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i2c: core: manage i2c bus device refcount in i2c_[get|put]_adapter

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In addition to module_get()/module_put() add get_device()/put_device()
calls into i2c_get_adapter()/i2c_put_adapter() exported
interfaces. This is done to lock I2C bus device, if it is in use by a
client.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Vladimir Zapolskiy 2015-07-27 17:30:49 +03:00 committed by Wolfram Sang
parent 141124e6e0
commit 611e12ea0f
1 changed files with 12 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

15
drivers/i2c/i2c-core.c
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@ -2413,9 +2413,15 @@ struct i2c_adapter *i2c_get_adapter(int nr)
mutex_lock(&core_lock);
adapter = idr_find(&i2c_adapter_idr, nr);
if (adapter && !try_module_get(adapter->owner))
if (!adapter)
goto exit;
if (try_module_get(adapter->owner))
get_device(&adapter->dev);
else
adapter = NULL;
exit:
mutex_unlock(&core_lock);
return adapter;
}
@ -2423,8 +2429,11 @@ EXPORT_SYMBOL(i2c_get_adapter);
void i2c_put_adapter(struct i2c_adapter *adap)
{
if (adap)
module_put(adap->owner);
if (!adap)
return;
put_device(&adap->dev);
module_put(adap->owner);
}
EXPORT_SYMBOL(i2c_put_adapter);