i2c: implement i2c_get_adapter()

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Eric Bénard <eric@eukrea.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

2 files changed, 25 insertions, 1 deletions

diff --git a/drivers/i2c/i2c.c b/drivers/i2c/i2c.c
index 32fd026de5..1fa114a31c 100644
--- a/drivers/i2c/i2c.c
+++ b/drivers/i2c/i2c.c
@@ -39,7 +39,7 @@ struct boardinfo {
 };
 
 static LIST_HEAD(board_list);
-
+static LIST_HEAD(adapter_list);
 
 /**
  * i2c_transfer - execute a single or combined I2C message
@@ -327,6 +327,23 @@ static void scan_boardinfo(struct i2c_adapter *adapter)
 }
 
 /**
+ *
+ * i2c_get_adapter - get an i2c adapter from its busnum
+ *
+ * @param	busnum	the desired bus number
+ *
+ */
+struct i2c_adapter *i2c_get_adapter(int busnum)
+{
+	struct i2c_adapter *adap;
+
+	list_for_each_entry(adap, &adapter_list, list)
+		if (adap->nr == busnum)
+			return adap;
+	return NULL;
+}
+
+/**
  * i2c_register_master - register I2C master controller
  *
  * @param	master	initialized master, originally from i2c_alloc_master()
@@ -345,6 +362,11 @@ static void scan_boardinfo(struct i2c_adapter *adapter)
  */
 int i2c_add_numbered_adapter(struct i2c_adapter *adapter)
 {
+	if (i2c_get_adapter(adapter->nr))
+		return -EBUSY;
+
+	list_add_tail(&adapter_list, &adapter->list);
+
 	/* populate children from any i2c device tables */
 	scan_boardinfo(adapter);
 
diff --git a/include/i2c/i2c.h b/include/i2c/i2c.h
index 0760fdc10c..c031bbbb62 100644
--- a/include/i2c/i2c.h
+++ b/include/i2c/i2c.h
@@ -66,6 +66,7 @@ struct i2c_adapter {
 	struct device_d		*dev;	/* ptr to device */
 	int			nr;	/* bus number */
 	int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
+	struct list_head	list;
 };
 
 
@@ -120,6 +121,7 @@ static inline int i2c_register_board_info(int busnum,
 }
 #endif
 extern int i2c_add_numbered_adapter(struct i2c_adapter *adapter);
+struct i2c_adapter *i2c_get_adapter(int busnum);
 
 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
 extern int i2c_master_send(struct i2c_client *client, const char *buf, int count);