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-rw-r--r--Documentation/ABI/testing/sysfs-driver-typec-displayport15
-rw-r--r--drivers/usb/typec/altmodes/displayport.c10
2 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-driver-typec-displayport b/Documentation/ABI/testing/sysfs-driver-typec-displayport
index 231471ad0d4b..256c87c5219a 100644
--- a/Documentation/ABI/testing/sysfs-driver-typec-displayport
+++ b/Documentation/ABI/testing/sysfs-driver-typec-displayport
@@ -47,3 +47,18 @@ Description:
USB SuperSpeed protocol. From user perspective pin assignments C
and E are equal, where all channels on the connector are used
for carrying DisplayPort protocol (allowing higher resolutions).
+
+What: /sys/bus/typec/devices/.../displayport/hpd
+Date: Dec 2022
+Contact: Badhri Jagan Sridharan <badhri@google.com>
+Description:
+ VESA DisplayPort Alt Mode on USB Type-C Standard defines how
+ HotPlugDetect(HPD) shall be supported on the USB-C connector when
+ operating in DisplayPort Alt Mode. This is a read only node which
+ reflects the current state of HPD.
+
+ Valid values:
+ - 1: when HPD’s logical state is high (HPD_High) as defined
+ by VESA DisplayPort Alt Mode on USB Type-C Standard.
+ - 0 when HPD’s logical state is low (HPD_Low) as defined by
+ VESA DisplayPort Alt Mode on USB Type-C Standard.
diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index de66a2949e33..06fb4732f8cd 100644
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -146,6 +146,7 @@ static int dp_altmode_status_update(struct dp_altmode *dp)
if (dp->hpd != hpd) {
drm_connector_oob_hotplug_event(dp->connector_fwnode);
dp->hpd = hpd;
+ sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
}
}
@@ -508,9 +509,18 @@ static ssize_t pin_assignment_show(struct device *dev,
}
static DEVICE_ATTR_RW(pin_assignment);
+static ssize_t hpd_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct dp_altmode *dp = dev_get_drvdata(dev);
+
+ return sysfs_emit(buf, "%d\n", dp->hpd);
+}
+static DEVICE_ATTR_RO(hpd);
+
static struct attribute *dp_altmode_attrs[] = {
&dev_attr_configuration.attr,
&dev_attr_pin_assignment.attr,
+ &dev_attr_hpd.attr,
NULL
};