[PATCH v3 3/7] i2c: implement rescan

[Sascha Hauer]

struct device::rescan is called by the core to let the subsystem rescan
the controllers device node. Implement that for I2C. Ahmad recently
implemented the struct device::detect hook for the very same purpose.
The downside of that approach was that device_detect() had to be called
manually and that either needs knowledge which device actually has
updated device nodes, or all devices were detected, like unrelated USB
or MMC/SD devices. The rescan hook doesn't need that manual detect call,
so just drop the I2C detect implementation in favour for implementing
rescan.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 drivers/i2c/i2c.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/drivers/i2c/i2c.c b/drivers/i2c/i2c.c
index efcad29342..4c7b7008ce 100644
--- a/drivers/i2c/i2c.c
+++ b/drivers/i2c/i2c.c
@@ -420,6 +420,10 @@ static void of_i2c_register_devices(struct i2c_adapter *adap)
 {
 	struct device_node *n;
 
+	/* Only register child devices if the adapter has a node pointer set */
+	if (!IS_ENABLED(CONFIG_OFDEVICE) || !adap->dev.of_node)
+		return;
+
 	for_each_available_child_of_node(adap->dev.of_node, n) {
 		struct i2c_board_info info = {};
 		struct i2c_client *result;
@@ -471,15 +475,7 @@ int of_i2c_register_devices_by_node(struct device_node *node)
 	return 0;
 }
 
-static int i2c_bus_detect(struct device *dev)
-{
-	struct i2c_adapter *adap = container_of(dev, struct i2c_adapter, dev);
-
-	of_i2c_register_devices(adap);
-	return 0;
-}
-
-static int i2c_hw_detect(struct device *dev)
+static void i2c_hw_rescan(struct device *dev)
 {
 	struct i2c_adapter *adap;
 
@@ -489,8 +485,6 @@ static int i2c_hw_detect(struct device *dev)
 		of_i2c_register_devices(adap);
 		break;
 	}
-
-	return 0;
 }
 
 /**
@@ -720,7 +714,6 @@ int i2c_add_numbered_adapter(struct i2c_adapter *adapter)
 	}
 
 	adapter->dev.id = adapter->nr;
-	adapter->dev.detect = i2c_bus_detect;
 	dev_set_name(&adapter->dev, "i2c");
 
 	ret = register_device(&adapter->dev);
@@ -732,11 +725,12 @@ int i2c_add_numbered_adapter(struct i2c_adapter *adapter)
 	/* populate children from any i2c device tables */
 	scan_boardinfo(adapter);
 
+	of_i2c_register_devices(adapter);
+
 	hw_dev = adapter->dev.parent;
 	if (hw_dev && dev_of_node(hw_dev)) {
-		if (!hw_dev->detect)
-			hw_dev->detect = i2c_hw_detect;
-		i2c_hw_detect(hw_dev);
+		if (!hw_dev->rescan)
+			hw_dev->rescan = i2c_hw_rescan;
 	}
 
 	return 0;
-- 
2.30.2