diff options
Diffstat (limited to 'drivers/gpio/gpio-pca953x.c')
| -rw-r--r-- | drivers/gpio/gpio-pca953x.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index 45c8817d068c..e422568e14ad 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -794,6 +794,22 @@ static int pca953x_probe(struct i2c_client *client, } mutex_init(&chip->i2c_lock); + /* + * In case we have an i2c-mux controlled by a GPIO provided by an + * expander using the same driver higher on the device tree, read the + * i2c adapter nesting depth and use the retrieved value as lockdep + * subclass for chip->i2c_lock. + * + * REVISIT: This solution is not complete. It protects us from lockdep + * false positives when the expander controlling the i2c-mux is on + * a different level on the device tree, but not when it's on the same + * level on a different branch (in which case the subclass number + * would be the same). + * + * TODO: Once a correct solution is developed, a similar fix should be + * applied to all other i2c-controlled GPIO expanders (and potentially + * regmap-i2c). + */ lockdep_set_subclass(&chip->i2c_lock, i2c_adapter_depth(client->adapter)); |