[PATCH v3] usb: typec: Add sysfs node to show cc orientation

[Badhri Jagan Sridharan <badhri@xxxxxxxxxx>]

Export Type-C orientation information when available.
- "normal": CC1 orientation
- "reverse": CC2 orientation
- "unknown": Orientation cannot be determined.

Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
---
Version history:
V3:
- Heikki's suggestion to us .is_visible callback.
  unsigned int orientation_aware:1 has been introduced to
  make support of this attribute optional for drivers such
  as UCSI
- Guenter's suggestion to rename to "orientation".
- Heikki's suggestion to stick with string values instead
  of exposing it as integer values.
---
 Documentation/ABI/testing/sysfs-class-typec |  9 +++++++
 drivers/usb/typec/class.c                   | 27 +++++++++++++++++++++
 drivers/usb/typec/tcpm/tcpm.c               |  1 +
 include/linux/usb/typec.h                   |  1 +
 4 files changed, 38 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
index 0c2eb26fdc06b..b834671522d6f 100644
--- a/Documentation/ABI/testing/sysfs-class-typec
+++ b/Documentation/ABI/testing/sysfs-class-typec
@@ -108,6 +108,15 @@ Contact:	Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
 Description:
 		Revision number of the supported USB Type-C specification.
 
+What:		/sys/class/typec/<port>/orientation
+Date:		February 2020
+Contact:	Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
+Description:
+		Indicates the active orientation of the Type-C connector.
+		Valid values:
+		- "normal": CC1 orientation
+		- "reverse": CC2 orientation
+		- "unknown": Orientation cannot be determined.
 
 USB Type-C partner devices (eg. /sys/class/typec/port0-partner/)
 
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 12be5bb6d32ca..2524f1571e425 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -1244,6 +1244,26 @@ static ssize_t usb_power_delivery_revision_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(usb_power_delivery_revision);
 
+static ssize_t orientation_show(struct device *dev,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	struct typec_port *p = to_typec_port(dev);
+	enum typec_orientation orientation = typec_get_orientation(p);
+
+	switch (orientation) {
+	case TYPEC_ORIENTATION_NONE:
+		return sprintf(buf, "%s\n", "unknown");
+	case TYPEC_ORIENTATION_NORMAL:
+		return sprintf(buf, "%s\n", "normal");
+	case TYPEC_ORIENTATION_REVERSE:
+		return sprintf(buf, "%s\n", "reverse");
+	default:
+		return sprintf(buf, "%s\n", "unknown");
+	}
+}
+static DEVICE_ATTR_RO(orientation);
+
 static struct attribute *typec_attrs[] = {
 	&dev_attr_data_role.attr,
 	&dev_attr_power_operation_mode.attr,
@@ -1254,6 +1274,7 @@ static struct attribute *typec_attrs[] = {
 	&dev_attr_usb_typec_revision.attr,
 	&dev_attr_vconn_source.attr,
 	&dev_attr_port_type.attr,
+	&dev_attr_orientation.attr,
 	NULL,
 };
 
@@ -1283,6 +1304,10 @@ static umode_t typec_attr_is_visible(struct kobject *kobj,
 			return 0;
 		if (port->cap->type != TYPEC_PORT_DRP)
 			return 0444;
+	} else if (attr == &dev_attr_orientation.attr) {
+		if (port->cap->orientation_aware)
+			return 0444;
+		return 0;
 	}
 
 	return attr->mode;
@@ -1493,6 +1518,8 @@ int typec_set_orientation(struct typec_port *port,
 	}
 
 	port->orientation = orientation;
+	sysfs_notify(&port->dev.kobj, NULL, "orientation");
+	kobject_uevent(&port->dev.kobj, KOBJ_CHANGE);
 
 	return 0;
 }
diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 78077c234ef27..bc0032a6b9a14 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4742,6 +4742,7 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 	port->typec_caps.pd_revision = 0x0300;	/* USB-PD spec release 3.0 */
 	port->typec_caps.driver_data = port;
 	port->typec_caps.ops = &tcpm_ops;
+	port->typec_caps.orientation_aware = 1;
 
 	port->partner_desc.identity = &port->partner_ident;
 	port->port_type = port->typec_caps.type;
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index 44d28387ced48..b00a2642a9cd6 100644
--- a/include/linux/usb/typec.h
+++ b/include/linux/usb/typec.h
@@ -211,6 +211,7 @@ struct typec_capability {
 	u16			pd_revision; /* 0300H = "3.0" */
 	int			prefer_role;
 	enum typec_accessory	accessory[TYPEC_MAX_ACCESSORY];
+	unsigned int		orientation_aware:1;
 
 	struct fwnode_handle	*fwnode;
 	void			*driver_data;
-- 
2.25.0.265.gbab2e86ba0-goog