MLK-17275-2: drm/bridge: it6263: Add support for OF_DYNAMIC

When CONFIG_OF_DYNAMIC is used, and this driver is enabled in
devicetree, but fails to probe a physical i2c client, it should disable
it's remote endpoint, so that the DRM master device won't fail to bind
the other available devices.
Usually, the remote endpoint of this device is a DRM encoder. If a DRM
encoder fails to bind, the DRM master device will also fail to bind.
This is why, we should disable the encoder node dynamically in
devicetree.

Signed-off-by: Robert Chiras <robert.chiras@nxp.com>
Reviewed-by: Laurentiu Palcu <laurentiu.palcu@nxp.com>

diff --git a/drivers/gpu/drm/bridge/it6263.c b/drivers/gpu/drm/bridge/it6263.c
index f568e22..32a36e9 100644 (file)
--- a/drivers/gpu/drm/bridge/it6263.c
+++ b/drivers/gpu/drm/bridge/it6263.c
@@ -19,6 +19,8 @@
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
 #include <linux/regmap.h>
 
 #define REG_VENDOR_ID(n)       (0x00 + (n))    /* n: 0/1 */
@@ -798,6 +800,11 @@ static int it6263_probe(struct i2c_client *client,
 {
        struct device *dev = &client->dev;
        struct device_node *np = dev->of_node;
+#if IS_ENABLED(CONFIG_OF_DYNAMIC)
+       struct device_node *remote_node = NULL, *endpoint = NULL;
+       struct of_changeset ocs;
+       struct property *prop;
+#endif
        struct it6263 *it6263;
        int ret;
 
@@ -809,8 +816,10 @@ static int it6263_probe(struct i2c_client *client,
 
        it6263->hdmi_i2c = client;
        it6263->lvds_i2c = i2c_new_device(client->adapter, &it6263_lvds_i2c);
-       if (!it6263->lvds_i2c)
-               return -ENODEV;
+       if (!it6263->lvds_i2c) {
+               ret = -ENODEV;
+               goto of_reconfig;
+       }
 
        it6263->hdmi_regmap = devm_regmap_init_i2c(client,
                                                &it6263_hdmi_regmap_config);
@@ -879,8 +888,53 @@ static int it6263_probe(struct i2c_client *client,
 
        i2c_set_clientdata(client, it6263);
 
+       return ret;
+
 unregister_lvds_i2c:
        i2c_unregister_device(it6263->lvds_i2c);
+       if (ret == -EPROBE_DEFER)
+               return ret;
+
+of_reconfig:
+#if IS_ENABLED(CONFIG_OF_DYNAMIC)
+       endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
+       if (endpoint)
+               remote_node = of_graph_get_remote_port_parent(endpoint);
+
+       if (remote_node) {
+               int num_endpoints = 0;
+
+               /*
+                * Remote node should have two endpoints (input and output: us)
+                * If remote node has more than two endpoints, probably that it
+                * has more outputs, so there is no need to disable it.
+                */
+               endpoint = NULL;
+               while ((endpoint = of_graph_get_next_endpoint(remote_node,
+                                                             endpoint)))
+                       num_endpoints++;
+
+               if (num_endpoints > 2) {
+                       of_node_put(remote_node);
+                       return ret;
+               }
+
+               prop = devm_kzalloc(dev, sizeof(*prop), GFP_KERNEL);
+               prop->name = devm_kstrdup(dev, "status", GFP_KERNEL);
+               prop->value = devm_kstrdup(dev, "disabled", GFP_KERNEL);
+               prop->length = 9;
+               of_changeset_init(&ocs);
+               of_changeset_update_property(&ocs, remote_node, prop);
+               ret = of_changeset_apply(&ocs);
+               if (!ret)
+                       dev_warn(dev,
+                               "Probe failed. Remote port '%s' disabled\n",
+                               remote_node->full_name);
+
+               of_node_put(remote_node);
+       };
+#endif
+
        return ret;
 }