linux/drivers/uwb/pal.c
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   1/*
   2 * UWB PAL support.
   3 *
   4 * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License version
   8 * 2 as published by the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18#include <linux/kernel.h>
  19#include <linux/debugfs.h>
  20#include <linux/uwb.h>
  21#include <linux/export.h>
  22
  23#include "uwb-internal.h"
  24
  25/**
  26 * uwb_pal_init - initialize a UWB PAL
  27 * @pal: the PAL to initialize
  28 */
  29void uwb_pal_init(struct uwb_pal *pal)
  30{
  31        INIT_LIST_HEAD(&pal->node);
  32}
  33EXPORT_SYMBOL_GPL(uwb_pal_init);
  34
  35/**
  36 * uwb_pal_register - register a UWB PAL
  37 * @pal: the PAL
  38 *
  39 * The PAL must be initialized with uwb_pal_init().
  40 */
  41int uwb_pal_register(struct uwb_pal *pal)
  42{
  43        struct uwb_rc *rc = pal->rc;
  44        int ret;
  45
  46        if (pal->device) {
  47                /* create a link to the uwb_rc in the PAL device's directory. */
  48                ret = sysfs_create_link(&pal->device->kobj,
  49                                        &rc->uwb_dev.dev.kobj, "uwb_rc");
  50                if (ret < 0)
  51                        return ret;
  52                /* create a link to the PAL in the UWB device's directory. */
  53                ret = sysfs_create_link(&rc->uwb_dev.dev.kobj,
  54                                        &pal->device->kobj, pal->name);
  55                if (ret < 0) {
  56                        sysfs_remove_link(&pal->device->kobj, "uwb_rc");
  57                        return ret;
  58                }
  59        }
  60
  61        pal->debugfs_dir = uwb_dbg_create_pal_dir(pal);
  62
  63        mutex_lock(&rc->uwb_dev.mutex);
  64        list_add(&pal->node, &rc->pals);
  65        mutex_unlock(&rc->uwb_dev.mutex);
  66
  67        return 0;
  68}
  69EXPORT_SYMBOL_GPL(uwb_pal_register);
  70
  71static int find_rc(struct device *dev, const void *data)
  72{
  73        const struct uwb_rc *target_rc = data;
  74        struct uwb_rc *rc = dev_get_drvdata(dev);
  75
  76        if (rc == NULL) {
  77                WARN_ON(1);
  78                return 0;
  79        }
  80        if (rc == target_rc) {
  81                if (rc->ready == 0)
  82                        return 0;
  83                else
  84                        return 1;
  85        }
  86        return 0;
  87}
  88
  89/**
  90 * Given a radio controller descriptor see if it is registered.
  91 *
  92 * @returns false if the rc does not exist or is quiescing; true otherwise.
  93 */
  94static bool uwb_rc_class_device_exists(struct uwb_rc *target_rc)
  95{
  96        struct device *dev;
  97
  98        dev = class_find_device(&uwb_rc_class, NULL, target_rc, find_rc);
  99
 100        return (dev != NULL);
 101}
 102
 103/**
 104 * uwb_pal_unregister - unregister a UWB PAL
 105 * @pal: the PAL
 106 */
 107void uwb_pal_unregister(struct uwb_pal *pal)
 108{
 109        struct uwb_rc *rc = pal->rc;
 110
 111        uwb_radio_stop(pal);
 112
 113        mutex_lock(&rc->uwb_dev.mutex);
 114        list_del(&pal->node);
 115        mutex_unlock(&rc->uwb_dev.mutex);
 116
 117        debugfs_remove(pal->debugfs_dir);
 118
 119        if (pal->device) {
 120                /* remove link to the PAL in the UWB device's directory. */
 121                if (uwb_rc_class_device_exists(rc))
 122                        sysfs_remove_link(&rc->uwb_dev.dev.kobj, pal->name);
 123
 124                /* remove link to uwb_rc in the PAL device's directory. */
 125                sysfs_remove_link(&pal->device->kobj, "uwb_rc");
 126        }
 127}
 128EXPORT_SYMBOL_GPL(uwb_pal_unregister);
 129
 130/**
 131 * uwb_rc_pal_init - initialize the PAL related parts of a radio controller
 132 * @rc: the radio controller
 133 */
 134void uwb_rc_pal_init(struct uwb_rc *rc)
 135{
 136        INIT_LIST_HEAD(&rc->pals);
 137}
 138
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