This function resolves an OF device node to an I2C adapter registered
with the I2C core.
Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx>
---
drivers/i2c/i2c-core.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/of_i2c.h | 7 +++++++
2 files changed, 41 insertions(+)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index feb7dc3..e73b044 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1627,6 +1627,40 @@ void i2c_put_adapter(struct i2c_adapter *adap)
}
EXPORT_SYMBOL(i2c_put_adapter);
+#ifdef CONFIG_OF
+static int of_i2c_match_node(int id, void *p, void *data)
+{
+ struct device_node *node = data;
+ struct i2c_adapter *adapter = p;
+
+ if (adapter->dev.of_node == node)
+ return id;
+
+ return 0;
+}
+
+struct i2c_adapter *of_i2c_get_adapter(struct device_node *node)
+{
+ struct i2c_adapter *adapter = NULL;
+ int err;
+
+ mutex_lock(&core_lock);
+
+ err = idr_for_each(&i2c_adapter_idr, of_i2c_match_node, node);
+ if (err < 0)
+ goto out;
+
+ adapter = idr_find(&i2c_adapter_idr, err);
+ if (adapter && !try_module_get(adapter->owner))
+ adapter = NULL;
+
+out:
+ mutex_unlock(&core_lock);
+ return adapter;
+}
+EXPORT_SYMBOL(of_i2c_get_adapter);
+#endif
+
/* The SMBus parts */
#define POLY (0x1070U << 3)
diff --git a/include/linux/of_i2c.h b/include/linux/of_i2c.h
index 0efe8d4..a35c497 100644
--- a/include/linux/of_i2c.h
+++ b/include/linux/of_i2c.h
@@ -20,11 +20,18 @@ 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);
+extern struct i2c_adapter *of_i2c_get_adapter(struct device_node *node);
+
#else
static inline void of_i2c_register_devices(struct i2c_adapter *adap)
{
return;
}
+
+static inline struct i2c_adapter *of_i2c_get_adapter(struct device_node *node)
+{
+ return NULL;
+}
#endif /* CONFIG_OF_I2C */
#endif /* __LINUX_OF_I2C_H */
--
1.7.10
--
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