i2c: Mark instantiated device nodes with OF_POPULATE

Mark (and unmark) device nodes with the POPULATE flag as appropriate.
This is required to avoid multi probing when using I2C and device
overlays containing a mux.
This patch is also more careful with the release of the adapter device
which caused a deadlock with muxes, and does not break the build
on !OF since the node flag accessors are not defined then.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 069a41f116dd..e6d4935161e4 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1012,6 +1012,8 @@ EXPORT_SYMBOL_GPL(i2c_new_device);
  */
 void i2c_unregister_device(struct i2c_client *client)
 {
+        if (client->dev.of_node)
+                of_node_clear_flag(client->dev.of_node, OF_POPULATED);
         device_unregister(&client->dev);
 }
 EXPORT_SYMBOL_GPL(i2c_unregister_device);
@@ -1320,8 +1322,11 @@ static void of_i2c_register_devices(struct i2c_adapter *adap)
 
         dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
 
-        for_each_available_child_of_node(adap->dev.of_node, node)
+        for_each_available_child_of_node(adap->dev.of_node, node) {
+                if (of_node_test_and_set_flag(node, OF_POPULATED))
+                        continue;
                 of_i2c_register_device(adap, node);
+        }
 }
 
 static int of_dev_node_match(struct device *dev, void *data)
@@ -1853,6 +1858,11 @@ static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
                 if (adap == NULL)
                         return NOTIFY_OK;       /* not for us */
 
+                if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
+                        put_device(&adap->dev);
+                        return NOTIFY_OK;
+                }
+
                 client = of_i2c_register_device(adap, rd->dn);
                 put_device(&adap->dev);
 
@@ -1863,6 +1873,10 @@ static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
                 }
                 break;
         case OF_RECONFIG_CHANGE_REMOVE:
+                /* already depopulated? */
+                if (!of_node_check_flag(rd->dn, OF_POPULATED))
+                        return NOTIFY_OK;
+
                 /* find our device by node */
                 client = of_find_i2c_device_by_node(rd->dn);
                 if (client == NULL)