drivers/uwb/pal.c

   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  */
  29 void uwb_pal_init(struct uwb_pal *pal)
  30 {
  31         INIT_LIST_HEAD(&pal->node);
  32 }
  33 EXPORT_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  */
  41 int 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 }
  69 EXPORT_SYMBOL_GPL(uwb_pal_register);
  70
  71 static 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  */
  94 static 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         put_device(dev);
 101
 102         return (dev != NULL);
 103 }
 104
 105 /**
 106  * uwb_pal_unregister - unregister a UWB PAL
 107  * @pal: the PAL
 108  */
 109 void uwb_pal_unregister(struct uwb_pal *pal)
 110 {
 111         struct uwb_rc *rc = pal->rc;
 112
 113         uwb_radio_stop(pal);
 114
 115         mutex_lock(&rc->uwb_dev.mutex);
 116         list_del(&pal->node);
 117         mutex_unlock(&rc->uwb_dev.mutex);
 118
 119         debugfs_remove(pal->debugfs_dir);
 120
 121         if (pal->device) {
 122                 /* remove link to the PAL in the UWB device's directory. */
 123                 if (uwb_rc_class_device_exists(rc))
 124                         sysfs_remove_link(&rc->uwb_dev.dev.kobj, pal->name);
 125
 126                 /* remove link to uwb_rc in the PAL device's directory. */
 127                 sysfs_remove_link(&pal->device->kobj, "uwb_rc");
 128         }
 129 }
 130 EXPORT_SYMBOL_GPL(uwb_pal_unregister);
 131
 132 /**
 133  * uwb_rc_pal_init - initialize the PAL related parts of a radio controller
 134  * @rc: the radio controller
 135  */
 136 void uwb_rc_pal_init(struct uwb_rc *rc)
 137 {
 138         INIT_LIST_HEAD(&rc->pals);
 139 }