dmaengine: idxd: add driver register helper

Add helper functions for dsa-driver registration similar to other
bus-types. In particular, do not require dsa-drivers to open-code the
bus, owner, and mod_name fields. Let registration and unregistration
operate on the 'struct idxd_device_driver' instead of the raw /
embedded 'struct device_driver'.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/162637458949.744545.14996726325385482050.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/idxd/idxd.h

@@ -402,6 +402,13 @@ static inline int idxd_wq_refcount(struct idxd_wq *wq)
 	return wq->client_count;
 };
 
+int __must_check __idxd_driver_register(struct idxd_device_driver *idxd_drv,
+					struct module *module, const char *mod_name);
+#define idxd_driver_register(driver) \
+	__idxd_driver_register(driver, THIS_MODULE, KBUILD_MODNAME)
+
+void idxd_driver_unregister(struct idxd_device_driver *idxd_drv);
+
 int idxd_register_bus_type(void);
 void idxd_unregister_bus_type(void);
 int idxd_register_devices(struct idxd_device *idxd);

drivers/dma/idxd/init.c

@@ -855,3 +855,20 @@ static void __exit idxd_exit_module(void)
 	perfmon_exit();
 }
 module_exit(idxd_exit_module);
+
+int __idxd_driver_register(struct idxd_device_driver *idxd_drv, struct module *owner,
+			   const char *mod_name)
+{
+	struct device_driver *drv = &idxd_drv->drv;
+
+	drv->bus = &dsa_bus_type;
+	drv->owner = owner;
+	drv->mod_name = mod_name;
+
+	return driver_register(drv);
+}
+
+void idxd_driver_unregister(struct idxd_device_driver *idxd_drv)
+{
+	driver_unregister(&idxd_drv->drv);
+}

drivers/dma/idxd/sysfs.c

@@ -313,21 +313,18 @@ struct bus_type dsa_bus_type = {
 static struct idxd_device_driver dsa_drv = {
 	.drv = {
 		.name = "dsa",
-		.bus = &dsa_bus_type,
-		.owner = THIS_MODULE,
-		.mod_name = KBUILD_MODNAME,
 	},
 };
 
 /* IDXD generic driver setup */
 int idxd_register_driver(void)
 {
-	return driver_register(&dsa_drv.drv);
+	return idxd_driver_register(&dsa_drv);
 }
 
 void idxd_unregister_driver(void)
 {
-	driver_unregister(&dsa_drv.drv);
+	idxd_driver_unregister(&dsa_drv);
 }
 
 /* IDXD engine attributes */