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Date:   Mon, 28 Feb 2022 19:06:49 +0000
Message-Id: <20220228190649.362070-1-wonchung@google.com>
Mime-Version: 1.0
Subject: [PATCH] usb:typec: Add sysfs support for Type C connector's physical location
From:   Won Chung <wonchung@google.com>
To:     Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Benson Leung <bleung@chromium.org>,
        Prashant Malani <pmalani@chromium.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Won Chung <wonchung@google.com>
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Precedence: bulk

When ACPI table includes _PLD field for a Type C connector, share _PLD
values in its sysfs. _PLD stands for physical location of device.

Currently without connector's location information, when there are
multiple Type C ports, it is hard to distinguish which connector
corresponds to which physical port at which location. For example, when
there are two Type C connectors, it is hard to find out which connector
corresponds to the Type C port on the left panel versus the Type C port
on the right panel. With location information provided, we can determine
which specific device at which location is doing what.

_PLD output includes much more fields, but only generic fields are added
and exposed to sysfs, so that non-ACPI devices can also support it in
the future. The minimal generic fields needed for locating a port are
the following.
- panel
- horizontal_position
- vertical_position
- dock
- lid

Signed-off-by: Won Chung <wonchung@google.com>
---
 Documentation/ABI/testing/sysfs-class-typec | 43 +++++++++++++++++
 drivers/usb/typec/class.c                   | 52 +++++++++++++++++++++
 drivers/usb/typec/class.h                   |  3 ++
 3 files changed, 98 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/AB=
I/testing/sysfs-class-typec
index 75088ecad202..2879bc6e6ad2 100644
--- a/Documentation/ABI/testing/sysfs-class-typec
+++ b/Documentation/ABI/testing/sysfs-class-typec
@@ -141,6 +141,49 @@ Description:
 		- "reverse": CC2 orientation
 		- "unknown": Orientation cannot be determined.
=20
+What:		/sys/class/typec/<port>/location/panel
+Date:		February 2022
+Contact:	Won Chung <wonchung@google.com>
+Description:
+		Describes which panel surface of the system=E2=80=99s housing the
+		Type C port resides on:
+		0 - Top
+		1 - Bottom
+		2 - Left
+		3 - Right
+		4 - Front
+		5 - Back
+		6 - Unknown (Vertical Position and Horizontal Position will be
+		ignored)
+
+What:		/sys/class/typec/<port>/location/vertical_position
+Date:		February 2022
+Contact:	Won Chung <wonchung@google.com>
+Description:
+		0 - Upper
+		1 - Center
+		2 - Lower
+
+What:		/sys/class/typec/<port>/location/horizontal_position
+Date:		Feb, 2022
+Contact:	Won Chung <wonchung@google.com>
+Description:
+		0 - Left
+		1 - Center
+		2 - Right
+
+What:		/sys/class/typec/<port>/location/dock
+Date:		Feb, 2022
+Contact:	Won Chung <wonchung@google.com>
+Description:
+		Set if the port resides in a docking station or a port replicator.
+
+What:		/sys/class/typec/<port>/location/lid
+Date:		Feb, 2022
+Contact:	Won Chung <wonchung@google.com>
+Description:
+		Set if the port resides on the lid of laptop system.
+
 USB Type-C partner devices (eg. /sys/class/typec/port0-partner/)
=20
 What:		/sys/class/typec/<port>-partner/accessory_mode
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 45a6f0c807cb..43b23c221f95 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -1579,8 +1579,40 @@ static const struct attribute_group typec_group =3D =
{
 	.attrs =3D typec_attrs,
 };
=20
+#define DEV_ATTR_LOCATION_PROP(prop) \
+	static ssize_t prop##_show(struct device *dev, struct device_attribute *a=
ttr, \
+		char *buf) \
+	{ \
+		struct typec_port *port =3D to_typec_port(dev); \
+		if (port->pld) \
+			return sprintf(buf, "%u\n", port->pld->prop); \
+		return 0; \
+	}; \
+static DEVICE_ATTR_RO(prop)
+
+DEV_ATTR_LOCATION_PROP(panel);
+DEV_ATTR_LOCATION_PROP(vertical_position);
+DEV_ATTR_LOCATION_PROP(horizontal_position);
+DEV_ATTR_LOCATION_PROP(dock);
+DEV_ATTR_LOCATION_PROP(lid);
+
+static struct attribute *typec_location_attrs[] =3D {
+	&dev_attr_panel.attr,
+	&dev_attr_vertical_position.attr,
+	&dev_attr_horizontal_position.attr,
+	&dev_attr_dock.attr,
+	&dev_attr_lid.attr,
+	NULL,
+};
+
+static const struct attribute_group typec_location_group =3D {
+	.name =3D "location",
+	.attrs =3D typec_location_attrs,
+};
+
 static const struct attribute_group *typec_groups[] =3D {
 	&typec_group,
+	&typec_location_group,
 	NULL
 };
=20
@@ -1614,6 +1646,24 @@ const struct device_type typec_port_dev_type =3D {
 	.release =3D typec_release,
 };
=20
+void *get_pld(struct device *dev)
+{
+#ifdef CONFIG_ACPI
+	struct acpi_pld_info *pld;
+	acpi_status status;
+
+	if (!has_acpi_companion(dev))
+		return NULL;
+
+	status =3D acpi_get_physical_device_location(ACPI_HANDLE(dev), &pld);
+	if (ACPI_FAILURE(status))
+		return NULL;
+	return pld;
+#else
+	return NULL;
+#endif
+}
+
 /* --------------------------------------- */
 /* Driver callbacks to report role updates */
=20
@@ -2073,6 +2123,8 @@ struct typec_port *typec_register_port(struct device =
*parent,
 		return ERR_PTR(ret);
 	}
=20
+	port->pld =3D get_pld(&port->dev);
+
 	ret =3D device_add(&port->dev);
 	if (ret) {
 		dev_err(parent, "failed to register port (%d)\n", ret);
diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
index 0f1bd6d19d67..1b52633400c8 100644
--- a/drivers/usb/typec/class.h
+++ b/drivers/usb/typec/class.h
@@ -3,6 +3,7 @@
 #ifndef __USB_TYPEC_CLASS__
 #define __USB_TYPEC_CLASS__
=20
+#include <linux/acpi.h>
 #include <linux/device.h>
 #include <linux/usb/typec.h>
=20
@@ -54,6 +55,8 @@ struct typec_port {
=20
 	const struct typec_capability	*cap;
 	const struct typec_operations   *ops;
+
+	struct acpi_pld_info		*pld;
 };
=20
 #define to_typec_port(_dev_) container_of(_dev_, struct typec_port, dev)
--=20
2.35.1.574.g5d30c73bfb-goog