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path: root/drivers/w1/w1_int.c
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Diffstat (limited to 'drivers/w1/w1_int.c')
-rw-r--r--drivers/w1/w1_int.c88
1 files changed, 72 insertions, 16 deletions
diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index 6840dfebe4d4..a3a54567bfba 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -29,7 +29,11 @@
#include "w1_netlink.h"
#include "w1_int.h"
-static u32 w1_ids = 1;
+static int w1_search_count = -1; /* Default is continual scan */
+module_param_named(search_count, w1_search_count, int, 0);
+
+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,
@@ -59,8 +63,12 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
dev->initialized = 0;
dev->id = id;
dev->slave_ttl = slave_ttl;
- dev->search_count = -1; /* continual scan */
+ dev->search_count = w1_search_count;
+ 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);
@@ -93,9 +101,10 @@ static void w1_free_dev(struct w1_master *dev)
int w1_add_master_device(struct w1_bus_master *master)
{
- struct w1_master *dev;
+ 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) &&
@@ -104,10 +113,50 @@ int w1_add_master_device(struct w1_bus_master *master)
printk(KERN_ERR "w1_add_master_device: invalid function set\n");
return(-EINVAL);
}
+ /* 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(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
- if (!dev)
+ 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)) {
@@ -115,18 +164,10 @@ int w1_add_master_device(struct w1_bus_master *master)
dev_err(&dev->dev,
"Failed to create new kernel thread. err=%d\n",
retval);
- goto err_out_free_dev;
+ mutex_unlock(&w1_mlock);
+ goto err_out_rm_attr;
}
- retval = w1_create_master_attributes(dev);
- if (retval)
- goto err_out_kill_thread;
-
- memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
-
- dev->initialized = 1;
-
- mutex_lock(&w1_mlock);
list_add(&dev->w1_master_entry, &w1_masters);
mutex_unlock(&w1_mlock);
@@ -137,8 +178,12 @@ int w1_add_master_device(struct w1_bus_master *master)
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);
@@ -148,10 +193,21 @@ err_out_free_dev:
void __w1_remove_master_device(struct w1_master *dev)
{
struct w1_netlink_msg msg;
+ struct w1_slave *sl, *sln;
- set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
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));