diff options
authorLinus Torvalds <>2016-10-14 13:09:41 -0700
committerLinus Torvalds <>2016-10-14 13:09:41 -0700
commite5050143d67c80a8705d6fcf5f9972663a0f082e (patch)
parentb41d037a1fd32d6535a2eef877b10f8deefeaf70 (diff)
parentb2edcdae3d9a29b25f6c161a8711caa74ce49991 (diff)
Merge branch 'i2c/for-next' of git://
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:// 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
3 files changed, 32 insertions, 2 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
index f31b2ad1552b..5fa691e6f638 100644
--- a/Documentation/devicetree/bindings/i2c/i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c.txt
@@ -32,6 +32,14 @@ wants to support one of the below features, it should adapt the bindings below.
- clock-frequency
frequency of bus clock in Hz.
+- i2c-bus
+ For I2C adapters that have child nodes that are a mixture of both I2C
+ devices and non-I2C devices, the 'i2c-bus' subnode can be used for
+ populating I2C devices. If the 'i2c-bus' subnode is present, only
+ subnodes of this will be considered as I2C slaves. The properties,
+ '#address-cells' and '#size-cells' must be defined under this subnode
+ if present.
- i2c-scl-falling-time-ns
Number of nanoseconds the SCL signal takes to fall; t(f) in the I2C
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,
+ /*
+ * 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).
+ */
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 98fffa3a09f7..5ab67219f71e 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1680,7 +1680,7 @@ static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
static void of_i2c_register_devices(struct i2c_adapter *adap)
- struct device_node *node;
+ struct device_node *bus, *node;
/* Only register child devices if the adapter has a node pointer set */
if (!adap->dev.of_node)
@@ -1688,11 +1688,17 @@ 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) {
+ bus = of_get_child_by_name(adap->dev.of_node, "i2c-bus");
+ if (!bus)
+ bus = of_node_get(adap->dev.of_node);
+ for_each_available_child_of_node(bus, node) {
if (of_node_test_and_set_flag(node, OF_POPULATED))
of_i2c_register_device(adap, node);
+ of_node_put(bus);
static int of_dev_node_match(struct device *dev, void *data)