Revert "parport: daisy: use new parport device model"

This reverts commit 1aec4211204d9463d1fd209eb50453de16254599.

Steven Rostedt reports that it causes a hang at bootup and bisected it
to this commit.

The troigger is apparently a module alias for "parport_lowlevel" that
points to "parport_pc", which causes a hang with

modprobe -q -- parport_lowlevel

blocking forever with a backtrace like this:

wait_for_completion_killable+0x1c/0x28
call_usermodehelper_exec+0xa7/0x108
__request_module+0x351/0x3d8
get_lowlevel_driver+0x28/0x41 [parport]
__parport_register_driver+0x39/0x1f4 [parport]
daisy_drv_init+0x31/0x4f [parport]
parport_bus_init+0x5d/0x7b [parport]
parport_default_proc_register+0x26/0x1000 [parport]
do_one_initcall+0xc2/0x1e0
do_init_module+0x50/0x1d4
load_module+0x1c2e/0x21b3
sys_init_module+0xef/0x117

Supid says:
"Due to the new device model daisy driver will now try to find the
parallel ports while trying to register its driver so that it can bind
with them. Now, since daisy driver is loaded while parport bus is
initialising the list of parport is still empty and it tries to load
the lowlevel driver, which has an alias set to parport_pc, now causes
a deadlock"

But I don't think the daisy driver should be loaded by the parport
initialization in the first place, so let's revert the whole change.

If the daisy driver can just initialize separately on its own (like a
driver should), instead of hooking into the parport init sequence
directly, this issue probably would go away.

Reported-and-bisected-by: Steven Rostedt (VMware) <[e-mail]>
Reported-by: Michal Kubecek <[e-mail]>
Acked-by: Greg Kroah-Hartman <[e-mail]>
Cc: Sudip Mukherjee <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/parport/daisy.c

···
 struct pardevice *parport_open(int devnum, const char *name)
 {
 	struct daisydev *p = topology;
-	struct pardev_cb par_cb;
 	struct parport *port;
 	struct pardevice *dev;
 	int daisy;
 
-	memset(&par_cb, 0, sizeof(par_cb));
 	spin_lock(&topology_lock);
 	while (p && p->devnum != devnum)
 		p = p->next;
···
 	port = parport_get_port(p->port);
 	spin_unlock(&topology_lock);
 
-	dev = parport_register_dev_model(port, name, &par_cb, devnum);
+	dev = parport_register_device(port, name, NULL, NULL, NULL, 0, NULL);
 	parport_put_port(port);
 	if (!dev)
 		return NULL;
···
 
 	kfree(deviceid);
 	return detected;
-}
-
-static int daisy_drv_probe(struct pardevice *par_dev)
-{
-	struct device_driver *drv = par_dev->dev.driver;
-
-	if (strcmp(drv->name, "daisy_drv"))
-		return -ENODEV;
-	if (strcmp(par_dev->name, daisy_dev_name))
-		return -ENODEV;
-
-	return 0;
-}
-
-static struct parport_driver daisy_driver = {
-	.name = "daisy_drv",
-	.probe = daisy_drv_probe,
-	.devmodel = true,
-};
-
-int daisy_drv_init(void)
-{
-	return parport_register_driver(&daisy_driver);
-}
-
-void daisy_drv_exit(void)
-{
-	parport_unregister_driver(&daisy_driver);
 }

drivers/parport/probe.c

···
 ssize_t parport_device_id (int devnum, char *buffer, size_t count)
 {
 	ssize_t retval = -ENXIO;
-	struct pardevice *dev = parport_open(devnum, daisy_dev_name);
+	struct pardevice *dev = parport_open (devnum, "Device ID probe");
 	if (!dev)
 		return -ENXIO;
 

drivers/parport/share.c

···
 
 int parport_bus_init(void)
 {
-	int retval;
-
-	retval = bus_register(&parport_bus_type);
-	if (retval)
-		return retval;
-	daisy_drv_init();
-
-	return 0;
+	return bus_register(&parport_bus_type);
 }
 
 void parport_bus_exit(void)
 {
-	daisy_drv_exit();
 	bus_unregister(&parport_bus_type);
 }
 

include/linux/parport.h

···
 					      void *, size_t, int);
 
 /* IEEE1284.3 functions */
-#define daisy_dev_name "Device ID probe"
 extern int parport_daisy_init (struct parport *port);
 extern void parport_daisy_fini (struct parport *port);
 extern struct pardevice *parport_open (int devnum, const char *name);
···
 extern ssize_t parport_device_id (int devnum, char *buffer, size_t len);
 extern void parport_daisy_deselect_all (struct parport *port);
 extern int parport_daisy_select (struct parport *port, int daisy, int mode);
-
-#ifdef CONFIG_PARPORT_1284
-extern int daisy_drv_init(void);
-extern void daisy_drv_exit(void);
-#else
-static inline int daisy_drv_init(void)
-{
-	return 0;
-}
-
-static inline void daisy_drv_exit(void) {}
-#endif
 
 /* Lowlevel drivers _can_ call this support function to handle irqs.  */
 static inline void parport_generic_irq(struct parport *port)