summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--drivers/i2c/i2c-core.c41
-rw-r--r--include/linux/i2c.h44
2 files changed, 69 insertions, 16 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 4979728f7fb2..7ef5bd085476 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -954,10 +954,13 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
}
/**
- * i2c_lock_adapter - Get exclusive access to an I2C bus segment
+ * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
* @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
+ * locks only this branch in the adapter tree
*/
-void i2c_lock_adapter(struct i2c_adapter *adapter)
+static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
+ unsigned int flags)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
@@ -966,27 +969,32 @@ void i2c_lock_adapter(struct i2c_adapter *adapter)
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
+ * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
* @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
+ * trylocks only this branch in the adapter tree
*/
-static int i2c_trylock_adapter(struct i2c_adapter *adapter)
+static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
+ unsigned int flags)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
if (parent)
- return i2c_trylock_adapter(parent);
+ return parent->trylock_bus(parent, flags);
else
return rt_mutex_trylock(&adapter->bus_lock);
}
/**
- * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
+ * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
* @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
+ * unlocks only this branch in the adapter tree
*/
-void i2c_unlock_adapter(struct i2c_adapter *adapter)
+static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
+ unsigned int flags)
{
struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
@@ -995,7 +1003,6 @@ void i2c_unlock_adapter(struct i2c_adapter *adapter)
else
rt_mutex_unlock(&adapter->bus_lock);
}
-EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
static void i2c_dev_set_name(struct i2c_adapter *adap,
struct i2c_client *client)
@@ -1541,6 +1548,12 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
return -EINVAL;
}
+ if (!adap->lock_bus) {
+ adap->lock_bus = i2c_adapter_lock_bus;
+ adap->trylock_bus = i2c_adapter_trylock_bus;
+ adap->unlock_bus = i2c_adapter_unlock_bus;
+ }
+
rt_mutex_init(&adap->bus_lock);
mutex_init(&adap->userspace_clients_lock);
INIT_LIST_HEAD(&adap->userspace_clients);
@@ -2310,16 +2323,16 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
#endif
if (in_atomic() || irqs_disabled()) {
- ret = i2c_trylock_adapter(adap);
+ ret = adap->trylock_bus(adap, I2C_LOCK_SEGMENT);
if (!ret)
/* I2C activity is ongoing. */
return -EAGAIN;
} else {
- i2c_lock_adapter(adap);
+ i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
}
ret = __i2c_transfer(adap, msgs, num);
- i2c_unlock_adapter(adap);
+ i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
return ret;
} else {
@@ -3094,7 +3107,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
if (adapter->algo->smbus_xfer) {
- i2c_lock_adapter(adapter);
+ i2c_lock_bus(adapter, I2C_LOCK_SEGMENT);
/* Retry automatically on arbitration loss */
orig_jiffies = jiffies;
@@ -3108,7 +3121,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
orig_jiffies + adapter->timeout))
break;
}
- i2c_unlock_adapter(adapter);
+ i2c_unlock_bus(adapter, I2C_LOCK_SEGMENT);
if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
goto trace;
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index c30833b7b073..50934d6e1050 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -538,6 +538,10 @@ struct i2c_adapter {
struct i2c_bus_recovery_info *bus_recovery_info;
const struct i2c_adapter_quirks *quirks;
+
+ void (*lock_bus)(struct i2c_adapter *, unsigned int flags);
+ int (*trylock_bus)(struct i2c_adapter *, unsigned int flags);
+ void (*unlock_bus)(struct i2c_adapter *, unsigned int flags);
};
#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
@@ -567,8 +571,44 @@ i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
/* Adapter locking functions, exported for shared pin cases */
-void i2c_lock_adapter(struct i2c_adapter *);
-void i2c_unlock_adapter(struct i2c_adapter *);
+#define I2C_LOCK_ROOT_ADAPTER BIT(0)
+#define I2C_LOCK_SEGMENT BIT(1)
+
+/**
+ * i2c_lock_bus - Get exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
+ * locks only this branch in the adapter tree
+ */
+static inline void
+i2c_lock_bus(struct i2c_adapter *adapter, unsigned int flags)
+{
+ adapter->lock_bus(adapter, flags);
+}
+
+/**
+ * i2c_unlock_bus - Release exclusive access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
+ * unlocks only this branch in the adapter tree
+ */
+static inline void
+i2c_unlock_bus(struct i2c_adapter *adapter, unsigned int flags)
+{
+ adapter->unlock_bus(adapter, flags);
+}
+
+static inline void
+i2c_lock_adapter(struct i2c_adapter *adapter)
+{
+ i2c_lock_bus(adapter, I2C_LOCK_ROOT_ADAPTER);
+}
+
+static inline void
+i2c_unlock_adapter(struct i2c_adapter *adapter)
+{
+ i2c_unlock_bus(adapter, I2C_LOCK_ROOT_ADAPTER);
+}
/*flags for the client struct: */
#define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */