[PATCH] w1: Adds a sysfs entry (w1_master_search) that allows you to disable/enable periodic searches.

Adds a sysfs entry (w1_master_search) that allows you to disable/enable
periodic searches.

Signed-off-by: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 51 insertions, 1 deletions

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 4fa959f08554..48da17596d43 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -148,6 +148,39 @@ static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_a
         return count;
 }
 
+static ssize_t w1_master_attribute_store_search(struct device * dev,
+                                                struct device_attribute *attr,
+                                                const char * buf, size_t count)
+{
+        struct w1_master *md = container_of(dev, struct w1_master, dev);
+
+        if (down_interruptible (&md->mutex))
+                return -EBUSY;
+
+        md->search_count = simple_strtol(buf, NULL, 0);
+
+        up(&md->mutex);
+
+        return count;
+}
+
+static ssize_t w1_master_attribute_show_search(struct device *dev,
+                                               struct device_attribute *attr,
+                                               char *buf)
+{
+        struct w1_master *md = container_of(dev, struct w1_master, dev);
+        ssize_t count;
+
+        if (down_interruptible (&md->mutex))
+                return -EBUSY;
+
+        count = sprintf(buf, "%d\n", md->search_count);
+
+        up(&md->mutex);
+
+        return count;
+}
+
 static ssize_t w1_master_attribute_show_pointer(struct device *dev, struct device_attribute *attr, char *buf)
 {
         struct w1_master *md = container_of(dev, struct w1_master, dev);
@@ -242,6 +275,12 @@ static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device
                 __ATTR(w1_master_##_name, _mode,                \
                        w1_master_attribute_show_##_name, NULL)
 
+#define W1_MASTER_ATTR_RW(_name, _mode)                         \
+        struct device_attribute w1_master_attribute_##_name =   \
+                __ATTR(w1_master_##_name, _mode,                \
+                       w1_master_attribute_show_##_name,        \
+                       w1_master_attribute_store_##_name)
+
 static W1_MASTER_ATTR_RO(name, S_IRUGO);
 static W1_MASTER_ATTR_RO(slaves, S_IRUGO);
 static W1_MASTER_ATTR_RO(slave_count, S_IRUGO);
@@ -249,6 +288,7 @@ static W1_MASTER_ATTR_RO(max_slave_count, S_IRUGO);
 static W1_MASTER_ATTR_RO(attempts, S_IRUGO);
 static W1_MASTER_ATTR_RO(timeout, S_IRUGO);
 static W1_MASTER_ATTR_RO(pointer, S_IRUGO);
+static W1_MASTER_ATTR_RW(search, S_IRUGO | S_IWUGO);
 
 static struct attribute *w1_master_default_attrs[] = {
         &w1_master_attribute_name.attr,
@@ -258,6 +298,7 @@ static struct attribute *w1_master_default_attrs[] = {
         &w1_master_attribute_attempts.attr,
         &w1_master_attribute_timeout.attr,
         &w1_master_attribute_pointer.attr,
+        &w1_master_attribute_search.attr,
         NULL
 };
 
@@ -643,11 +684,14 @@ int w1_process(void *data)
                 if (!dev->initialized)
                         continue;
 
+                if (dev->search_count == 0)
+                        continue;
+
                 if (down_interruptible(&dev->mutex))
                         continue;
 
                 list_for_each_entry(sl, &dev->slist, w1_slave_entry)
-                                clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
+                        clear_bit(W1_SLAVE_ACTIVE, (long *)&sl->flags);
 
                 w1_search_devices(dev, w1_slave_found);
 
@@ -662,6 +706,10 @@ int w1_process(void *data)
                         } else if (test_bit(W1_SLAVE_ACTIVE, (unsigned long *)&sl->flags))
                                 sl->ttl = dev->slave_ttl;
                 }
+
+                if (dev->search_count > 0)
+                        dev->search_count--;
+
                 up(&dev->mutex);
         }
 
diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
index 3cfdd08d32fc..6b5f7be50b8a 100644
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -162,6 +162,7 @@ struct w1_master
         int                     slave_ttl;
         int                     initialized;
         u32                     id;
+        int                     search_count;
 
         atomic_t                refcnt;
 
diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index 280f140ae698..cf18f1324f03 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -69,6 +69,7 @@ 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 */
 
         atomic_set(&dev->refcnt, 2);