linux/drivers/w1/w1_int.c

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/*
* w1_int.c
*
* Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
*
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include "w1.h"
#include "w1_log.h"
#include "w1_netlink.h"
#include "w1_int.h"
static int w1_search_count = -1; /* Default is continual scan */
module_param_named(search_count, w1_search_count, int, 0);
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 07:04:42 +02:00
static int w1_enable_pullup = 1;
module_param_named(enable_pullup, w1_enable_pullup, int, 0);
static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
struct device_driver *driver,
struct device *device)
{
struct w1_master *dev;
int err;
/*
* We are in process context(kernel thread), so can sleep.
*/
2007-07-19 10:49:03 +02:00
dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL);
if (!dev) {
printk(KERN_ERR
"Failed to allocate %zd bytes for new w1 device.\n",
sizeof(struct w1_master));
return NULL;
}
dev->bus_master = (struct w1_bus_master *)(dev + 1);
dev->owner = THIS_MODULE;
dev->max_slave_count = slave_count;
dev->slave_count = 0;
dev->attempts = 0;
dev->initialized = 0;
dev->id = id;
dev->slave_ttl = slave_ttl;
dev->search_count = w1_search_count;
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 07:04:42 +02:00
dev->enable_pullup = w1_enable_pullup;
/* 1 for w1_process to decrement
* 1 for __w1_remove_master_device to decrement
*/
atomic_set(&dev->refcnt, 2);
INIT_LIST_HEAD(&dev->slist);
mutex_init(&dev->mutex);
memcpy(&dev->dev, device, sizeof(struct device));
dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
dev->driver = driver;
dev->seq = 1;
err = device_register(&dev->dev);
if (err) {
printk(KERN_ERR "Failed to register master device. err=%d\n", err);
memset(dev, 0, sizeof(struct w1_master));
kfree(dev);
dev = NULL;
}
return dev;
}
static void w1_free_dev(struct w1_master *dev)
{
device_unregister(&dev->dev);
}
int w1_add_master_device(struct w1_bus_master *master)
{
struct w1_master *dev, *entry;
int retval = 0;
struct w1_netlink_msg msg;
int id, found;
/* validate minimum functionality */
if (!(master->touch_bit && master->reset_bus) &&
!(master->write_bit && master->read_bit) &&
!(master->write_byte && master->read_byte && master->reset_bus)) {
printk(KERN_ERR "w1_add_master_device: invalid function set\n");
return(-EINVAL);
}
W1: feature, enable hardware strong pullup Add a strong pullup option to the w1 system. This supplies extra power for parasite powered devices. There is a w1_master_pullup sysfs entry and enable_pullup module parameter to enable or disable the strong pullup. The one wire bus requires at a minimum one wire and ground. The common wire is used for sending and receiving data as well as supplying power to devices that are parasite powered of which temperature sensors can be one example. The bus must be idle and left high while a temperature conversion is in progress, in addition the normal pullup resister on larger networks or even higher temperatures might not supply enough power. The pullup resister can't provide too much pullup current, because devices need to pull the bus down to write a value. This enables the strong pullup for supported hardware, which can supply more current when requested. Unsupported hardware will just delay with the bus high. The hardware USB 2490 one wire bus master has a bit on some commands which will enable the strong pullup as soon as the command finishes executing. To use strong pullup, call the new w1_next_pullup function to register the duration. The next write command will call set_pullup before sending the data, and reset the duration to zero once it returns. Switched from simple_strtol to strict_strtol. Signed-off-by: David Fries <david@fries.net> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 07:04:42 +02:00
/* While it would be electrically possible to make a device that
* generated a strong pullup in bit bang mode, only hardare that
* controls 1-wire time frames are even expected to support a strong
* pullup. w1_io.c would need to support calling set_pullup before
* the last write_bit operation of a w1_write_8 which it currently
* doesn't.
*/
if (!master->write_byte && !master->touch_bit && master->set_pullup) {
printk(KERN_ERR "w1_add_master_device: set_pullup requires "
"write_byte or touch_bit, disabling\n");
master->set_pullup = NULL;
}
/* Lock until the device is added (or not) to w1_masters. */
mutex_lock(&w1_mlock);
/* Search for the first available id (starting at 1). */
id = 0;
do {
++id;
found = 0;
list_for_each_entry(entry, &w1_masters, w1_master_entry) {
if (entry->id == id) {
found = 1;
break;
}
}
} while (found);
dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
&w1_master_driver, &w1_master_device);
if (!dev) {
mutex_unlock(&w1_mlock);
return -ENOMEM;
}
retval = w1_create_master_attributes(dev);
if (retval) {
mutex_unlock(&w1_mlock);
goto err_out_free_dev;
}
memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
dev->initialized = 1;
dev->thread = kthread_run(&w1_process, dev, "%s", dev->name);
if (IS_ERR(dev->thread)) {
retval = PTR_ERR(dev->thread);
dev_err(&dev->dev,
"Failed to create new kernel thread. err=%d\n",
retval);
mutex_unlock(&w1_mlock);
goto err_out_rm_attr;
}
list_add(&dev->w1_master_entry, &w1_masters);
mutex_unlock(&w1_mlock);
memset(&msg, 0, sizeof(msg));
msg.id.mst.id = dev->id;
msg.type = W1_MASTER_ADD;
w1_netlink_send(dev, &msg);
return 0;
#if 0 /* Thread cleanup code, not required currently. */
err_out_kill_thread:
kthread_stop(dev->thread);
#endif
err_out_rm_attr:
w1_destroy_master_attributes(dev);
err_out_free_dev:
w1_free_dev(dev);
return retval;
}
void __w1_remove_master_device(struct w1_master *dev)
{
struct w1_netlink_msg msg;
struct w1_slave *sl, *sln;
kthread_stop(dev->thread);
mutex_lock(&w1_mlock);
list_del(&dev->w1_master_entry);
mutex_unlock(&w1_mlock);
mutex_lock(&dev->mutex);
list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry)
w1_slave_detach(sl);
w1_destroy_master_attributes(dev);
mutex_unlock(&dev->mutex);
atomic_dec(&dev->refcnt);
while (atomic_read(&dev->refcnt)) {
dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n",
dev->name, atomic_read(&dev->refcnt));
if (msleep_interruptible(1000))
flush_signals(current);
}
memset(&msg, 0, sizeof(msg));
msg.id.mst.id = dev->id;
msg.type = W1_MASTER_REMOVE;
w1_netlink_send(dev, &msg);
w1_free_dev(dev);
}
void w1_remove_master_device(struct w1_bus_master *bm)
{
struct w1_master *dev, *found = NULL;
list_for_each_entry(dev, &w1_masters, w1_master_entry) {
if (!dev->initialized)
continue;
if (dev->bus_master->data == bm->data) {
found = dev;
break;
}
}
if (!found) {
printk(KERN_ERR "Device doesn't exist.\n");
return;
}
__w1_remove_master_device(found);
}
EXPORT_SYMBOL(w1_add_master_device);
EXPORT_SYMBOL(w1_remove_master_device);