ACPI: Add user space interface for identification objects
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 way for us to check _ADR/_UID from user space. This patch closes
this gap for ACPI developers and users.
[rjw: Modified the subject and changelog slightly.]
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index daa88d5..86bfa69 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -220,6 +220,25 @@
}
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);
@@ -304,6 +323,11 @@
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.
@@ -335,6 +359,10 @@
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)
