alistair23-linux/drivers/uwb/pal.c
Thomas Pugliese fbbde074ab UWB: fix sysfs warning on HWA device unplug.
In the disconnect routine for the hwa_hc interface, it calls
uwb_pal_unregister to unregister itself from the UWB subsystem.  This
function attempts to clean up the link to the host controller directory in
the device's UWB radio control interface directory.  If the disconnect
routine for the radio control interface has already run, the uwb directory
will be gone so the call to sysfs_remove_link generates a warning.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-08-12 15:41:09 -07:00

138 lines
3.2 KiB
C

/*
* UWB PAL support.
*
* Copyright (C) 2008 Cambridge Silicon Radio Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/kernel.h>
#include <linux/debugfs.h>
#include <linux/uwb.h>
#include <linux/export.h>
#include "uwb-internal.h"
/**
* uwb_pal_init - initialize a UWB PAL
* @pal: the PAL to initialize
*/
void uwb_pal_init(struct uwb_pal *pal)
{
INIT_LIST_HEAD(&pal->node);
}
EXPORT_SYMBOL_GPL(uwb_pal_init);
/**
* uwb_pal_register - register a UWB PAL
* @pal: the PAL
*
* The PAL must be initialized with uwb_pal_init().
*/
int uwb_pal_register(struct uwb_pal *pal)
{
struct uwb_rc *rc = pal->rc;
int ret;
if (pal->device) {
/* create a link to the uwb_rc in the PAL device's directory. */
ret = sysfs_create_link(&pal->device->kobj,
&rc->uwb_dev.dev.kobj, "uwb_rc");
if (ret < 0)
return ret;
/* create a link to the PAL in the UWB device's directory. */
ret = sysfs_create_link(&rc->uwb_dev.dev.kobj,
&pal->device->kobj, pal->name);
if (ret < 0) {
sysfs_remove_link(&pal->device->kobj, "uwb_rc");
return ret;
}
}
pal->debugfs_dir = uwb_dbg_create_pal_dir(pal);
mutex_lock(&rc->uwb_dev.mutex);
list_add(&pal->node, &rc->pals);
mutex_unlock(&rc->uwb_dev.mutex);
return 0;
}
EXPORT_SYMBOL_GPL(uwb_pal_register);
static int find_rc(struct device *dev, const void *data)
{
const struct uwb_rc *target_rc = data;
struct uwb_rc *rc = dev_get_drvdata(dev);
if (rc == NULL) {
WARN_ON(1);
return 0;
}
if (rc == target_rc) {
if (rc->ready == 0)
return 0;
else
return 1;
}
return 0;
}
/**
* Given a radio controller descriptor see if it is registered.
*
* @returns false if the rc does not exist or is quiescing; true otherwise.
*/
static bool uwb_rc_class_device_exists(struct uwb_rc *target_rc)
{
struct device *dev;
dev = class_find_device(&uwb_rc_class, NULL, target_rc, find_rc);
return (dev != NULL);
}
/**
* uwb_pal_unregister - unregister a UWB PAL
* @pal: the PAL
*/
void uwb_pal_unregister(struct uwb_pal *pal)
{
struct uwb_rc *rc = pal->rc;
uwb_radio_stop(pal);
mutex_lock(&rc->uwb_dev.mutex);
list_del(&pal->node);
mutex_unlock(&rc->uwb_dev.mutex);
debugfs_remove(pal->debugfs_dir);
if (pal->device) {
/* remove link to the PAL in the UWB device's directory. */
if (uwb_rc_class_device_exists(rc))
sysfs_remove_link(&rc->uwb_dev.dev.kobj, pal->name);
/* remove link to uwb_rc in the PAL device's directory. */
sysfs_remove_link(&pal->device->kobj, "uwb_rc");
}
}
EXPORT_SYMBOL_GPL(uwb_pal_unregister);
/**
* uwb_rc_pal_init - initialize the PAL related parts of a radio controller
* @rc: the radio controller
*/
void uwb_rc_pal_init(struct uwb_rc *rc)
{
INIT_LIST_HEAD(&rc->pals);
}