staging: comedi: Add helper macro for comedi usb driver boilerplate

Introduce the module_comedi_usb_driver macro, and the
associated register/unregister functions, which is a
convenience macro for comedi usb driver modules similar
to module_platform_driver. It is intended to be used by
drivers where the init/exit section does nothing but
register/unregister the comedi driver and associated usb
driver. By using this macro it is possible to eliminate
a few lines of boilerplate code per comedi usb driver.

Also, when registering the usb driver check for failure
and unregister the comedi driver.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/comedidev.h b/drivers/staging/comedi/comedidev.h
index 92a1199..f7f023c 100644 (file)
--- a/drivers/staging/comedi/comedidev.h
+++ b/drivers/staging/comedi/comedidev.h
@@ -329,6 +329,25 @@ void comedi_pci_driver_unregister(struct comedi_driver *, struct pci_driver *);
        module_driver(__comedi_driver, comedi_pci_driver_register, \
                        comedi_pci_driver_unregister, &(__pci_driver))
 
+struct usb_driver;
+
+int comedi_usb_driver_register(struct comedi_driver *, struct usb_driver *);
+void comedi_usb_driver_unregister(struct comedi_driver *, struct usb_driver *);
+
+/**
+ * module_comedi_usb_driver() - Helper macro for registering a comedi USB driver
+ * @__comedi_driver: comedi_driver struct
+ * @__usb_driver: usb_driver struct
+ *
+ * Helper macro for comedi USB drivers which do not do anything special
+ * in module init/exit. This eliminates a lot of boilerplate. Each
+ * module may only use this macro once, and calling it replaces
+ * module_init() and module_exit()
+ */
+#define module_comedi_usb_driver(__comedi_driver, __usb_driver) \
+       module_driver(__comedi_driver, comedi_usb_driver_register, \
+                       comedi_usb_driver_unregister, &(__usb_driver))
+
 void init_polling(void);
 void cleanup_polling(void);
 void start_polling(struct comedi_device *);

diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
index 3a82950..1c3d638 100644 (file)
--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -1016,3 +1016,30 @@ void comedi_usb_auto_unconfig(struct usb_interface *intf)
        comedi_auto_unconfig(&intf->dev);
 }
 EXPORT_SYMBOL_GPL(comedi_usb_auto_unconfig);
+
+int comedi_usb_driver_register(struct comedi_driver *comedi_driver,
+               struct usb_driver *usb_driver)
+{
+       int ret;
+
+       ret = comedi_driver_register(comedi_driver);
+       if (ret < 0)
+               return ret;
+
+       ret = usb_register(usb_driver);
+       if (ret < 0) {
+               comedi_driver_unregister(comedi_driver);
+               return ret;
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(comedi_usb_driver_register);
+
+void comedi_usb_driver_unregister(struct comedi_driver *comedi_driver,
+               struct usb_driver *usb_driver)
+{
+       usb_deregister(usb_driver);
+       comedi_driver_unregister(comedi_driver);
+}
+EXPORT_SYMBOL_GPL(comedi_usb_driver_unregister);