[34-longterm 055/247] i2c: Unregister dummy devices last on adapter removal

From: Paul Gortmaker
Date: Thu Jun 23 2011 - 13:30:04 EST

From: Jean Delvare <khali@xxxxxxxxxxxx>

This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.

commit 5219bf884b6e2b54e734ca1799b6f0014bb2b4b7 upstream.

Remove real devices first and dummy devices last. This gives device
driver which instantiated dummy devices themselves a chance to clean
them up before we do.

Signed-off-by: Jean Delvare <khali@xxxxxxxxxxxx>
Tested-by: Hans Verkuil <hverkuil@xxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
drivers/i2c/i2c-core.c | 14 +++++++++++++-
1 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index c2258a5..b67109c 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -837,6 +837,14 @@ static int i2c_do_del_adapter(struct i2c_driver *driver,
static int __unregister_client(struct device *dev, void *dummy)
struct i2c_client *client = i2c_verify_client(dev);
+ if (client && strcmp(client->name, "dummy"))
+ i2c_unregister_device(client);
+ return 0;
+static int __unregister_dummy(struct device *dev, void *dummy)
+ struct i2c_client *client = i2c_verify_client(dev);
if (client)
return 0;
@@ -891,8 +899,12 @@ int i2c_del_adapter(struct i2c_adapter *adap)

/* Detach any active clients. This can't fail, thus we do not
- checking the returned value. */
+ * check the returned value. This is a two-pass process, because
+ * we can't remove the dummy devices during the first pass: they
+ * could have been instantiated by real devices wishing to clean
+ * them up properly, so we give them a chance to do that first. */
res = device_for_each_child(&adap->dev, NULL, __unregister_client);
+ res = device_for_each_child(&adap->dev, NULL, __unregister_dummy);

class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,

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