[PATCH v2] ACPI: device_sysfs: Add sysfs support for _PLD

[Won Chung <wonchung@google.com>]

When ACPI table includes _PLD fields for a device, create a new file
(pld) in sysfs to share _PLD fields.

Signed-off-by: Won Chung <wonchung@google.com>
---
 Documentation/ABI/testing/sysfs-bus-acpi | 53 ++++++++++++++++++++++++
 drivers/acpi/device_sysfs.c              | 42 +++++++++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-acpi b/Documentation/ABI/testing/sysfs-bus-acpi
index 58abacf59b2a..7f4544c9d563 100644
--- a/Documentation/ABI/testing/sysfs-bus-acpi
+++ b/Documentation/ABI/testing/sysfs-bus-acpi
@@ -96,3 +96,56 @@ Description:
 		hardware, if the _HRV control method is present.  It is mostly
 		useful for non-PCI devices because lspci can list the hardware
 		version for PCI devices.
+
+What:		/sys/bus/acpi/devices/.../pld
+Date:		Jan, 2022
+Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
+Description:
+		This attribute contains the output of the device object's
+		_PLD control method, if present. This information provides
+		details on physical location of a port.
+
+		Description on each _PLD field from ACPI specification:
+
+		===============	============================================
+		GROUP_TOKEN	Unique numerical value identifying a group.
+		GROUP_POSITION	Identifies this device connection point’s
+				position in the group.
+		USER_VISIBLE	Set if the device connection point can be
+				seen by the user without disassembly.
+		DOCK		Set if the device connection point resides
+				in a docking station or port replicator.
+		BAY		Set if describing a device in a bay or if
+				device connection point is a bay.
+		LID		Set if this device connection point resides
+				on the lid of laptop system.
+		PANEL		Describes which panel surface of the system’s
+				housing the device connection point resides on:
+				0 - Top
+				1 - Bottom
+				2 - Left
+				3 - Right
+				4 - Front
+				5 - Back
+				6 - Unknown (Vertical Position and Horizontal
+				Position will be ignored)
+		HORIZONTAL_	0 - Left
+		POSITION	1 - Center
+				2 - Right
+		VERTICAL_	0 - Upper
+		POSITION	1 - Center
+				2 - Lower
+		SHAPE		Describes the shape of the device connection
+				point.
+				0 - Round
+				1 - Oval
+				2 - Square
+				3 - Vertical Rectangle
+				4 - Horizontal Rectangle
+				5 - Vertical Trapezoid
+				6 - Horizontal Trapezoid
+				7 - Unknown - Shape rendered as a Rectangle
+				with dotted lines
+				8 - Chamfered
+				15:9 - Reserved
+		===============	===============================================
diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index d5d6403ba07b..8d4df5fb1c45 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -509,6 +509,40 @@ static ssize_t status_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(status);
 
+static ssize_t pld_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct acpi_device *acpi_dev = to_acpi_device(dev);
+	acpi_status status;
+	struct acpi_pld_info *pld;
+
+	status = acpi_get_physical_device_location(acpi_dev->handle, &pld);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	return sprintf(buf, "GROUP_TOKEN=%u\n"
+		"GROUP_POSITION=%u\n"
+		"USER_VISIBLE=%u\n"
+		"DOCK=%u\n"
+		"BAY=%u\n"
+		"LID=%u\n"
+		"PANEL=%u\n"
+		"HORIZONTAL_POSITION=%u\n"
+		"VERTICAL_POSITION=%u\n"
+		"SHAPE=%u\n",
+		pld->group_token,
+		pld->group_position,
+		pld->user_visible,
+		pld->dock,
+		pld->bay,
+		pld->lid,
+		pld->panel,
+		pld->horizontal_position,
+		pld->vertical_position,
+		pld->shape);
+}
+static DEVICE_ATTR_RO(pld);
+
 /**
  * acpi_device_setup_files - Create sysfs attributes of an ACPI device.
  * @dev: ACPI device object.
@@ -595,6 +629,12 @@ int acpi_device_setup_files(struct acpi_device *dev)
 						    &dev_attr_real_power_state);
 	}
 
+	if (acpi_has_method(dev->handle, "_PLD")) {
+		result = device_create_file(&dev->dev, &dev_attr_pld);
+		if (result)
+			goto end;
+	}
+
 	acpi_expose_nondev_subnodes(&dev->dev.kobj, &dev->data);
 
 end:
@@ -645,4 +685,6 @@ void acpi_device_remove_files(struct acpi_device *dev)
 		device_remove_file(&dev->dev, &dev_attr_status);
 	if (dev->handle)
 		device_remove_file(&dev->dev, &dev_attr_path);
+	if (acpi_has_method(dev->handle, "_PLD"))
+		device_remove_file(&dev->dev, &dev_attr_pld);
 }
-- 
2.35.0.rc0.227.g00780c9af4-goog