i2c: i2c stack can remove()

More update for new style driver support:  add a remove() method, and
use it in the relevant code paths.

Again, nothing will use this yet since there's nothing to create devices
feeding this infrastructure.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

2 files changed, 62 insertions, 4 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index a2ad83ad0f53..3aac1b5c7cbd 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -41,6 +41,7 @@ static LIST_HEAD(drivers);
 static DEFINE_MUTEX(core_lists);
 static DEFINE_IDR(i2c_adapter_idr);
 
+#define is_newstyle_driver(d) ((d)->probe || (d)->remove)
 
 /* ------------------------------------------------------------------------- */
 
@@ -52,7 +53,7 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
         /* make legacy i2c drivers bypass driver model probing entirely;
          * such drivers scan each i2c adapter/bus themselves.
          */
-        if (!driver->probe)
+        if (!is_newstyle_driver(driver))
                 return 0;
 
         /* new style drivers use the same kind of driver matching policy
@@ -100,7 +101,24 @@ static int i2c_device_probe(struct device *dev)
 
 static int i2c_device_remove(struct device *dev)
 {
-        return 0;
+        struct i2c_client       *client = to_i2c_client(dev);
+        struct i2c_driver       *driver;
+        int                     status;
+
+        if (!dev->driver)
+                return 0;
+
+        driver = to_i2c_driver(dev->driver);
+        if (driver->remove) {
+                dev_dbg(dev, "remove\n");
+                status = driver->remove(client);
+        } else {
+                dev->driver = NULL;
+                status = 0;
+        }
+        if (status == 0)
+                client->driver = NULL;
+        return status;
 }
 
 static void i2c_device_shutdown(struct device *dev)
@@ -177,6 +195,26 @@ struct bus_type i2c_bus_type = {
         .resume         = i2c_device_resume,
 };
 
+static void i2c_unregister_device(struct i2c_client *client)
+{
+        struct i2c_adapter      *adapter = client->adapter;
+        struct i2c_driver       *driver = client->driver;
+
+        if (driver && !is_newstyle_driver(driver)) {
+                dev_err(&client->dev, "can't unregister devices "
+                        "with legacy drivers\n");
+                WARN_ON(1);
+                return;
+        }
+
+        mutex_lock(&adapter->clist_lock);
+        list_del(&client->list);
+        mutex_unlock(&adapter->clist_lock);
+
+        device_unregister(&client->dev);
+}
+
+
 /* ------------------------------------------------------------------------- */
 
 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
@@ -310,9 +348,19 @@ int i2c_del_adapter(struct i2c_adapter *adap)
         /* detach any active clients. This must be done first, because
          * it can fail; in which case we give up. */
         list_for_each_safe(item, _n, &adap->clients) {
+                struct i2c_driver       *driver;
+
                 client = list_entry(item, struct i2c_client, list);
+                driver = client->driver;
 
-                if ((res=client->driver->detach_client(client))) {
+                /* new style, follow standard driver model */
+                if (!driver || is_newstyle_driver(driver)) {
+                        i2c_unregister_device(client);
+                        continue;
+                }
+
+                /* legacy drivers create and remove clients themselves */
+                if ((res = driver->detach_client(client))) {
                         dev_err(&adap->dev, "detach_client failed for client "
                                 "[%s] at address 0x%02x\n", client->name,
                                 client->addr);
@@ -355,7 +403,7 @@ int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
         int res;
 
         /* new style driver methods can't mix with legacy ones */
-        if (driver->probe) {
+        if (is_newstyle_driver(driver)) {
                 if (driver->attach_adapter || driver->detach_adapter
                                 || driver->detach_client) {
                         printk(KERN_WARNING
@@ -392,6 +440,10 @@ int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
 }
 EXPORT_SYMBOL(i2c_register_driver);
 
+/**
+ * i2c_del_driver - unregister I2C driver
+ * @driver: the driver being unregistered
+ */
 int i2c_del_driver(struct i2c_driver *driver)
 {
         struct list_head   *item1, *item2, *_n;
@@ -402,6 +454,10 @@ int i2c_del_driver(struct i2c_driver *driver)
 
         mutex_lock(&core_lists);
 
+        /* new-style driver? */
+        if (is_newstyle_driver(driver))
+                goto unregister;
+
         /* Have a look at each adapter, if clients of this driver are still
          * attached. If so, detach them to be able to kill the driver
          * afterwards.
@@ -434,6 +490,7 @@ int i2c_del_driver(struct i2c_driver *driver)
                 }
         }
 
+ unregister:
         driver_unregister(&driver->driver);
         list_del(&driver->list);
         pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 8dcccc0f4822..6802c3a0a3a3 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -130,6 +130,7 @@ struct i2c_driver {
          * it's done by infrastructure.  (NEW STYLE DRIVERS ONLY)
          */
         int (*probe)(struct i2c_client *);
+        int (*remove)(struct i2c_client *);
 
         /* driver model interfaces that don't relate to enumeration  */
         void (*shutdown)(struct i2c_client *);