3 files changed, 84 insertions, 5 deletions

diff --git a/Documentation/w1/w1.generic b/Documentation/w1/w1.generic
index f937fbe1cacb..4c6509dd4789 100644
--- a/Documentation/w1/w1.generic
+++ b/Documentation/w1/w1.generic
@@ -27,8 +27,19 @@ When a w1 master driver registers with the w1 subsystem, the following occurs:
 
 When a device is found on the bus, w1 core checks if driver for it's family is
 loaded. If so, the family driver is attached to the slave.
-If there is no driver for the family, a simple sysfs entry is created
-for the slave device.
+If there is no driver for the family, default one is assigned, which allows to perform
+almost any kind of operations. Each logical operation is a transaction
+in nature, which can contain several (two or one) low-level operations.
+Let's see how one can read EEPROM context:
+1. one must write control buffer, i.e. buffer containing command byte
+and two byte address. At this step bus is reset and appropriate device
+is selected using either W1_SKIP_ROM or W1_MATCH_ROM command.
+Then provided control buffer is being written to the wire.
+2. reading. This will issue reading eeprom response.
+
+It is possible that between 1. and 2. w1 master thread will reset bus for searching
+and slave device will be even removed, but in this case 0xff will
+be read, since no device was selected.
 
 
 W1 device families
@@ -89,4 +100,5 @@ driver             - (standard) symlink to the w1 driver
 name               - the device name, usually the same as the directory name
 w1_slave           - (optional) a binary file whose meaning depends on the
                      family driver
-
+rw                 - (optional) created for slave devices which do not have
+                     appropriate family driver. Allows to read/write binary data.
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index a698b517e863..c9486c168505 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -139,7 +139,74 @@ static struct bin_attribute w1_slave_attr_bin_id = {
 };
 
 /* Default family */
-static struct w1_family w1_default_family;
+
+static ssize_t w1_default_write(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+        struct w1_slave *sl = kobj_to_w1_slave(kobj);
+
+        if (down_interruptible(&sl->master->mutex)) {
+                count = 0;
+                goto out;
+        }
+
+        if (w1_reset_select_slave(sl)) {
+                count = 0;
+                goto out_up;
+        }
+
+        w1_write_block(sl->master, buf, count);
+
+out_up:
+        up(&sl->master->mutex);
+out:
+        return count;
+}
+
+static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+        struct w1_slave *sl = kobj_to_w1_slave(kobj);
+
+        if (down_interruptible(&sl->master->mutex)) {
+                count = 0;
+                goto out;
+        }
+
+        w1_read_block(sl->master, buf, count);
+
+        up(&sl->master->mutex);
+out:
+        return count;
+}
+
+static struct bin_attribute w1_default_attr = {
+      .attr = {
+              .name = "rw",
+              .mode = S_IRUGO | S_IWUSR,
+              .owner = THIS_MODULE,
+      },
+      .size = PAGE_SIZE,
+      .read = w1_default_read,
+      .write = w1_default_write,
+};
+
+static int w1_default_add_slave(struct w1_slave *sl)
+{
+        return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr);
+}
+
+static void w1_default_remove_slave(struct w1_slave *sl)
+{
+        sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr);
+}
+
+static struct w1_family_ops w1_default_fops = {
+        .add_slave      = w1_default_add_slave,
+        .remove_slave   = w1_default_remove_slave,
+};
+
+static struct w1_family w1_default_family = {
+        .fops = &w1_default_fops,
+};
 
 static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size);
 
diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
index 56980505e6c4..02e8caddfb36 100644
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -60,7 +60,7 @@ struct w1_reg_num
 #define W1_READ_PSUPPLY         0xB4
 #define W1_MATCH_ROM            0x55
 
-#define W1_SLAVE_ACTIVE         (1<<0)
+#define W1_SLAVE_ACTIVE         0
 
 struct w1_slave
 {