ACPI: utils: Add acpi_dev_uid_to_integer() helper to get _UID as integer

Some users interpret _UID only as integer and for them it's easier to
have an integer representation of _UID. Add respective helper for that.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/utils.c

@@ -793,6 +793,30 @@ bool acpi_dev_hid_uid_match(struct acpi_device *adev,
 }
 EXPORT_SYMBOL(acpi_dev_hid_uid_match);
 
+/**
+ * acpi_dev_uid_to_integer - treat ACPI device _UID as integer
+ * @adev: ACPI device to get _UID from
+ * @integer: output buffer for integer
+ *
+ * Considers _UID as integer and converts it to @integer.
+ *
+ * Returns 0 on success, or negative error code otherwise.
+ */
+int acpi_dev_uid_to_integer(struct acpi_device *adev, u64 *integer)
+{
+	const char *uid;
+
+	if (!adev)
+		return -ENODEV;
+
+	uid = acpi_device_uid(adev);
+	if (!uid)
+		return -ENODATA;
+
+	return kstrtou64(uid, 0, integer);
+}
+EXPORT_SYMBOL(acpi_dev_uid_to_integer);
+
 /**
  * acpi_dev_found - Detect presence of a given ACPI device in the namespace.
  * @hid: Hardware ID of the device.

include/acpi/acpi_bus.h

@@ -733,6 +733,7 @@ static inline bool acpi_device_can_poweroff(struct acpi_device *adev)
 }
 
 bool acpi_dev_hid_uid_match(struct acpi_device *adev, const char *hid2, const char *uid2);
+int acpi_dev_uid_to_integer(struct acpi_device *adev, u64 *integer);
 
 void acpi_dev_clear_dependencies(struct acpi_device *supplier);
 bool acpi_dev_ready_for_enumeration(const struct acpi_device *device);

include/linux/acpi.h

@@ -798,6 +798,11 @@ acpi_dev_hid_uid_match(struct acpi_device *adev, const char *hid2, const char *u
 	return false;
 }
 
+static inline int acpi_dev_uid_to_integer(struct acpi_device *adev, u64 *integer)
+{
+	return -ENODEV;
+}
+
 static inline struct acpi_device *
 acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
 {