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linux/drivers/dio/dio-driver.c
Bjorn Helgaas e51c01b084 [PATCH] hp300: fix driver_register() return handling, remove dio_module_init()
Remove the assumption that driver_register() returns the number of devices
bound to the driver.  In fact, it returns zero for success or a negative
error value.

dio_module_init() used the device count to automatically unregister and
unload drivers that found no devices.  That might have worked at one time,
but has been broken for some time because dio_register_driver() returned
either a negative error or a positive count (never zero).  So it could only
unregister on failure, when it's not needed anyway.

This functionality could be resurrected in individual drivers by counting
devices in their .probe() methods.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Philip Blundell <philb@gnu.org>
Cc: Jochen Friedrich <jochen@scram.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-25 08:22:53 -08:00

159 lines
3.7 KiB
C

/*
* DIO Driver Services
*
* Copyright (C) 2004 Jochen Friedrich
*
* Loosely based on drivers/pci/pci-driver.c and drivers/zorro/zorro-driver.c
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive
* for more details.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/dio.h>
/**
* dio_match_device - Tell if a DIO device structure has a matching
* DIO device id structure
* @ids: array of DIO device id structures to search in
* @dev: the DIO device structure to match against
*
* Used by a driver to check whether a DIO device present in the
* system is in its list of supported devices. Returns the matching
* dio_device_id structure or %NULL if there is no match.
*/
const struct dio_device_id *
dio_match_device(const struct dio_device_id *ids,
const struct dio_dev *d)
{
while (ids->id) {
if (ids->id == DIO_WILDCARD)
return ids;
if (DIO_NEEDSSECID(ids->id & 0xff)) {
if (ids->id == d->id)
return ids;
} else {
if ((ids->id & 0xff) == (d->id & 0xff))
return ids;
}
ids++;
}
return NULL;
}
static int dio_device_probe(struct device *dev)
{
int error = 0;
struct dio_driver *drv = to_dio_driver(dev->driver);
struct dio_dev *d = to_dio_dev(dev);
if (!d->driver && drv->probe) {
const struct dio_device_id *id;
id = dio_match_device(drv->id_table, d);
if (id)
error = drv->probe(d, id);
if (error >= 0) {
d->driver = drv;
error = 0;
}
}
return error;
}
/**
* dio_register_driver - register a new DIO driver
* @drv: the driver structure to register
*
* Adds the driver structure to the list of registered drivers
* Returns zero or a negative error value.
*/
int dio_register_driver(struct dio_driver *drv)
{
/* initialize common driver fields */
drv->driver.name = drv->name;
drv->driver.bus = &dio_bus_type;
/* register with core */
return driver_register(&drv->driver);
}
/**
* dio_unregister_driver - unregister a DIO driver
* @drv: the driver structure to unregister
*
* Deletes the driver structure from the list of registered DIO drivers,
* gives it a chance to clean up by calling its remove() function for
* each device it was responsible for, and marks those devices as
* driverless.
*/
void dio_unregister_driver(struct dio_driver *drv)
{
driver_unregister(&drv->driver);
}
/**
* dio_bus_match - Tell if a DIO device structure has a matching DIO
* device id structure
* @ids: array of DIO device id structures to search in
* @dev: the DIO device structure to match against
*
* Used by a driver to check whether a DIO device present in the
* system is in its list of supported devices. Returns the matching
* dio_device_id structure or %NULL if there is no match.
*/
static int dio_bus_match(struct device *dev, struct device_driver *drv)
{
struct dio_dev *d = to_dio_dev(dev);
struct dio_driver *dio_drv = to_dio_driver(drv);
const struct dio_device_id *ids = dio_drv->id_table;
if (!ids)
return 0;
while (ids->id) {
if (ids->id == DIO_WILDCARD)
return 1;
if (DIO_NEEDSSECID(ids->id & 0xff)) {
if (ids->id == d->id)
return 1;
} else {
if ((ids->id & 0xff) == (d->id & 0xff))
return 1;
}
ids++;
}
return 0;
}
struct bus_type dio_bus_type = {
.name = "dio",
.match = dio_bus_match,
.probe = dio_device_probe,
};
static int __init dio_driver_init(void)
{
return bus_register(&dio_bus_type);
}
postcore_initcall(dio_driver_init);
EXPORT_SYMBOL(dio_match_device);
EXPORT_SYMBOL(dio_register_driver);
EXPORT_SYMBOL(dio_unregister_driver);
EXPORT_SYMBOL(dio_dev_driver);
EXPORT_SYMBOL(dio_bus_type);