drivers: Introduce device lookup variants by device type

Add a helper to match a device by its type and provide wrappers
for {bus/class/driver}_find_device() APIs.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-usb@vger.kernel.org
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190723221838.12024-5-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index 7133fc1c285d..93b2f55ef44e 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -167,6 +167,7 @@ void subsys_dev_iter_exit(struct subsys_dev_iter *iter);
 int device_match_name(struct device *dev, const void *name);
 int device_match_of_node(struct device *dev, const void *np);
 int device_match_fwnode(struct device *dev, const void *fwnode);
+int device_match_devt(struct device *dev, const void *pdevt);
 
 int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data,
 		     int (*fn)(struct device *dev, void *data));
@@ -211,6 +212,18 @@ bus_find_device_by_fwnode(struct bus_type *bus, const struct fwnode_handle *fwno
 	return bus_find_device(bus, NULL, fwnode, device_match_fwnode);
 }
 
+/**
+ * bus_find_device_by_devt : device iterator for locating a particular device
+ * matching the device type.
+ * @bus: bus type
+ * @devt: device type of the device to match.
+ */
+static inline struct device *bus_find_device_by_devt(struct bus_type *bus,
+						     dev_t devt)
+{
+	return bus_find_device(bus, NULL, &devt, device_match_devt);
+}
+
 struct device *subsys_find_device_by_id(struct bus_type *bus, unsigned int id,
 					struct device *hint);
 int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
@@ -417,6 +430,18 @@ driver_find_device_by_fwnode(struct device_driver *drv,
 	return driver_find_device(drv, NULL, fwnode, device_match_fwnode);
 }
 
+/**
+ * driver_find_device_by_devt- device iterator for locating a particular device
+ * by devt.
+ * @driver: the driver we're iterating
+ * @devt: devt pointer to match.
+ */
+static inline struct device *driver_find_device_by_devt(struct device_driver *drv,
+							dev_t devt)
+{
+	return driver_find_device(drv, NULL, &devt, device_match_devt);
+}
+
 void driver_deferred_probe_add(struct device *dev);
 int driver_deferred_probe_check_state(struct device *dev);
 int driver_deferred_probe_check_state_continue(struct device *dev);
@@ -583,6 +608,18 @@ class_find_device_by_fwnode(struct class *class,
 	return class_find_device(class, NULL, fwnode, device_match_fwnode);
 }
 
+/**
+ * class_find_device_by_devt : device iterator for locating a particular device
+ * matching the device type.
+ * @class: class type
+ * @devt: device type of the device to match.
+ */
+static inline struct device *class_find_device_by_devt(struct class *class,
+						       dev_t devt)
+{
+	return class_find_device(class, NULL, &devt, device_match_devt);
+}
+
 struct class_attribute {
 	struct attribute attr;
 	ssize_t (*show)(struct class *class, struct class_attribute *attr,