[PATCH 2/9] i2c: Add the ability to match device to compatible string without an of_node

[Lee Jones <lee.jones@linaro.org>]

A great deal of I2C devices are currently matched via DT node name, and
as such the compatible naming convention of '<vendor>,<device>' has gone
somewhat awry - some nodes don't supply one, some supply an arbitrary
string and others the correct device name with an arbitrary vendor prefix.

In an effort to correct this problem we have to supply a mechanism to
match a device by compatible string AND by simple device name.  This
function strips off the '<vendor>,' part of a supplied compatible string
and attempts to match without it.

The plan is to remove this function once all of the compatible strings
for each device have been brought into line.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/i2c/i2c-core.c | 25 +++++++++++++++++++++++++
 include/linux/i2c.h    | 10 ++++++++++
 2 files changed, 35 insertions(+)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index d3802dc..face8f9 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1090,6 +1090,31 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 	return i2c_verify_adapter(dev);
 }
 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
+
+const struct of_device_id
+*i2c_of_match_device_strip_vendor(const struct of_device_id *matches,
+				  struct device *dev)
+{
+	const struct i2c_client *client = i2c_verify_client(dev);
+	const char *name;
+
+	if (!(client && matches))
+		return NULL;
+
+	for (; matches->compatible[0]; matches++) {
+		name = strchr(matches->compatible, ',');
+		if (!name)
+			name = matches->compatible;
+		else
+			name++;
+
+		if (!strnicmp(client->name, name, strlen(client->name)))
+			return matches;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(i2c_of_match_device_strip_vendor);
 #else
 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
 #endif /* CONFIG_OF */
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index b556e0a..f7ec75b 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -564,6 +564,9 @@ 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);
 
+extern const struct of_device_id
+*i2c_of_match_device_strip_vendor(const struct of_device_id *matches,
+				  struct device *dev);
 #else
 
 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
@@ -575,6 +578,13 @@ static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node
 {
 	return NULL;
 }
+
+const struct of_device_id
+*i2c_of_match_device_strip_vendor(const struct of_device_id *matches,
+				  struct device *dev)
+{
+	return NULL;
+}
 #endif /* CONFIG_OF */
 
 #endif /* _LINUX_I2C_H */
-- 
1.8.3.2