From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- drivers/i2c/i2c-mux.c | 466 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 466 insertions(+) create mode 100644 drivers/i2c/i2c-mux.c (limited to 'drivers/i2c/i2c-mux.c') diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c new file mode 100644 index 0000000000..57ff09f18c --- /dev/null +++ b/drivers/i2c/i2c-mux.c @@ -0,0 +1,466 @@ +/* + * Multiplexed I2C bus driver. + * + * Copyright (c) 2008-2009 Rodolfo Giometti + * Copyright (c) 2008-2009 Eurotech S.p.A. + * Copyright (c) 2009-2010 NSN GmbH & Co KG + * + * Simplifies access to complex multiplexed I2C bus topologies, by presenting + * each multiplexed bus segment as an additional I2C adapter. + * Supports multi-level mux'ing (mux behind a mux). + * + * Based on: + * i2c-virt.c from Kumar Gala + * i2c-virtual.c from Ken Harrenstien, Copyright (c) 2004 Google, Inc. + * i2c-virtual.c from Brian Kuschak + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +/* multiplexer per channel data */ +struct i2c_mux_priv { + struct i2c_adapter adap; + struct i2c_algorithm algo; + struct i2c_mux_core *muxc; + 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) +{ + 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_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 = __i2c_smbus_xfer(parent, addr, flags, + read_write, command, size, data); + 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 = i2c_smbus_xfer(parent, addr, flags, + read_write, command, size, data); + if (muxc->deselect) + muxc->deselect(muxc, priv->chan_id); + + return ret; +} + +/* Return the parent's functionality */ +static u32 i2c_mux_functionality(struct i2c_adapter *adap) +{ + struct i2c_mux_priv *priv = adap->algo_data; + struct i2c_adapter *parent = priv->muxc->parent; + + return parent->algo->functionality(parent); +} + +/* Return all parent classes, merged */ +static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent) +{ + unsigned int class = 0; + + do { + class |= parent->class; + parent = i2c_parent_is_i2c_adapter(parent); + } while (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_nested(&parent->mux_lock, i2c_adapter_depth(adapter)); + 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 (i2c_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; + + rt_mutex_lock_nested(&parent->mux_lock, i2c_adapter_depth(adapter)); + i2c_lock_bus(parent, flags); +} + +static int i2c_parent_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 (i2c_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, + unsigned int flags) +{ + struct i2c_mux_priv *priv = adapter->algo_data; + struct i2c_adapter *parent = priv->muxc->parent; + + 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, + int (*select)(struct i2c_mux_core *, u32), + int (*deselect)(struct i2c_mux_core *, u32)) +{ + struct i2c_mux_core *muxc; + size_t mux_size; + + mux_size = struct_size(muxc, adapter, max_adapters); + muxc = devm_kzalloc(dev, size_add(mux_size, sizeof_priv), GFP_KERNEL); + if (!muxc) + return NULL; + if (sizeof_priv) + muxc->priv = &muxc->adapter[max_adapters]; + + muxc->parent = parent; + muxc->dev = dev; + if (flags & I2C_MUX_LOCKED) + muxc->mux_locked = true; + if (flags & I2C_MUX_ARBITRATOR) + muxc->arbitrator = true; + if (flags & I2C_MUX_GATE) + muxc->gate = true; + muxc->select = select; + muxc->deselect = deselect; + muxc->max_adapters = max_adapters; + + return muxc; +} +EXPORT_SYMBOL_GPL(i2c_mux_alloc); + +static const struct i2c_lock_operations i2c_mux_lock_ops = { + .lock_bus = i2c_mux_lock_bus, + .trylock_bus = i2c_mux_trylock_bus, + .unlock_bus = i2c_mux_unlock_bus, +}; + +static const struct i2c_lock_operations i2c_parent_lock_ops = { + .lock_bus = i2c_parent_lock_bus, + .trylock_bus = i2c_parent_trylock_bus, + .unlock_bus = i2c_parent_unlock_bus, +}; + +int i2c_mux_add_adapter(struct i2c_mux_core *muxc, + u32 force_nr, u32 chan_id, + unsigned int class) +{ + struct i2c_adapter *parent = muxc->parent; + struct i2c_mux_priv *priv; + char symlink_name[20]; + int ret; + + if (muxc->num_adapters >= muxc->max_adapters) { + dev_err(muxc->dev, "No room for more i2c-mux adapters\n"); + return -EINVAL; + } + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + /* Set up private adapter data */ + priv->muxc = muxc; + priv->chan_id = chan_id; + + /* 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) { + if (muxc->mux_locked) + priv->algo.master_xfer = i2c_mux_master_xfer; + else + priv->algo.master_xfer = __i2c_mux_master_xfer; + } + if (parent->algo->master_xfer_atomic) + priv->algo.master_xfer_atomic = priv->algo.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; + } + if (parent->algo->smbus_xfer_atomic) + priv->algo.smbus_xfer_atomic = priv->algo.smbus_xfer; + + priv->algo.functionality = i2c_mux_functionality; + + /* Now fill out new adapter structure */ + snprintf(priv->adap.name, sizeof(priv->adap.name), + "i2c-%d-mux (chan_id %d)", i2c_adapter_id(parent), chan_id); + priv->adap.owner = THIS_MODULE; + priv->adap.algo = &priv->algo; + priv->adap.algo_data = priv; + priv->adap.dev.parent = &parent->dev; + priv->adap.retries = parent->retries; + priv->adap.timeout = parent->timeout; + priv->adap.quirks = parent->quirks; + if (muxc->mux_locked) + priv->adap.lock_ops = &i2c_mux_lock_ops; + else + priv->adap.lock_ops = &i2c_parent_lock_ops; + + /* Sanity check on class */ + if (i2c_mux_parent_classes(parent) & class & ~I2C_CLASS_DEPRECATED) + dev_err(&parent->dev, + "Segment %d behind mux can't share classes with ancestors\n", + chan_id); + else + priv->adap.class = class; + + /* + * Try to populate the mux adapter's of_node, expands to + * nothing if !CONFIG_OF. + */ + if (muxc->dev->of_node) { + struct device_node *dev_node = muxc->dev->of_node; + struct device_node *mux_node, *child = NULL; + u32 reg; + + if (muxc->arbitrator) + mux_node = of_get_child_by_name(dev_node, "i2c-arb"); + else if (muxc->gate) + mux_node = of_get_child_by_name(dev_node, "i2c-gate"); + else + mux_node = of_get_child_by_name(dev_node, "i2c-mux"); + + if (mux_node) { + /* A "reg" property indicates an old-style DT entry */ + if (!of_property_read_u32(mux_node, "reg", ®)) { + of_node_put(mux_node); + mux_node = NULL; + } + } + + if (!mux_node) + mux_node = of_node_get(dev_node); + else if (muxc->arbitrator || muxc->gate) + child = of_node_get(mux_node); + + if (!child) { + for_each_child_of_node(mux_node, child) { + ret = of_property_read_u32(child, "reg", ®); + if (ret) + continue; + if (chan_id == reg) + break; + } + } + + priv->adap.dev.of_node = child; + of_node_put(mux_node); + } + + /* + * Associate the mux channel with an ACPI node. + */ + if (has_acpi_companion(muxc->dev)) + acpi_preset_companion(&priv->adap.dev, + ACPI_COMPANION(muxc->dev), + chan_id); + + if (force_nr) { + priv->adap.nr = force_nr; + ret = i2c_add_numbered_adapter(&priv->adap); + if (ret < 0) { + dev_err(&parent->dev, + "failed to add mux-adapter %u as bus %u (error=%d)\n", + chan_id, force_nr, ret); + goto err_free_priv; + } + } else { + ret = i2c_add_adapter(&priv->adap); + if (ret < 0) { + dev_err(&parent->dev, + "failed to add mux-adapter %u (error=%d)\n", + chan_id, ret); + goto err_free_priv; + } + } + + WARN(sysfs_create_link(&priv->adap.dev.kobj, &muxc->dev->kobj, + "mux_device"), + "can't create symlink to mux device\n"); + + snprintf(symlink_name, sizeof(symlink_name), "channel-%u", chan_id); + WARN(sysfs_create_link(&muxc->dev->kobj, &priv->adap.dev.kobj, + symlink_name), + "can't create symlink to channel %u\n", chan_id); + dev_info(&parent->dev, "Added multiplexed i2c bus %d\n", + i2c_adapter_id(&priv->adap)); + + muxc->adapter[muxc->num_adapters++] = &priv->adap; + return 0; + +err_free_priv: + kfree(priv); + return ret; +} +EXPORT_SYMBOL_GPL(i2c_mux_add_adapter); + +void i2c_mux_del_adapters(struct i2c_mux_core *muxc) +{ + char symlink_name[20]; + + while (muxc->num_adapters) { + struct i2c_adapter *adap = muxc->adapter[--muxc->num_adapters]; + struct i2c_mux_priv *priv = adap->algo_data; + struct device_node *np = adap->dev.of_node; + + muxc->adapter[muxc->num_adapters] = NULL; + + snprintf(symlink_name, sizeof(symlink_name), + "channel-%u", priv->chan_id); + sysfs_remove_link(&muxc->dev->kobj, symlink_name); + + sysfs_remove_link(&priv->adap.dev.kobj, "mux_device"); + i2c_del_adapter(adap); + of_node_put(np); + kfree(priv); + } +} +EXPORT_SYMBOL_GPL(i2c_mux_del_adapters); + +MODULE_AUTHOR("Rodolfo Giometti "); +MODULE_DESCRIPTION("I2C driver for multiplexed I2C busses"); +MODULE_LICENSE("GPL v2"); -- cgit v1.2.3