of/i2c: implement of_find_i2c_adapter_by_node

This finds the struct i2c_adapter * for a given device tree node. Just
like of_find_i2c_device_by_node.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

2 files changed, 18 insertions, 0 deletions

diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
index 068488717f69..1e173f357674 100644
--- a/drivers/of/of_i2c.c
+++ b/drivers/of/of_i2c.c
@@ -94,4 +94,18 @@ struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 }
 EXPORT_SYMBOL(of_find_i2c_device_by_node);
 
+/* must call put_device() when done with returned i2c_adapter device */
+struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
+{
+        struct device *dev;
+
+        dev = bus_find_device(&i2c_bus_type, NULL, node,
+                                         of_dev_node_match);
+        if (!dev)
+                return NULL;
+
+        return i2c_verify_adapter(dev);
+}
+EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
+
 MODULE_LICENSE("GPL");
diff --git a/include/linux/of_i2c.h b/include/linux/of_i2c.h
index 0efe8d465f55..1cb775f8e663 100644
--- a/include/linux/of_i2c.h
+++ b/include/linux/of_i2c.h
@@ -20,6 +20,10 @@ extern void of_i2c_register_devices(struct i2c_adapter *adap);
 /* must call put_device() when done with returned i2c_client device */
 extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
 
+/* must call put_device() when done with returned i2c_adapter device */
+extern struct i2c_adapter *of_find_i2c_adapter_by_node(
+                                                struct device_node *node);
+
 #else
 static inline void of_i2c_register_devices(struct i2c_adapter *adap)
 {