Merge branch 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging

* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  i2c: I2C bus multiplexer driver pca954x
  i2c: Multiplexed I2C bus core support
  i2c: Use a separate mutex for userspace client lists
  i2c: Make i2c_default_probe self-sufficient
  i2c: Drop dummy variable
  i2c: Move adapter locking helpers to i2c-core
  V4L/DVB: Use custom I2C probing function mechanism
  i2c: Add support for custom probe function
  i2c-dev: Use memdup_user
  i2c-dev: Remove unnecessary kmalloc casts

22 files changed, 805 insertions, 116 deletions

diff --git a/Documentation/i2c/instantiating-devices b/Documentation/i2c/instantiating-devices
index e89490270ab..87da405a859 100644
--- a/Documentation/i2c/instantiating-devices
+++ b/Documentation/i2c/instantiating-devices
@@ -102,7 +102,7 @@ static int __devinit usb_hcd_pnx4008_probe(struct platform_device *pdev)
         memset(&i2c_info, 0, sizeof(struct i2c_board_info));
         strlcpy(i2c_info.name, "isp1301_pnx", I2C_NAME_SIZE);
         isp1301_i2c_client = i2c_new_probed_device(i2c_adap, &i2c_info,
-                                                   normal_i2c);
+                                                   normal_i2c, NULL);
         i2c_put_adapter(i2c_adap);
         (...)
 }
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index d06083fdffb..30f06e956bf 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -47,6 +47,19 @@ config I2C_CHARDEV
           This support is also available as a module.  If so, the module 
           will be called i2c-dev.
 
+config I2C_MUX
+        tristate "I2C bus multiplexing support"
+        depends on EXPERIMENTAL
+        help
+          Say Y here if you want the I2C core to support the ability to
+          handle multiplexed I2C bus topologies, by presenting each
+          multiplexed segment as a I2C adapter.
+
+          This support is also available as a module.  If so, the module
+          will be called i2c-mux.
+
+source drivers/i2c/muxes/Kconfig
+
 config I2C_HELPER_AUTO
         bool "Autoselect pertinent helper modules"
         default y
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index a7d9b4be9bb..c00fd66388f 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -6,7 +6,8 @@ obj-$(CONFIG_I2C_BOARDINFO)	+= i2c-boardinfo.o
 obj-$(CONFIG_I2C)               += i2c-core.o
 obj-$(CONFIG_I2C_SMBUS)         += i2c-smbus.o
 obj-$(CONFIG_I2C_CHARDEV)       += i2c-dev.o
-obj-y                           += algos/ busses/
+obj-$(CONFIG_I2C_MUX)           += i2c-mux.o
+obj-y                           += algos/ busses/ muxes/
 
 ifeq ($(CONFIG_I2C_DEBUG_CORE),y)
 EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index df937df845e..6649176de94 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -20,7 +20,9 @@
 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
    All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
    SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
-   Jean Delvare <khali@linux-fr.org> */
+   Jean Delvare <khali@linux-fr.org>
+   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
+   Michael Lawnick <michael.lawnick.ext@nsn.com> */
 
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -423,11 +425,87 @@ static int __i2c_check_addr_busy(struct device *dev, void *addrp)
         return 0;
 }
 
+/* walk up mux tree */
+static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
+{
+        int result;
+
+        result = device_for_each_child(&adapter->dev, &addr,
+                                        __i2c_check_addr_busy);
+
+        if (!result && i2c_parent_is_i2c_adapter(adapter))
+                result = i2c_check_mux_parents(
+                                    to_i2c_adapter(adapter->dev.parent), addr);
+
+        return result;
+}
+
+/* recurse down mux tree */
+static int i2c_check_mux_children(struct device *dev, void *addrp)
+{
+        int result;
+
+        if (dev->type == &i2c_adapter_type)
+                result = device_for_each_child(dev, addrp,
+                                                i2c_check_mux_children);
+        else
+                result = __i2c_check_addr_busy(dev, addrp);
+
+        return result;
+}
+
 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 {
-        return device_for_each_child(&adapter->dev, &addr,
-                                     __i2c_check_addr_busy);
+        int result = 0;
+
+        if (i2c_parent_is_i2c_adapter(adapter))
+                result = i2c_check_mux_parents(
+                                    to_i2c_adapter(adapter->dev.parent), addr);
+
+        if (!result)
+                result = device_for_each_child(&adapter->dev, &addr,
+                                                i2c_check_mux_children);
+
+        return result;
+}
+
+/**
+ * i2c_lock_adapter - Get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+void i2c_lock_adapter(struct i2c_adapter *adapter)
+{
+        if (i2c_parent_is_i2c_adapter(adapter))
+                i2c_lock_adapter(to_i2c_adapter(adapter->dev.parent));
+        else
+                rt_mutex_lock(&adapter->bus_lock);
+}
+EXPORT_SYMBOL_GPL(i2c_lock_adapter);
+
+/**
+ * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+static int i2c_trylock_adapter(struct i2c_adapter *adapter)
+{
+        if (i2c_parent_is_i2c_adapter(adapter))
+                return i2c_trylock_adapter(to_i2c_adapter(adapter->dev.parent));
+        else
+                return rt_mutex_trylock(&adapter->bus_lock);
+}
+
+/**
+ * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+void i2c_unlock_adapter(struct i2c_adapter *adapter)
+{
+        if (i2c_parent_is_i2c_adapter(adapter))
+                i2c_unlock_adapter(to_i2c_adapter(adapter->dev.parent));
+        else
+                rt_mutex_unlock(&adapter->bus_lock);
 }
+EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
 
 /**
  * i2c_new_device - instantiate an i2c device
@@ -633,9 +711,9 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
                 return -EINVAL;
 
         /* Keep track of the added device */
-        i2c_lock_adapter(adap);
+        mutex_lock(&adap->userspace_clients_lock);
         list_add_tail(&client->detected, &adap->userspace_clients);
-        i2c_unlock_adapter(adap);
+        mutex_unlock(&adap->userspace_clients_lock);
         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
                  info.type, info.addr);
 
@@ -674,7 +752,7 @@ i2c_sysfs_delete_device(struct device