Create a symlink pointing to USB Type-C connector for DRM connectors
when they are created. The link will be created only if the firmware is
able to describe the connection beween the two connectors.
Currently, even if a display uses a USB Type-C port, there is no way for
the userspace to find which port is used for which display. With the
symlink, display information would be accessible from Type-C connectors
and port information would be accessible from DRM connectors.
Associating the two subsystems, userspace would have potential to expose
and utilize more complex information, such as bandwidth used for a
specific USB Type-C port.
Signed-off-by: Won Chung <wonchung@xxxxxxxxxx>
Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
---
Changes from v3:
- Append to the commit message on why this patch is needed
Changes from v2:
- Resend the patch to dri-devel list
Changes from v1:
- Fix multiple lines to single line
drivers/gpu/drm/drm_sysfs.c | 40 +++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index 430e00b16eec..6a9904fa9186 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -11,12 +11,14 @@
*/
#include <linux/acpi.h>
+#include <linux/component.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <linux/i2c.h>
#include <linux/kdev_t.h>
+#include <linux/property.h>
#include <linux/slab.h>
#include <drm/drm_connector.h>
@@ -95,6 +97,34 @@ static char *drm_devnode(struct device *dev, umode_t *mode)
return kasprintf(GFP_KERNEL, "dri/%s", dev_name(dev));
}
+static int typec_connector_bind(struct device *dev,
+ struct device *typec_connector, void *data)
+{
+ int ret;
+
+ ret = sysfs_create_link(&dev->kobj, &typec_connector->kobj, "typec_connector");
+ if (ret)
+ return ret;
+
+ ret = sysfs_create_link(&typec_connector->kobj, &dev->kobj, "drm_connector");
+ if (ret)
+ sysfs_remove_link(&dev->kobj, "typec_connector");
+
+ return ret;
+}
+
+static void typec_connector_unbind(struct device *dev,
+ struct device *typec_connector, void *data)
+{
+ sysfs_remove_link(&typec_connector->kobj, "drm_connector");
+ sysfs_remove_link(&dev->kobj, "typec_connector");
+}
+
+static const struct component_ops typec_connector_ops = {
+ .bind = typec_connector_bind,
+ .unbind = typec_connector_unbind,
+};
+
static CLASS_ATTR_STRING(version, S_IRUGO, "drm 1.1.0 20060810");
/**
@@ -355,6 +385,13 @@ int drm_sysfs_connector_add(struct drm_connector *connector)
if (connector->ddc)
return sysfs_create_link(&connector->kdev->kobj,
&connector->ddc->dev.kobj, "ddc");
+
+ if (dev_fwnode(kdev)) {
+ r = component_add(kdev, &typec_connector_ops);
+ if (r)
+ drm_err(dev, "failed to add component\n");
+ }
+
return 0;
err_free:
@@ -367,6 +404,9 @@ void drm_sysfs_connector_remove(struct drm_connector *connector)
if (!connector->kdev)
return;
+ if (dev_fwnode(connector->kdev))
+ component_del(connector->kdev, &typec_connector_ops);
+
if (connector->ddc)
sysfs_remove_link(&connector->kdev->kobj, "ddc");
--
2.37.3.998.g577e59143f-goog
