linux-stable/drivers/w1/w1_family.c
Andrew F. Davis de0d6dbdbd w1: Add subsystem kernel public interface
Like other subsystems we should be able to define slave devices outside
of the w1 directory. To do this we move public facing interface
definitions to include/linux/w1.h and rename the internal definition
file to w1_internal.h.

As w1_family.h and w1_int.h contained almost entirely public
driver interface definitions we simply removed these files and
moved the remaining definitions into w1_internal.h.

With this we can now start to move slave devices out of w1/slaves and
into the subsystem based on the function they implement, again like
other drivers.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:54:54 +02:00

139 lines
3 KiB
C

/*
* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*/
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/sched/signal.h>
#include <linux/delay.h>
#include <linux/export.h>
#include "w1_internal.h"
DEFINE_SPINLOCK(w1_flock);
static LIST_HEAD(w1_families);
/**
* w1_register_family() - register a device family driver
* @newf: family to register
*/
int w1_register_family(struct w1_family *newf)
{
struct list_head *ent, *n;
struct w1_family *f;
int ret = 0;
spin_lock(&w1_flock);
list_for_each_safe(ent, n, &w1_families) {
f = list_entry(ent, struct w1_family, family_entry);
if (f->fid == newf->fid) {
ret = -EEXIST;
break;
}
}
if (!ret) {
atomic_set(&newf->refcnt, 0);
list_add_tail(&newf->family_entry, &w1_families);
}
spin_unlock(&w1_flock);
/* check default devices against the new set of drivers */
w1_reconnect_slaves(newf, 1);
return ret;
}
EXPORT_SYMBOL(w1_register_family);
/**
* w1_unregister_family() - unregister a device family driver
* @fent: family to unregister
*/
void w1_unregister_family(struct w1_family *fent)
{
struct list_head *ent, *n;
struct w1_family *f;
spin_lock(&w1_flock);
list_for_each_safe(ent, n, &w1_families) {
f = list_entry(ent, struct w1_family, family_entry);
if (f->fid == fent->fid) {
list_del(&fent->family_entry);
break;
}
}
spin_unlock(&w1_flock);
/* deatch devices using this family code */
w1_reconnect_slaves(fent, 0);
while (atomic_read(&fent->refcnt)) {
pr_info("Waiting for family %u to become free: refcnt=%d.\n",
fent->fid, atomic_read(&fent->refcnt));
if (msleep_interruptible(1000))
flush_signals(current);
}
}
EXPORT_SYMBOL(w1_unregister_family);
/*
* Should be called under w1_flock held.
*/
struct w1_family * w1_family_registered(u8 fid)
{
struct list_head *ent, *n;
struct w1_family *f = NULL;
int ret = 0;
list_for_each_safe(ent, n, &w1_families) {
f = list_entry(ent, struct w1_family, family_entry);
if (f->fid == fid) {
ret = 1;
break;
}
}
return (ret) ? f : NULL;
}
static void __w1_family_put(struct w1_family *f)
{
atomic_dec(&f->refcnt);
}
void w1_family_put(struct w1_family *f)
{
spin_lock(&w1_flock);
__w1_family_put(f);
spin_unlock(&w1_flock);
}
#if 0
void w1_family_get(struct w1_family *f)
{
spin_lock(&w1_flock);
__w1_family_get(f);
spin_unlock(&w1_flock);
}
#endif /* 0 */
void __w1_family_get(struct w1_family *f)
{
smp_mb__before_atomic();
atomic_inc(&f->refcnt);
smp_mb__after_atomic();
}