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authorMichael Lawnick <ml.lawnick@gmx.de>2010-08-11 18:21:02 +0200
committerJean Delvare <khali@linux-fr.org>2010-08-11 18:21:02 +0200
commit0826374bff57411d239f2fcb15da3c35af0a93cd (patch)
tree514d4361cfc9cc546306612de3464def7fe8a7cd /drivers/i2c/i2c-core.c
parentdafc50d141c27959dbd3a1cfe9857a86d23402a7 (diff)
i2c: Multiplexed I2C bus core support
Add multiplexed bus core support. I2C multiplexer and switches like pca954x get instantiated as new adapters per port. Signed-off-by: Michael Lawnick <ml.lawnick@gmx.de> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/i2c/i2c-core.c')
-rw-r--r--drivers/i2c/i2c-core.c64
1 files changed, 57 insertions, 7 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 97f96b66653c..6649176de940 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>
@@ -423,10 +425,48 @@ 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;
}
/**
@@ -435,7 +475,10 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
*/
void i2c_lock_adapter(struct i2c_adapter *adapter)
{
- rt_mutex_lock(&adapter->bus_lock);
+ 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);
@@ -445,7 +488,10 @@ EXPORT_SYMBOL_GPL(i2c_lock_adapter);
*/
static int i2c_trylock_adapter(struct i2c_adapter *adapter)
{
- return rt_mutex_trylock(&adapter->bus_lock);
+ 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);
}
/**
@@ -454,7 +500,10 @@ static int i2c_trylock_adapter(struct i2c_adapter *adapter)
*/
void i2c_unlock_adapter(struct i2c_adapter *adapter)
{
- rt_mutex_unlock(&adapter->bus_lock);
+ 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);
@@ -743,10 +792,11 @@ static const struct attribute_group *i2c_adapter_attr_groups[] = {
NULL
};
-static struct device_type i2c_adapter_type = {
+struct device_type i2c_adapter_type = {
.groups = i2c_adapter_attr_groups,
.release = i2c_adapter_dev_release,
};
+EXPORT_SYMBOL_GPL(i2c_adapter_type);
#ifdef CONFIG_I2C_COMPAT
static struct class_compat *i2c_adapter_compat_class;