drm/imx: parallel-display: fix drm_panel support

The parallel-display driver used an undocumented, non-standard property
"fsl,panel" to optionally associate with a drm_panel device. This patch
fixes the driver to use the same OF graph bindings as the LDB driver
instead:

    parallel-display {
            compatible = "fsl,imx-parallel-display";
            ...

            port@1 {
                    reg = <1>;

                    parallel_out: endpoint {
                            remote_endpoint = <&panel_in>;
                    };
            };
    };

    panel {
            ...

            port {
                    panel_in: endpoint {
                            remote-endpoint = <&parallel_out>;
                    };
            };
    };

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Gary Bisson <gary.bisson@boundarydevices.com>

1 files changed, 15 insertions, 6 deletions

diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c
index 74a9ce40ddc4..b4deb9cf9d71 100644
--- a/drivers/gpu/drm/imx/parallel-display.c
+++ b/drivers/gpu/drm/imx/parallel-display.c
@@ -21,6 +21,7 @@
 #include <drm/drm_panel.h>
 #include <linux/videodev2.h>
 #include <video/of_display_timing.h>
+#include <linux/of_graph.h>
 
 #include "imx-drm.h"
 
@@ -208,7 +209,7 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
 {
         struct drm_device *drm = data;
         struct device_node *np = dev->of_node;
-        struct device_node *panel_node;
+        struct device_node *port;
         const u8 *edidp;
         struct imx_parallel_display *imxpd;
         int ret;
@@ -234,11 +235,19 @@ static int imx_pd_bind(struct device *dev, struct device *master, void *data)
                         imxpd->bus_format = MEDIA_BUS_FMT_RGB666_1X24_CPADHI;
         }
 
-        panel_node = of_parse_phandle(np, "fsl,panel", 0);
-        if (panel_node) {
-                imxpd->panel = of_drm_find_panel(panel_node);
-                if (!imxpd->panel)
-                        return -EPROBE_DEFER;
+        /* port@1 is the output port */
+        port = of_graph_get_port_by_id(np, 1);
+        if (port) {
+                struct device_node *endpoint, *remote;
+
+                endpoint = of_get_child_by_name(port, "endpoint");
+                if (endpoint) {
+                        remote = of_graph_get_remote_port_parent(endpoint);
+                        if (remote)
+                                imxpd->panel = of_drm_find_panel(remote);
+                        if (!imxpd->panel)
+                                return -EPROBE_DEFER;
+                }
         }
 
         imxpd->dev = dev;