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i2c: Multiplexed I2C bus core support

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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>
This commit is contained in:
Michael Lawnick
2010-08-11 18:21:02 +02:00
committed by Jean Delvare
parent dafc50d141
commit 0826374bff
7 changed files with 327 additions and 8 deletions
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64
drivers/i2c/i2c-core.c
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@ -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;