diff options
Diffstat (limited to 'drivers/i2c/i2c-mux.c')
| -rw-r--r-- | drivers/i2c/i2c-mux.c | 152 |
1 files changed, 139 insertions, 13 deletions
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c index 5fa8af715e24..8eee98634cda 100644 --- a/drivers/i2c/i2c-mux.c +++ b/drivers/i2c/i2c-mux.c @@ -35,6 +35,25 @@ struct i2c_mux_priv { u32 chan_id; }; +static int __i2c_mux_master_xfer(struct i2c_adapter *adap, + struct i2c_msg msgs[], int num) +{ + struct i2c_mux_priv *priv = adap->algo_data; + struct i2c_mux_core *muxc = priv->muxc; + struct i2c_adapter *parent = muxc->parent; + int ret; + + /* Switch to the right mux port and perform the transfer. */ + + ret = muxc->select(muxc, priv->chan_id); + if (ret >= 0) + ret = __i2c_transfer(parent, msgs, num); + if (muxc->deselect) + muxc->deselect(muxc, priv->chan_id); + + return ret; +} + static int i2c_mux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) { @@ -47,7 +66,29 @@ static int i2c_mux_master_xfer(struct i2c_adapter *adap, ret = muxc->select(muxc, priv->chan_id); if (ret >= 0) - ret = __i2c_transfer(parent, msgs, num); + ret = i2c_transfer(parent, msgs, num); + if (muxc->deselect) + muxc->deselect(muxc, priv->chan_id); + + return ret; +} + +static int __i2c_mux_smbus_xfer(struct i2c_adapter *adap, + u16 addr, unsigned short flags, + char read_write, u8 command, + int size, union i2c_smbus_data *data) +{ + struct i2c_mux_priv *priv = adap->algo_data; + struct i2c_mux_core *muxc = priv->muxc; + struct i2c_adapter *parent = muxc->parent; + int ret; + + /* Select the right mux port and perform the transfer. */ + + ret = muxc->select(muxc, priv->chan_id); + if (ret >= 0) + ret = parent->algo->smbus_xfer(parent, addr, flags, + read_write, command, size, data); if (muxc->deselect) muxc->deselect(muxc, priv->chan_id); @@ -68,8 +109,8 @@ static int i2c_mux_smbus_xfer(struct i2c_adapter *adap, ret = muxc->select(muxc, priv->chan_id); if (ret >= 0) - ret = parent->algo->smbus_xfer(parent, addr, flags, - read_write, command, size, data); + ret = i2c_smbus_xfer(parent, addr, flags, + read_write, command, size, data); if (muxc->deselect) muxc->deselect(muxc, priv->chan_id); @@ -98,13 +139,50 @@ static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent) return class; } +static void i2c_mux_lock_bus(struct i2c_adapter *adapter, unsigned int flags) +{ + struct i2c_mux_priv *priv = adapter->algo_data; + struct i2c_adapter *parent = priv->muxc->parent; + + rt_mutex_lock(&parent->mux_lock); + if (!(flags & I2C_LOCK_ROOT_ADAPTER)) + return; + i2c_lock_bus(parent, flags); +} + +static int i2c_mux_trylock_bus(struct i2c_adapter *adapter, unsigned int flags) +{ + struct i2c_mux_priv *priv = adapter->algo_data; + struct i2c_adapter *parent = priv->muxc->parent; + + if (!rt_mutex_trylock(&parent->mux_lock)) + return 0; /* mux_lock not locked, failure */ + if (!(flags & I2C_LOCK_ROOT_ADAPTER)) + return 1; /* we only want mux_lock, success */ + if (parent->trylock_bus(parent, flags)) + return 1; /* parent locked too, success */ + rt_mutex_unlock(&parent->mux_lock); + return 0; /* parent not locked, failure */ +} + +static void i2c_mux_unlock_bus(struct i2c_adapter *adapter, unsigned int flags) +{ + struct i2c_mux_priv *priv = adapter->algo_data; + struct i2c_adapter *parent = priv->muxc->parent; + + if (flags & I2C_LOCK_ROOT_ADAPTER) + i2c_unlock_bus(parent, flags); + rt_mutex_unlock(&parent->mux_lock); +} + static void i2c_parent_lock_bus(struct i2c_adapter *adapter, unsigned int flags) { struct i2c_mux_priv *priv = adapter->algo_data; struct i2c_adapter *parent = priv->muxc->parent; - parent->lock_bus(parent, flags); + rt_mutex_lock(&parent->mux_lock); + i2c_lock_bus(parent, flags); } static int i2c_parent_trylock_bus(struct i2c_adapter *adapter, @@ -113,7 +191,12 @@ static int i2c_parent_trylock_bus(struct i2c_adapter *adapter, struct i2c_mux_priv *priv = adapter->algo_data; struct i2c_adapter *parent = priv->muxc->parent; - return parent->trylock_bus(parent, flags); + if (!rt_mutex_trylock(&parent->mux_lock)) + return 0; /* mux_lock not locked, failure */ + if (parent->trylock_bus(parent, flags)) + return 1; /* parent locked too, success */ + rt_mutex_unlock(&parent->mux_lock); + return 0; /* parent not locked, failure */ } static void i2c_parent_unlock_bus(struct i2c_adapter *adapter, @@ -122,9 +205,36 @@ static void i2c_parent_unlock_bus(struct i2c_adapter *adapter, struct i2c_mux_priv *priv = adapter->algo_data; struct i2c_adapter *parent = priv->muxc->parent; - parent->unlock_bus(parent, flags); + i2c_unlock_bus(parent, flags); + rt_mutex_unlock(&parent->mux_lock); } +struct i2c_adapter *i2c_root_adapter(struct device *dev) +{ + struct device *i2c; + struct i2c_adapter *i2c_root; + + /* + * Walk up the device tree to find an i2c adapter, indicating + * that this is an i2c client device. Check all ancestors to + * handle mfd devices etc. + */ + for (i2c = dev; i2c; i2c = i2c->parent) { + if (i2c->type == &i2c_adapter_type) + break; + } + if (!i2c) + return NULL; + + /* Continue up the tree to find the root i2c adapter */ + i2c_root = to_i2c_adapter(i2c); + while (i2c_parent_is_i2c_adapter(i2c_root)) + i2c_root = i2c_parent_is_i2c_adapter(i2c_root); + + return i2c_root; +} +EXPORT_SYMBOL_GPL(i2c_root_adapter); + struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, struct device *dev, int max_adapters, int sizeof_priv, u32 flags, @@ -143,6 +253,8 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, muxc->parent = parent; muxc->dev = dev; + if (flags & I2C_MUX_LOCKED) + muxc->mux_locked = true; muxc->select = select; muxc->deselect = deselect; muxc->max_adapters = max_adapters; @@ -176,10 +288,18 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc, /* Need to do algo dynamically because we don't know ahead * of time what sort of physical adapter we'll be dealing with. */ - if (parent->algo->master_xfer) - priv->algo.master_xfer = i2c_mux_master_xfer; - if (parent->algo->smbus_xfer) - priv->algo.smbus_xfer = i2c_mux_smbus_xfer; + if (parent->algo->master_xfer) { + if (muxc->mux_locked) + priv->algo.master_xfer = i2c_mux_master_xfer; + else + priv->algo.master_xfer = __i2c_mux_master_xfer; + } + if (parent->algo->smbus_xfer) { + if (muxc->mux_locked) + priv->algo.smbus_xfer = i2c_mux_smbus_xfer; + else + priv->algo.smbus_xfer = __i2c_mux_smbus_xfer; + } priv->algo.functionality = i2c_mux_functionality; /* Now fill out new adapter structure */ @@ -192,9 +312,15 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc, priv->adap.retries = parent->retries; priv->adap.timeout = parent->timeout; priv->adap.quirks = parent->quirks; - priv->adap.lock_bus = i2c_parent_lock_bus; - priv->adap.trylock_bus = i2c_parent_trylock_bus; - priv->adap.unlock_bus = i2c_parent_unlock_bus; + if (muxc->mux_locked) { + priv->adap.lock_bus = i2c_mux_lock_bus; + priv->adap.trylock_bus = i2c_mux_trylock_bus; + priv->adap.unlock_bus = i2c_mux_unlock_bus; + } else { + priv->adap.lock_bus = i2c_parent_lock_bus; + priv->adap.trylock_bus = i2c_parent_trylock_bus; + priv->adap.unlock_bus = i2c_parent_unlock_bus; + } /* Sanity check on class */ if (i2c_mux_parent_classes(parent) & class) |