2 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
15 #include <linux/spinlock.h>
16 #include <linux/list.h>
17 #include <linux/sched/signal.h>
18 #include <linux/delay.h>
19 #include <linux/export.h>
21 #include "w1_family.h"
24 DEFINE_SPINLOCK(w1_flock);
25 static LIST_HEAD(w1_families);
28 * w1_register_family() - register a device family driver
29 * @newf: family to register
31 int w1_register_family(struct w1_family *newf)
33 struct list_head *ent, *n;
38 list_for_each_safe(ent, n, &w1_families) {
39 f = list_entry(ent, struct w1_family, family_entry);
41 if (f->fid == newf->fid) {
48 atomic_set(&newf->refcnt, 0);
49 list_add_tail(&newf->family_entry, &w1_families);
51 spin_unlock(&w1_flock);
53 /* check default devices against the new set of drivers */
54 w1_reconnect_slaves(newf, 1);
60 * w1_unregister_family() - unregister a device family driver
61 * @fent: family to unregister
63 void w1_unregister_family(struct w1_family *fent)
65 struct list_head *ent, *n;
69 list_for_each_safe(ent, n, &w1_families) {
70 f = list_entry(ent, struct w1_family, family_entry);
72 if (f->fid == fent->fid) {
73 list_del(&fent->family_entry);
77 spin_unlock(&w1_flock);
79 /* deatch devices using this family code */
80 w1_reconnect_slaves(fent, 0);
82 while (atomic_read(&fent->refcnt)) {
83 pr_info("Waiting for family %u to become free: refcnt=%d.\n",
84 fent->fid, atomic_read(&fent->refcnt));
86 if (msleep_interruptible(1000))
87 flush_signals(current);
92 * Should be called under w1_flock held.
94 struct w1_family * w1_family_registered(u8 fid)
96 struct list_head *ent, *n;
97 struct w1_family *f = NULL;
100 list_for_each_safe(ent, n, &w1_families) {
101 f = list_entry(ent, struct w1_family, family_entry);
109 return (ret) ? f : NULL;
112 static void __w1_family_put(struct w1_family *f)
114 atomic_dec(&f->refcnt);
117 void w1_family_put(struct w1_family *f)
119 spin_lock(&w1_flock);
121 spin_unlock(&w1_flock);
125 void w1_family_get(struct w1_family *f)
127 spin_lock(&w1_flock);
129 spin_unlock(&w1_flock);
133 void __w1_family_get(struct w1_family *f)
135 smp_mb__before_atomic();
136 atomic_inc(&f->refcnt);
137 smp_mb__after_atomic();
140 EXPORT_SYMBOL(w1_unregister_family);
141 EXPORT_SYMBOL(w1_register_family);