[PATCH v1 1/8] ACPI: utils: Introduce acpi_dev_uid_match() for matching _UID

[Raag Jadav <raag.jadav@intel.com>]

Introduce acpi_dev_uid_match() helper that matches the device with
supplied _UID string.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/acpi/utils.c    | 40 +++++++++++++++++++++++++++++++++-------
 include/acpi/acpi_bus.h |  1 +
 include/linux/acpi.h    |  5 +++++
 3 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 2ea14648a661..664b9890b625 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -768,28 +768,54 @@ bool acpi_check_dsm(acpi_handle handle, const guid_t *guid, u64 rev, u64 funcs)
 }
 EXPORT_SYMBOL(acpi_check_dsm);
 
+/**
+ * acpi_dev_uid_match - Match device by supplied UID
+ * @adev: ACPI device to match.
+ * @uid2: Unique ID of the device, pass NULL to not check _UID.
+ *
+ * Matches UID in @adev with given @uid2. Absence of @uid2 will be treated as
+ * a match. If user wants to validate @uid2, it should be done before calling
+ * this function. This behaviour is as needed by most of its current users.
+ *
+ * Returns:
+ *  - %true if matches or @uid2 is NULL.
+ *  - %false otherwise.
+ */
+bool acpi_dev_uid_match(struct acpi_device *adev, const char *uid2)
+{
+	const char *uid1 = acpi_device_uid(adev);
+
+	if (!uid2)
+		return true;
+
+	return uid1 && !strcmp(uid1, uid2);
+}
+EXPORT_SYMBOL_GPL(acpi_dev_uid_match);
+
 /**
  * acpi_dev_hid_uid_match - Match device by supplied HID and UID
  * @adev: ACPI device to match.
  * @hid2: Hardware ID of the device.
  * @uid2: Unique ID of the device, pass NULL to not check _UID.
  *
- * Matches HID and UID in @adev with given @hid2 and @uid2.
- * Returns true if matches.
+ * Matches HID and UID in @adev with given @hid2 and @uid2. Absence of @uid2
+ * will be treated as a match. If user wants to validate @uid2, it should be
+ * done before calling this function. This behaviour is as needed by most of
+ * its current users.
+ *
+ * Returns:
+ *  - %true if matches or @uid2 is NULL.
+ *  - %false otherwise.
  */
 bool acpi_dev_hid_uid_match(struct acpi_device *adev,
 			    const char *hid2, const char *uid2)
 {
 	const char *hid1 = acpi_device_hid(adev);
-	const char *uid1 = acpi_device_uid(adev);
 
 	if (strcmp(hid1, hid2))
 		return false;
 
-	if (!uid2)
-		return true;
-
-	return uid1 && !strcmp(uid1, uid2);
+	return acpi_dev_uid_match(adev, uid2);
 }
 EXPORT_SYMBOL(acpi_dev_hid_uid_match);
 
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 254685085c82..d1fe6446ffe0 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -760,6 +760,7 @@ static inline bool acpi_device_can_poweroff(struct acpi_device *adev)
 		adev->power.states[ACPI_STATE_D3_HOT].flags.explicit_set);
 }
 
+bool acpi_dev_uid_match(struct acpi_device *adev, const char *uid2);
 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);
 
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index afd94c9b8b8a..db3a33e19c97 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -787,6 +787,11 @@ static inline bool acpi_dev_present(const char *hid, const char *uid, s64 hrv)
 
 struct acpi_device;
 
+static inline bool acpi_dev_uid_match(struct acpi_device *adev, const char *uid2)
+{
+	return false;
+}
+
 static inline bool
 acpi_dev_hid_uid_match(struct acpi_device *adev, const char *hid2, const char *uid2)
 {
-- 
2.17.1