drivers: Introduce device lookup variants by name

Add a helper to match the device name for device lookup. Also
reuse this generic exported helper for the existing bus_find_device_by_name().
and add similar variants for driver/class.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: linux-leds@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-wpan@vger.kernel.org
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20190723221838.12024-2-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/bus.c

@@ -342,30 +342,6 @@ struct device *bus_find_device(struct bus_type *bus,
 }
 EXPORT_SYMBOL_GPL(bus_find_device);
 
-static int match_name(struct device *dev, const void *data)
-{
-	const char *name = data;
-
-	return sysfs_streq(name, dev_name(dev));
-}
-
-/**
- * bus_find_device_by_name - device iterator for locating a particular device of a specific name
- * @bus: bus type
- * @start: Device to begin with
- * @name: name of the device to match
- *
- * This is similar to the bus_find_device() function above, but it handles
- * searching by a name automatically, no need to write another strcmp matching
- * function.
- */
-struct device *bus_find_device_by_name(struct bus_type *bus,
-				       struct device *start, const char *name)
-{
-	return bus_find_device(bus, start, (void *)name, match_name);
-}
-EXPORT_SYMBOL_GPL(bus_find_device_by_name);
-
 /**
  * subsys_find_device_by_id - find a device with a specific enumeration number
  * @subsys: subsystem

drivers/base/core.c

@@ -3357,6 +3357,12 @@ void device_set_of_node_from_dev(struct device *dev, const struct device *dev2)
 }
 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev);
 
+int device_match_name(struct device *dev, const void *name)
+{
+	return sysfs_streq(dev_name(dev), name);
+}
+EXPORT_SYMBOL_GPL(device_match_name);
+
 int device_match_of_node(struct device *dev, const void *np)
 {
 	return dev->of_node == np;

drivers/hwtracing/stm/core.c

@@ -89,13 +89,6 @@ static struct class stm_class = {
 	.dev_groups	= stm_groups,
 };
 
-static int stm_dev_match(struct device *dev, const void *data)
-{
-	const char *name = data;
-
-	return sysfs_streq(name, dev_name(dev));
-}
-
 /**
  * stm_find_device() - find stm device by name
  * @buf:	character buffer containing the name
@@ -116,7 +109,7 @@ struct stm_device *stm_find_device(const char *buf)
 	if (!stm_core_up)
 		return NULL;
 
-	dev = class_find_device(&stm_class, NULL, buf, stm_dev_match);
+	dev = class_find_device_by_name(&stm_class, buf);
 	if (!dev)
 		return NULL;
 

drivers/leds/led-class.c

@@ -213,13 +213,6 @@ static int led_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 
-static int match_name(struct device *dev, const void *data)
-{
-	if (!dev_name(dev))
-		return 0;
-	return !strcmp(dev_name(dev), (char *)data);
-}
-
 static int led_classdev_next_name(const char *init_name, char *name,
 				  size_t len)
 {
@@ -230,7 +223,7 @@ static int led_classdev_next_name(const char *init_name, char *name,
 	strlcpy(name, init_name, len);
 
 	while ((ret < len) &&
-	       (dev = class_find_device(leds_class, NULL, name, match_name))) {
+	       (dev = class_find_device_by_name(leds_class, name))) {
 		put_device(dev);
 		ret = snprintf(name, len, "%s_%u", init_name, ++i);
 	}

drivers/rtc/interface.c

@@ -663,21 +663,12 @@ void rtc_update_irq(struct rtc_device *rtc,
 }
 EXPORT_SYMBOL_GPL(rtc_update_irq);
 
-static int __rtc_match(struct device *dev, const void *data)
-{
-	const char *name = data;
-
-	if (strcmp(dev_name(dev), name) == 0)
-		return 1;
-	return 0;
-}
-
 struct rtc_device *rtc_class_open(const char *name)
 {
 	struct device *dev;
 	struct rtc_device *rtc = NULL;
 
-	dev = class_find_device(rtc_class, NULL, name, __rtc_match);
+	dev = class_find_device_by_name(rtc_class, name);
 	if (dev)
 		rtc = to_rtc_device(dev);
 

drivers/s390/cio/ccwgroup.c

@@ -608,13 +608,6 @@ void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 }
 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 
-static int __ccwgroupdev_check_busid(struct device *dev, const void *id)
-{
-	const char *bus_id = id;
-
-	return (strcmp(bus_id, dev_name(dev)) == 0);
-}
-
 /**
  * get_ccwgroupdev_by_busid() - obtain device from a bus id
  * @gdrv: driver the device is owned by
@@ -631,8 +624,7 @@ struct ccwgroup_device *get_ccwgroupdev_by_busid(struct ccwgroup_driver *gdrv,
 {
 	struct device *dev;
 
-	dev = driver_find_device(&gdrv->driver, NULL, bus_id,
-				 __ccwgroupdev_check_busid);
+	dev = driver_find_device_by_name(&gdrv->driver, bus_id);
 
 	return dev ? to_ccwgroupdev(dev) : NULL;
 }

drivers/s390/cio/device.c

@@ -1695,18 +1695,6 @@ int ccw_device_force_console(struct ccw_device *cdev)
 EXPORT_SYMBOL_GPL(ccw_device_force_console);
 #endif
 
-/*
- * get ccw_device matching the busid, but only if owned by cdrv
- */
-static int
-__ccwdev_check_busid(struct device *dev, const void *id)
-{
-	const char *bus_id = id;
-
-	return (strcmp(bus_id, dev_name(dev)) == 0);
-}
-
-
 /**
  * get_ccwdev_by_busid() - obtain device from a bus id
  * @cdrv: driver the device is owned by
@@ -1723,8 +1711,7 @@ struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
 {
 	struct device *dev;
 
-	dev = driver_find_device(&cdrv->driver, NULL, (void *)bus_id,
-				 __ccwdev_check_busid);
+	dev = driver_find_device_by_name(&cdrv->driver, bus_id);
 
 	return dev ? to_ccwdev(dev) : NULL;
 }

drivers/s390/crypto/zcrypt_api.c

@@ -133,12 +133,6 @@ struct zcdn_device {
 static int zcdn_create(const char *name);
 static int zcdn_destroy(const char *name);
 
-/* helper function, matches the name for find_zcdndev_by_name() */
-static int __match_zcdn_name(struct device *dev, const void *data)
-{
-	return strcmp(dev_name(dev), (const char *)data) == 0;
-}
-
 /* helper function, matches the devt value for find_zcdndev_by_devt() */
 static int __match_zcdn_devt(struct device *dev, const void *data)
 {
@@ -152,10 +146,7 @@ static int __match_zcdn_devt(struct device *dev, const void *data)
  */
 static inline struct zcdn_device *find_zcdndev_by_name(const char *name)
 {
-	struct device *dev =
-		class_find_device(zcrypt_class, NULL,
-				  (void *) name,
-				  __match_zcdn_name);
+	struct device *dev = class_find_device_by_name(zcrypt_class, name);
 
 	return dev ? to_zcdn_dev(dev) : NULL;
 }

drivers/usb/roles/class.c

@@ -90,11 +90,6 @@ static int switch_fwnode_match(struct device *dev, const void *fwnode)
 	return dev_fwnode(dev) == fwnode;
 }
 
-static int switch_name_match(struct device *dev, const void *name)
-{
-	return !strcmp((const char *)name, dev_name(dev));
-}
-
 static void *usb_role_switch_match(struct device_connection *con, int ep,
 				   void *data)
 {
@@ -107,8 +102,7 @@ static void *usb_role_switch_match(struct device_connection *con, int ep,
 		dev = class_find_device(role_class, NULL, con->fwnode,
 					switch_fwnode_match);
 	} else {
-		dev = class_find_device(role_class, NULL, con->endpoint[ep],
-					switch_name_match);
+		dev = class_find_device_by_name(role_class, con->endpoint[ep]);
 	}
 
 	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);

drivers/usb/typec/class.c

@@ -210,11 +210,6 @@ static int typec_port_fwnode_match(struct device *dev, const void *fwnode)
 	return dev_fwnode(dev) == fwnode;
 }
 
-static int typec_port_name_match(struct device *dev, const void *name)
-{
-	return !strcmp((const char *)name, dev_name(dev));
-}
-
 static void *typec_port_match(struct device_connection *con, int ep, void *data)
 {
 	struct device *dev;
@@ -227,8 +222,7 @@ static void *typec_port_match(struct device_connection *con, int ep, void *data)
 		return class_find_device(typec_class, NULL, con->fwnode,
 					 typec_port_fwnode_match);
 
-	dev = class_find_device(typec_class, NULL, con->endpoint[ep],
-				typec_port_name_match);
+	dev = class_find_device_by_name(typec_class, con->endpoint[ep]);
 
 	return dev ? dev : ERR_PTR(-EPROBE_DEFER);
 }

include/linux/device.h

@@ -164,16 +164,28 @@ void subsys_dev_iter_init(struct subsys_dev_iter *iter,
 struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter);
 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 bus_for_each_dev(struct bus_type *bus, struct device *start, void *data,
 		     int (*fn)(struct device *dev, void *data));
 struct device *bus_find_device(struct bus_type *bus, struct device *start,
 			       const void *data,
 			       int (*match)(struct device *dev, const void *data));
-struct device *bus_find_device_by_name(struct bus_type *bus,
-				       struct device *start,
-				       const char *name);
+/**
+ * bus_find_device_by_name - device iterator for locating a particular device
+ * of a specific name.
+ * @bus: bus type
+ * @start: Device to begin with
+ * @name: name of the device to match
+ */
+static inline struct device *bus_find_device_by_name(struct bus_type *bus,
+						     struct device *start,
+						     const char *name)
+{
+	return bus_find_device(bus, start, name, device_match_name);
+}
+
 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,
@@ -342,6 +354,18 @@ struct device *driver_find_device(struct device_driver *drv,
 				  struct device *start, const void *data,
 				  int (*match)(struct device *dev, const void *data));
 
+/**
+ * driver_find_device_by_name - device iterator for locating a particular device
+ * of a specific name.
+ * @driver: the driver we're iterating
+ * @name: name of the device to match
+ */
+static inline struct device *driver_find_device_by_name(struct device_driver *drv,
+							const char *name)
+{
+	return driver_find_device(drv, NULL, name, device_match_name);
+}
+
 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);
@@ -471,6 +495,18 @@ extern struct device *class_find_device(struct class *class,
 					struct device *start, const void *data,
 					int (*match)(struct device *, const void *));
 
+/**
+ * class_find_device_by_name - device iterator for locating a particular device
+ * of a specific name.
+ * @class: class type
+ * @name: name of the device to match
+ */
+static inline struct device *class_find_device_by_name(struct class *class,
+						       const char *name)
+{
+	return class_find_device(class, NULL, name, device_match_name);
+}
+
 struct class_attribute {
 	struct attribute attr;
 	ssize_t (*show)(struct class *class, struct class_attribute *attr,

net/ieee802154/core.c

@@ -23,19 +23,14 @@
 LIST_HEAD(cfg802154_rdev_list);
 int cfg802154_rdev_list_generation;
 
-static int wpan_phy_match(struct device *dev, const void *data)
-{
-	return !strcmp(dev_name(dev), (const char *)data);
-}
-
 struct wpan_phy *wpan_phy_find(const char *str)
 {
 	struct device *dev;
 
 	if (WARN_ON(!str))
 		return NULL;
 
-	dev = class_find_device(&wpan_phy_class, NULL, str, wpan_phy_match);
+	dev = class_find_device_by_name(&wpan_phy_class, str);
 	if (!dev)
 		return NULL;