[PATCH v2 7/7] drm/rockchip: Load crtc devices in preferred order

[Jonas Karlman]

On RK3399 the VOPL is loaded before VOPB and get registered as crtc-0.
However, on RK3288 and PX30 VOPB is gets registered as crtc-0 instead of
VOPL.

With VOPL registered as crtc-0 the kernel kms client is not able to
enable 4K display modes for console use on RK3399.

Load VOPB before VOPL to help kernel kms client make use of 4K display
modes for console use on RK3399.

Signed-off-by: Jonas Karlman <jonas at kwiboo.se>
---
v2: No change
---
 drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 23 +++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
index 44d769d9234d..b84451d59187 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
@@ -354,11 +354,34 @@ static void rockchip_drm_match_remove(struct device *dev)
 		device_link_del(link);
 }
 
+/* list of preferred vop devices */
+static const char *const rockchip_drm_match_preferred[] = {
+	"rockchip,rk3399-vop-big",
+	NULL,
+};
+
 static struct component_match *rockchip_drm_match_add(struct device *dev)
 {
 	struct component_match *match = NULL;
+	struct device_node *port;
 	int i;
 
+	/* add preferred vop device match before adding driver device matches */
+	for (i = 0; ; i++) {
+		port = of_parse_phandle(dev->of_node, "ports", i);
+		if (!port)
+			break;
+
+		if (of_device_is_available(port->parent) &&
+		    of_device_compatible_match(port->parent,
+					       rockchip_drm_match_preferred))
+			drm_of_component_match_add(dev, &match,
+						   component_compare_of,
+						   port->parent);
+
+		of_node_put(port);
+	}
+
 	for (i = 0; i < num_rockchip_sub_drivers; i++) {
 		struct platform_driver *drv = rockchip_sub_drivers[i];
 		struct device *p = NULL, *d;
-- 
2.46.0