i2c: Use the driver model reference counting

Don't implement our own reference counting mechanism for i2c clients
when the driver model already has one.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: David Brownell <david-b@pacbell.net>

3 files changed, 2 insertions, 48 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 7788e1730063..9b9d808578b9 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -696,8 +696,6 @@ int i2c_attach_client(struct i2c_client *client)
         }
         list_add_tail(&client->list,&adapter->clients);
 
-        client->usage_count = 0;
-
         client->dev.parent = &client->adapter->dev;
         client->dev.bus = &i2c_bus_type;
 
@@ -744,12 +742,6 @@ int i2c_detach_client(struct i2c_client *client)
         struct i2c_adapter *adapter = client->adapter;
         int res = 0;
 
-        if (client->usage_count > 0) {
-                dev_warn(&client->dev, "Client [%s] still busy, "
-                         "can't detach\n", client->name);
-                return -EBUSY;
-        }
-
         if (adapter->client_unregister)  {
                 res = adapter->client_unregister(client);
                 if (res) {
@@ -772,50 +764,16 @@ int i2c_detach_client(struct i2c_client *client)
 }
 EXPORT_SYMBOL(i2c_detach_client);
 
-static int i2c_inc_use_client(struct i2c_client *client)
-{
-
-        if (!try_module_get(client->driver->driver.owner))
-                return -ENODEV;
-        if (!try_module_get(client->adapter->owner)) {
-                module_put(client->driver->driver.owner);
-                return -ENODEV;
-        }
-
-        return 0;
-}
-
-static void i2c_dec_use_client(struct i2c_client *client)
-{
-        module_put(client->driver->driver.owner);
-        module_put(client->adapter->owner);
-}
-
 int i2c_use_client(struct i2c_client *client)
 {
-        int ret;
-
-        ret = i2c_inc_use_client(client);
-        if (ret)
-                return ret;
-
-        client->usage_count++;
-
+        get_device(&client->dev);
         return 0;
 }
 EXPORT_SYMBOL(i2c_use_client);
 
 int i2c_release_client(struct i2c_client *client)
 {
-        if (!client->usage_count) {
-                pr_debug("i2c-core: %s used one too many times\n",
-                         __FUNCTION__);
-                return -EPERM;
-        }
-
-        client->usage_count--;
-        i2c_dec_use_client(client);
-
+        put_device(&client->dev);
         return 0;
 }
 EXPORT_SYMBOL(i2c_release_client);
diff --git a/drivers/media/video/ks0127.c b/drivers/media/video/ks0127.c
index b6cd21e6dab9..4895540be195 100644
--- a/drivers/media/video/ks0127.c
+++ b/drivers/media/video/ks0127.c
@@ -764,7 +764,6 @@ static struct i2c_client ks0127_client_tmpl =
         .addr = 0,
         .adapter = NULL,
         .driver = &i2c_driver_ks0127,
-        .usage_count = 0
 };
 
 static int ks0127_found_proc(struct i2c_adapter *adapter, int addr, int kind)
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 37c14b08d61a..f7cd2f370c39 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -155,7 +155,6 @@ struct i2c_driver {
  *      generic enough to hide second-sourcing and compatible revisions.
  * @adapter: manages the bus segment hosting this I2C device
  * @driver: device's driver, hence pointer to access routines
- * @usage_count: counts current number of users of this client
  * @dev: Driver model device node for the slave.
  * @irq: indicates the IRQ generated by this device (if any)
  * @driver_name: Identifies new-style driver used with this device; also
@@ -175,8 +174,6 @@ struct i2c_client {
         char name[I2C_NAME_SIZE];
         struct i2c_adapter *adapter;    /* the adapter we sit on        */
         struct i2c_driver *driver;      /* and our access routines      */
-        int usage_count;                /* How many accesses currently  */
-                                        /* to the client                */
         struct device dev;              /* the device structure         */
         int irq;                        /* irq issued by device (or -1) */
         char driver_name[KOBJ_NAME_LEN];