[PATCH] driver core: add bus_find_device & driver_find_device functions
Add bus_find_device() and driver_find_device() which allow searching for a
device in the bus's resp. the driver's klist and obtain a reference on it.
Signed-off-by: Cornelia Huck <cohuck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 1b64588..291c595 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -56,6 +56,41 @@
/**
+ * driver_find_device - device iterator for locating a particular device.
+ * @driver: The device's driver
+ * @start: Device to begin with
+ * @data: Data to pass to match function
+ * @match: Callback function to check device
+ *
+ * This is similar to the driver_for_each_device() function above, but
+ * it returns a reference to a device that is 'found' for later use, as
+ * determined by the @match callback.
+ *
+ * The callback should return 0 if the device doesn't match and non-zero
+ * if it does. If the callback returns non-zero, this function will
+ * return to the caller and not iterate over any more devices.
+ */
+struct device * driver_find_device(struct device_driver *drv,
+ struct device * start, void * data,
+ int (*match)(struct device *, void *))
+{
+ struct klist_iter i;
+ struct device *dev;
+
+ if (!drv)
+ return NULL;
+
+ klist_iter_init_node(&drv->klist_devices, &i,
+ (start ? &start->knode_driver : NULL));
+ while ((dev = next_device(&i)))
+ if (match(dev, data) && get_device(dev))
+ break;
+ klist_iter_exit(&i);
+ return dev;
+}
+EXPORT_SYMBOL_GPL(driver_find_device);
+
+/**
* driver_create_file - create sysfs file for driver.
* @drv: driver.
* @attr: driver attribute descriptor.