diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-14 13:09:41 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-14 13:09:41 -0700 |
| commit | e5050143d67c80a8705d6fcf5f9972663a0f082e (patch) | |
| tree | 4d5259c31bc07a1a99f6d6ed8dba4ef88485dd13 /drivers/gpio/gpio-pca953x.c | |
| parent | b41d037a1fd32d6535a2eef877b10f8deefeaf70 (diff) | |
| parent | b2edcdae3d9a29b25f6c161a8711caa74ce49991 (diff) | |
Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull more i2c updates from Wolfram Sang:
"A small update pull request from I2C.
This adds one comment to a change we did in this merge window to
handle lockdep better, and pulls in a branch which should have been in
4.8 already improving DT support for I2C"
* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
gpio: pca953x: add a comment explaining the need for a lockdep subclass
i2c: core: Add support for 'i2c-bus' subnode
dt-bindings: i2c: Add support for 'i2c-bus' subnode
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)); |