i2c: Add i2c_new_dummy() utility
This adds a i2c_new_dummy() primitive to help work with devices
that consume multiple addresses, which include many I2C eeproms
and at least one RTC.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index cd3fcb8..96da22e 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -296,6 +296,50 @@
EXPORT_SYMBOL_GPL(i2c_unregister_device);
+static int dummy_nop(struct i2c_client *client)
+{
+ return 0;
+}
+
+static struct i2c_driver dummy_driver = {
+ .driver.name = "dummy",
+ .probe = dummy_nop,
+ .remove = dummy_nop,
+};
+
+/**
+ * i2c_new_dummy - return a new i2c device bound to a dummy driver
+ * @adapter: the adapter managing the device
+ * @address: seven bit address to be used
+ * @type: optional label used for i2c_client.name
+ * Context: can sleep
+ *
+ * This returns an I2C client bound to the "dummy" driver, intended for use
+ * with devices that consume multiple addresses. Examples of such chips
+ * include various EEPROMS (like 24c04 and 24c08 models).
+ *
+ * These dummy devices have two main uses. First, most I2C and SMBus calls
+ * except i2c_transfer() need a client handle; the dummy will be that handle.
+ * And second, this prevents the specified address from being bound to a
+ * different driver.
+ *
+ * This returns the new i2c client, which should be saved for later use with
+ * i2c_unregister_device(); or NULL to indicate an error.
+ */
+struct i2c_client *
+i2c_new_dummy(struct i2c_adapter *adapter, u16 address, const char *type)
+{
+ struct i2c_board_info info = {
+ .driver_name = "dummy",
+ .addr = address,
+ };
+
+ if (type)
+ strlcpy(info.type, type, sizeof info.type);
+ return i2c_new_device(adapter, &info);
+}
+EXPORT_SYMBOL_GPL(i2c_new_dummy);
+
/* ------------------------------------------------------------------------- */
/* I2C bus adapters -- one roots each I2C or SMBUS segment */
@@ -841,11 +885,24 @@
retval = bus_register(&i2c_bus_type);
if (retval)
return retval;
- return class_register(&i2c_adapter_class);
+ retval = class_register(&i2c_adapter_class);
+ if (retval)
+ goto bus_err;
+ retval = i2c_add_driver(&dummy_driver);
+ if (retval)
+ goto class_err;
+ return 0;
+
+class_err:
+ class_unregister(&i2c_adapter_class);
+bus_err:
+ bus_unregister(&i2c_bus_type);
+ return retval;
}
static void __exit i2c_exit(void)
{
+ i2c_del_driver(&dummy_driver);
class_unregister(&i2c_adapter_class);
bus_unregister(&i2c_bus_type);
}