[PATCH v4 2/2] ACPI: Export PLD (Physical Location of Device)

[Samuel Ortiz <sameo@linux.intel.com>]

From: Faouaz TENOUTIT <faouaz.tenoutit@intel.com>

This patch exports a sysfs directory with ACPI _PLD information:

$ ls -l /sys/bus/acpi/devices/ACPI-DEV/pld
-r--r--r-- root     root         4096 2014-05-30 08:39 panel
-r--r--r-- root     root         4096 2014-05-30 08:39 revision
-r--r--r-- root     root         4096 2014-05-30 08:39 rotation
-r--r--r-- root     root         4096 2014-05-30 08:39 shape

This information can be used by user applications to:
- Determine which specific connector or device input mechanism may be used
  for a given task.
- Describes which panel surface of the system's housing the device
  connection point resides on (Front, Back, ...)

More information about these _PLD fields can be found here:
Documentation/ABI/testing/sysfs-bus-acpi

Signed-off-by: Faouaz TENOUTIT <faouaz.tenoutit@intel.com>
Acked-by: Samuel Ortiz <samuel.ortiz@intel.com>
Acked-by: Andrew J Ross <andrew.j.ross@intel.com>
---
 Documentation/ABI/testing/sysfs-bus-acpi | 60 ++++++++++++++++++++++++++++++++
 drivers/acpi/scan.c                      | 53 ++++++++++++++++++++++++----
 2 files changed, 107 insertions(+), 6 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-acpi b/Documentation/ABI/testing/sysfs-bus-acpi
index 7fa9cbc..be58159 100644
--- a/Documentation/ABI/testing/sysfs-bus-acpi
+++ b/Documentation/ABI/testing/sysfs-bus-acpi
@@ -56,3 +56,63 @@ Description:
 		Writing 1 to this attribute will trigger hot removal of
 		this device object.  This file exists for every device
 		object that has _EJ0 method.
+
+What:		/sys/bus/acpi/devices/.../pld
+Date:		August 2014
+Contact:	Faouaz Tenoutit <faouaz.tenoutit@intel.com>
+Description:
+		This optional directory provides description of the physical
+		location, orientation and position of external devices.
+		It is for example used to describe how camera sensors are
+		physically mounted and allows user space software to rotate
+		images accordingly.
+
+What:		/sys/bus/acpi/devices/.../pld/revision
+Date:		August 2014
+Contact:	Faouaz Tenoutit <faouaz.tenoutit@intel.com>
+Description:
+		The current Revision is 0x2
+
+What:		/sys/bus/acpi/devices/.../pld/panel
+Date:		August 2014
+Contact:	Faouaz Tenoutit <faouaz.tenoutit@intel.com>
+Description:
+		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
+
+What:		/sys/bus/acpi/devices/.../pld/shape
+Date:		August 2014
+Contact:	Faouaz Tenoutit <faouaz.tenoutit@intel.com>
+Description:
+		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
+
+What:		/sys/bus/acpi/devices/.../pld/rotation
+Date:		August 2014
+Contact:	Faouaz Tenoutit <faouaz.tenoutit@intel.com>
+Description:
+		Rotates the Shape clockwise in 45 degree steps around its
+		origin where:
+		0 0°
+		1 45°
+		2 90°
+		3 135°
+		4 180°
+		5 225°
+		6 270°
+		7 315°
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 2ca42d5..19889a3 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -686,6 +686,36 @@ static ssize_t status_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(status);
 
+#define ACPI_SYSFS_PLD_PROP(prop)				\
+	static ssize_t prop##_show(struct device *dev,		\
+			   struct device_attribute *attr,	\
+			   char *buf) {				\
+	struct acpi_device *acpi_dev = to_acpi_device(dev);     \
+	return sprintf(buf, "%d\n", acpi_dev->pld->prop);       \
+};							        \
+static DEVICE_ATTR_RO(prop)
+
+/*
+ * sysfs PLD parameters
+ */
+ACPI_SYSFS_PLD_PROP(revision);
+ACPI_SYSFS_PLD_PROP(panel);
+ACPI_SYSFS_PLD_PROP(shape);
+ACPI_SYSFS_PLD_PROP(rotation);
+
+static struct attribute *acpi_pld_attrs[] = {
+	&dev_attr_revision.attr,
+	&dev_attr_panel.attr,
+	&dev_attr_shape.attr,
+	&dev_attr_rotation.attr,
+	NULL,
+};
+
+static const struct attribute_group acpi_pld_attr_group = {
+	.name = "pld",
+	.attrs = acpi_pld_attrs,
+};
+
 static int acpi_device_setup_files(struct acpi_device *dev)
 {
 	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
@@ -768,11 +798,20 @@ static int acpi_device_setup_files(struct acpi_device *dev)
 	}
 
 	/*
-	 * If device has _PLD, initialize the 'pld' struct
+	 * If device has _PLD, 'pld' directory is created
 	 */
-	if (acpi_has_method(dev->handle, "_PLD"))
-		acpi_get_physical_device_location(dev->handle,
-						  &dev->pld);
+	if (acpi_has_method(dev->handle, "_PLD")) {
+		status = acpi_get_physical_device_location(dev->handle,
+							   &dev->pld);
+		if (ACPI_SUCCESS(status)) {
+			result = sysfs_create_group(&dev->dev.kobj,
+						    &acpi_pld_attr_group);
+			if (result) {
+				ACPI_FREE(dev->pld);
+				dev->pld = NULL;
+			}
+		}
+	}
 
 end:
 	return result;
@@ -815,10 +854,12 @@ static void acpi_device_remove_files(struct acpi_device *dev)
 		device_remove_file(&dev->dev, &dev_attr_path);
 
 	/*
-	 * If device has _PLD, free 'pld' struct
+	 * If device has _PLD, remove 'pld' directory
 	 */
-	if (dev->pld)
+	if (dev->pld) {
+		sysfs_remove_group(&dev->dev.kobj, &acpi_pld_attr_group);
 		ACPI_FREE(dev->pld);
+	}
 }
 /* --------------------------------------------------------------------------
 			ACPI Bus operations
-- 
2.0.0

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