i2c: Add support for custom probe function

The probe method used by i2c_new_probed_device() may not be suitable
for all cases. Let the caller provide its own, optional probe
function.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 38dd402..59a9f3c 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -284,12 +284,15 @@
 
 /* If you don't know the exact address of an I2C device, use this variant
  * instead, which can probe for device presence in a list of possible
- * addresses.
+ * addresses. The "probe" callback function is optional. If it is provided,
+ * it must return 1 on successful probe, 0 otherwise. If it is not provided,
+ * a default probing method is used.
  */
 extern struct i2c_client *
 i2c_new_probed_device(struct i2c_adapter *adap,
 		      struct i2c_board_info *info,
-		      unsigned short const *addr_list);
+		      unsigned short const *addr_list,
+		      int (*probe)(struct i2c_adapter *, unsigned short addr));
 
 /* For devices that use several addresses, use i2c_new_dummy() to make
  * client handles for the extra addresses.