodes

Cc: dri-devel@lists.freedesktop.org
Cc: Jyri Sarha <jsarha@ti.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 17 insertions, 8 deletions

diff --git a/drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c b/drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c
index 31502857f013..09beda9f5023 100644
--- a/drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c
+++ b/drivers/gpu/drm/omapdrm/dss/omapdss-boot-init.c
@@ -183,9 +183,24 @@ static const struct of_device_id omapdss_of_fixups_whitelist[] __initconst = {
 	{},
 };
 
+static void __init omapdss_find_children(struct device_node *np)
+{
+	struct device_node *child;
+
+	for_each_available_child_of_node(np, child) {
+		if (!of_find_property(child, "compatible", NULL))
+			continue;
+
+		omapdss_walk_device(child, true);
+
+		if (of_device_is_compatible(child, "ti,sysc"))
+			omapdss_find_children(child);
+	}
+}
+
 static int __init omapdss_boot_init(void)
 {
-	struct device_node *dss, *child;
+	struct device_node *dss;
 
 	INIT_LIST_HEAD(&dss_conv_list);
 
@@ -195,13 +210,7 @@ static int __init omapdss_boot_init(void)
 		return 0;
 
 	omapdss_walk_device(dss, true);
-
-	for_each_available_child_of_node(dss, child) {
-		if (!of_find_property(child, "compatible", NULL))
-			continue;
-
-		omapdss_walk_device(child, true);
-	}
+	omapdss_find_children(dss);
 
 	while (!list_empty(&dss_conv_list)) {
 		struct dss_conv_node *n;