[PATCH] ACPI: Add identification objects' user interface.

[Lv Zheng <lv.zheng@intel.com>]

ACPI devices are glued with physical devices through _ADR object, ACPI
enumerated devices are identified with _UID object.  Currently we can
observe _HID/_CID through sysfs interfaces (hid/modalias), but there's
no mean for us to check _ADR/_UID from user space.  This patch fix this
gap for ACPI developers and users.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
---
 drivers/acpi/scan.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index bb7fe47..df53190 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -216,6 +216,22 @@ acpi_device_hid_show(struct device *dev, struct device_attribute *attr, char *bu
 static DEVICE_ATTR(hid, 0444, acpi_device_hid_show, NULL);
 
 static ssize_t
+acpi_device_uid_show(struct device *dev, struct device_attribute *attr, char *buf) {
+	struct acpi_device *acpi_dev = to_acpi_device(dev);
+
+	return sprintf(buf, "%s\n", acpi_dev->pnp.unique_id);
+}
+static DEVICE_ATTR(uid, 0444, acpi_device_uid_show, NULL);
+
+static ssize_t
+acpi_device_adr_show(struct device *dev, struct device_attribute *attr, char *buf) {
+	struct acpi_device *acpi_dev = to_acpi_device(dev);
+
+	return sprintf(buf, "0x%08x\n", (unsigned int)(acpi_dev->pnp.bus_address));
+}
+static DEVICE_ATTR(adr, 0444, acpi_device_adr_show, NULL);
+
+static ssize_t
 acpi_device_path_show(struct device *dev, struct device_attribute *attr, char *buf) {
 	struct acpi_device *acpi_dev = to_acpi_device(dev);
 	struct acpi_buffer path = {ACPI_ALLOCATE_BUFFER, NULL};
@@ -257,6 +273,11 @@ static int acpi_device_setup_files(struct acpi_device *dev)
 			goto end;
 	}
 
+	if (dev->flags.bus_address)
+		result = device_create_file(&dev->dev, &dev_attr_adr);
+	if (dev->pnp.unique_id)
+		result = device_create_file(&dev->dev, &dev_attr_uid);
+
         /*
          * If device has _EJ0, 'eject' file is created that is used to trigger
          * hot-removal function from userland.
@@ -281,6 +302,10 @@ static void acpi_device_remove_files(struct acpi_device *dev)
 	if (ACPI_SUCCESS(status))
 		device_remove_file(&dev->dev, &dev_attr_eject);
 
+	if (dev->pnp.unique_id)
+		device_remove_file(&dev->dev, &dev_attr_uid);
+	if (dev->flags.bus_address)
+		device_remove_file(&dev->dev, &dev_attr_adr);
 	device_remove_file(&dev->dev, &dev_attr_modalias);
 	device_remove_file(&dev->dev, &dev_attr_hid);
 	if (dev->handle)
-- 
1.7.10