Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa...

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

diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
index f31b2ad..5fa691e 100644 (file)
--- 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
        specification.

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 45c8817..e422568 100644 (file)
--- 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));
 

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 98fffa3..5ab6721 100644 (file)
--- 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))
                        continue;
                of_i2c_register_device(adap, node);
        }
+
+       of_node_put(bus);
 }
 
 static int of_dev_node_match(struct device *dev, void *data)