From a7ab72390b77062420fb50e4451f71c9321aae05 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Wed, 20 Apr 2016 08:38:50 +0200 Subject: i2c: mux: add common data for every i2c-mux instance All i2c-muxes have a parent adapter and one or many child adapters. A mux also has some means of selection. Previously, this was stored per child adapter, but it is only needed to keep track of this per mux. Add an i2c mux core, that keeps track of this consistently. Also add some glue for users of the old interface, which will create one implicit mux core per child adapter. Signed-off-by: Peter Rosin Tested-by: Antti Palosaari Tested-by: Crestez Dan Leonard Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-mux.c | 175 ++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 134 insertions(+), 41 deletions(-) (limited to 'drivers/i2c/i2c-mux.c') diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c index d4022878b2f0..5ce1b0704cb5 100644 --- a/drivers/i2c/i2c-mux.c +++ b/drivers/i2c/i2c-mux.c @@ -28,33 +28,34 @@ #include /* multiplexer per channel data */ +struct i2c_mux_priv_old { + void *mux_priv; + int (*select)(struct i2c_adapter *, void *mux_priv, u32 chan_id); + int (*deselect)(struct i2c_adapter *, void *mux_priv, u32 chan_id); +}; + struct i2c_mux_priv { struct i2c_adapter adap; struct i2c_algorithm algo; - - struct i2c_adapter *parent; - struct device *mux_dev; - void *mux_priv; + struct i2c_mux_core *muxc; u32 chan_id; - - int (*select)(struct i2c_adapter *, void *mux_priv, u32 chan_id); - int (*deselect)(struct i2c_adapter *, void *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_adapter *parent = priv->parent; + 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 = priv->select(parent, priv->mux_priv, priv->chan_id); + ret = muxc->select(muxc, priv->chan_id); if (ret >= 0) ret = __i2c_transfer(parent, msgs, num); - if (priv->deselect) - priv->deselect(parent, priv->mux_priv, priv->chan_id); + if (muxc->deselect) + muxc->deselect(muxc, priv->chan_id); return ret; } @@ -65,17 +66,18 @@ static int i2c_mux_smbus_xfer(struct i2c_adapter *adap, int size, union i2c_smbus_data *data) { struct i2c_mux_priv *priv = adap->algo_data; - struct i2c_adapter *parent = priv->parent; + 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 = priv->select(parent, priv->mux_priv, priv->chan_id); + ret = muxc->select(muxc, priv->chan_id); if (ret >= 0) ret = parent->algo->smbus_xfer(parent, addr, flags, read_write, command, size, data); - if (priv->deselect) - priv->deselect(parent, priv->mux_priv, priv->chan_id); + if (muxc->deselect) + muxc->deselect(muxc, priv->chan_id); return ret; } @@ -84,7 +86,7 @@ static int i2c_mux_smbus_xfer(struct i2c_adapter *adap, static u32 i2c_mux_functionality(struct i2c_adapter *adap) { struct i2c_mux_priv *priv = adap->algo_data; - struct i2c_adapter *parent = priv->parent; + struct i2c_adapter *parent = priv->muxc->parent; return parent->algo->functionality(parent); } @@ -102,6 +104,20 @@ static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent) return class; } +static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan) +{ + struct i2c_mux_priv_old *priv = i2c_mux_priv(muxc); + + return priv->select(muxc->parent, priv->mux_priv, chan); +} + +static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan) +{ + struct i2c_mux_priv_old *priv = i2c_mux_priv(muxc); + + return priv->deselect(muxc->parent, priv->mux_priv, chan); +} + struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, struct device *mux_dev, void *mux_priv, u32 force_nr, u32 chan_id, @@ -111,21 +127,77 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, int (*deselect) (struct i2c_adapter *, void *, u32)) { + struct i2c_mux_core *muxc; + struct i2c_mux_priv_old *priv; + int ret; + + muxc = i2c_mux_alloc(parent, mux_dev, 1, sizeof(*priv), 0, + i2c_mux_select, i2c_mux_deselect); + if (!muxc) + return NULL; + + priv = i2c_mux_priv(muxc); + priv->select = select; + priv->deselect = deselect; + priv->mux_priv = mux_priv; + + ret = i2c_mux_add_adapter(muxc, force_nr, chan_id, class); + if (ret) { + devm_kfree(mux_dev, muxc); + return NULL; + } + + return muxc->adapter[0]; +} +EXPORT_SYMBOL_GPL(i2c_add_mux_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; + + muxc = devm_kzalloc(dev, sizeof(*muxc) + + max_adapters * sizeof(muxc->adapter[0]) + + sizeof_priv, GFP_KERNEL); + if (!muxc) + return NULL; + if (sizeof_priv) + muxc->priv = &muxc->adapter[max_adapters]; + + muxc->parent = parent; + muxc->dev = dev; + muxc->select = select; + muxc->deselect = deselect; + muxc->max_adapters = max_adapters; + + return muxc; +} +EXPORT_SYMBOL_GPL(i2c_mux_alloc); + +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; - priv = kzalloc(sizeof(struct i2c_mux_priv), GFP_KERNEL); + 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 NULL; + return -ENOMEM; /* Set up private adapter data */ - priv->parent = parent; - priv->mux_dev = mux_dev; - priv->mux_priv = mux_priv; + priv->muxc = muxc; priv->chan_id = chan_id; - priv->select = select; - priv->deselect = deselect; /* Need to do algo dynamically because we don't know ahead * of time what sort of physical adapter we'll be dealing with. @@ -159,11 +231,11 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, * Try to populate the mux adapter's of_node, expands to * nothing if !CONFIG_OF. */ - if (mux_dev->of_node) { + if (muxc->dev->of_node) { struct device_node *child; u32 reg; - for_each_child_of_node(mux_dev->of_node, child) { + for_each_child_of_node(muxc->dev->of_node, child) { ret = of_property_read_u32(child, "reg", ®); if (ret) continue; @@ -177,8 +249,9 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, /* * Associate the mux channel with an ACPI node. */ - if (has_acpi_companion(mux_dev)) - acpi_preset_companion(&priv->adap.dev, ACPI_COMPANION(mux_dev), + if (has_acpi_companion(muxc->dev)) + acpi_preset_companion(&priv->adap.dev, + ACPI_COMPANION(muxc->dev), chan_id); if (force_nr) { @@ -192,33 +265,53 @@ struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, "failed to add mux-adapter (error=%d)\n", ret); kfree(priv); - return NULL; + return ret; } - WARN(sysfs_create_link(&priv->adap.dev.kobj, &mux_dev->kobj, "mux_device"), - "can't create symlink to mux device\n"); + 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(&mux_dev->kobj, &priv->adap.dev.kobj, symlink_name), - "can't create symlink for channel %u\n", chan_id); + WARN(sysfs_create_link(&muxc->dev->kobj, &priv->adap.dev.kobj, + symlink_name), + "can't create symlink for channel %u\n", chan_id); dev_info(&parent->dev, "Added multiplexed i2c bus %d\n", i2c_adapter_id(&priv->adap)); - return &priv->adap; + muxc->adapter[muxc->num_adapters++] = &priv->adap; + return 0; } -EXPORT_SYMBOL_GPL(i2c_add_mux_adapter); +EXPORT_SYMBOL_GPL(i2c_mux_add_adapter); -void i2c_del_mux_adapter(struct i2c_adapter *adap) +void i2c_mux_del_adapters(struct i2c_mux_core *muxc) { - struct i2c_mux_priv *priv = adap->algo_data; char symlink_name[20]; - snprintf(symlink_name, sizeof(symlink_name), "channel-%u", priv->chan_id); - sysfs_remove_link(&priv->mux_dev->kobj, symlink_name); + while (muxc->num_adapters) { + struct i2c_adapter *adap = muxc->adapter[--muxc->num_adapters]; + struct i2c_mux_priv *priv = adap->algo_data; + + 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); + kfree(priv); + } +} +EXPORT_SYMBOL_GPL(i2c_mux_del_adapters); + +void i2c_del_mux_adapter(struct i2c_adapter *adap) +{ + struct i2c_mux_priv *priv = adap->algo_data; + struct i2c_mux_core *muxc = priv->muxc; - sysfs_remove_link(&priv->adap.dev.kobj, "mux_device"); - i2c_del_adapter(adap); - kfree(priv); + i2c_mux_del_adapters(muxc); + devm_kfree(muxc->dev, muxc); } EXPORT_SYMBOL_GPL(i2c_del_mux_adapter); -- cgit v1.2.3 From 23fe440c59b9f08afe108e7ec7b6714cb2a3b955 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Wed, 2 Mar 2016 15:14:22 +0100 Subject: i2c: mux: drop old unused i2c-mux api All i2c mux users are using an explicit i2c mux core, drop support for implicit i2c mux cores. Signed-off-by: Peter Rosin Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-mux.c | 63 ------------------------------------------------- include/linux/i2c-mux.h | 15 ------------ 2 files changed, 78 deletions(-) (limited to 'drivers/i2c/i2c-mux.c') diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c index 5ce1b0704cb5..25e9336b0e6e 100644 --- a/drivers/i2c/i2c-mux.c +++ b/drivers/i2c/i2c-mux.c @@ -28,12 +28,6 @@ #include /* multiplexer per channel data */ -struct i2c_mux_priv_old { - void *mux_priv; - int (*select)(struct i2c_adapter *, void *mux_priv, u32 chan_id); - int (*deselect)(struct i2c_adapter *, void *mux_priv, u32 chan_id); -}; - struct i2c_mux_priv { struct i2c_adapter adap; struct i2c_algorithm algo; @@ -104,53 +98,6 @@ static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent) return class; } -static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan) -{ - struct i2c_mux_priv_old *priv = i2c_mux_priv(muxc); - - return priv->select(muxc->parent, priv->mux_priv, chan); -} - -static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan) -{ - struct i2c_mux_priv_old *priv = i2c_mux_priv(muxc); - - return priv->deselect(muxc->parent, priv->mux_priv, chan); -} - -struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, - struct device *mux_dev, - void *mux_priv, u32 force_nr, u32 chan_id, - unsigned int class, - int (*select) (struct i2c_adapter *, - void *, u32), - int (*deselect) (struct i2c_adapter *, - void *, u32)) -{ - struct i2c_mux_core *muxc; - struct i2c_mux_priv_old *priv; - int ret; - - muxc = i2c_mux_alloc(parent, mux_dev, 1, sizeof(*priv), 0, - i2c_mux_select, i2c_mux_deselect); - if (!muxc) - return NULL; - - priv = i2c_mux_priv(muxc); - priv->select = select; - priv->deselect = deselect; - priv->mux_priv = mux_priv; - - ret = i2c_mux_add_adapter(muxc, force_nr, chan_id, class); - if (ret) { - devm_kfree(mux_dev, muxc); - return NULL; - } - - return muxc->adapter[0]; -} -EXPORT_SYMBOL_GPL(i2c_add_mux_adapter); - struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, struct device *dev, int max_adapters, int sizeof_priv, u32 flags, @@ -305,16 +252,6 @@ void i2c_mux_del_adapters(struct i2c_mux_core *muxc) } EXPORT_SYMBOL_GPL(i2c_mux_del_adapters); -void i2c_del_mux_adapter(struct i2c_adapter *adap) -{ - struct i2c_mux_priv *priv = adap->algo_data; - struct i2c_mux_core *muxc = priv->muxc; - - i2c_mux_del_adapters(muxc); - devm_kfree(muxc->dev, muxc); -} -EXPORT_SYMBOL_GPL(i2c_del_mux_adapter); - MODULE_AUTHOR("Rodolfo Giometti "); MODULE_DESCRIPTION("I2C driver for multiplexed I2C busses"); MODULE_LICENSE("GPL v2"); diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h index 71ac1b3f4f68..2fa93fe1345e 100644 --- a/include/linux/i2c-mux.h +++ b/include/linux/i2c-mux.h @@ -52,20 +52,6 @@ static inline void *i2c_mux_priv(struct i2c_mux_core *muxc) return muxc->priv; } -/* - * Called to create a i2c bus on a multiplexed bus segment. - * The mux_dev and chan_id parameters are passed to the select - * and deselect callback functions to perform hardware-specific - * mux control. - */ -struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent, - struct device *mux_dev, - void *mux_priv, u32 force_nr, u32 chan_id, - unsigned int class, - int (*select) (struct i2c_adapter *, - void *mux_dev, u32 chan_id), - int (*deselect) (struct i2c_adapter *, - void *mux_dev, u32 chan_id)); /* * Called to create an i2c bus on a multiplexed bus segment. * The chan_id parameter is passed to the select and deselect @@ -75,7 +61,6 @@ int i2c_mux_add_adapter(struct i2c_mux_core *muxc, u32 force_nr, u32 chan_id, unsigned int class); -void i2c_del_mux_adapter(struct i2c_adapter *adap); void i2c_mux_del_adapters(struct i2c_mux_core *muxc); #endif /* __KERNEL__ */ -- cgit v1.2.3 From fa96f0cb9b37a1a296d18f7bde63b0910852303e Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Wed, 4 May 2016 22:15:28 +0200 Subject: i2c: muxes always lock the parent adapter Instead of checking for i2c parent adapters for every lock/unlock, simply override the locking for muxes to always lock/unlock the parent adapter directly. Signed-off-by: Peter Rosin Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core.c | 21 +++------------------ drivers/i2c/i2c-mux.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 33 insertions(+), 18 deletions(-) (limited to 'drivers/i2c/i2c-mux.c') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 7ef5bd085476..afdee66002db 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -962,12 +962,7 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, unsigned int flags) { - struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); - - if (parent) - i2c_lock_adapter(parent); - else - rt_mutex_lock(&adapter->bus_lock); + rt_mutex_lock(&adapter->bus_lock); } /** @@ -979,12 +974,7 @@ static void i2c_adapter_lock_bus(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 parent->trylock_bus(parent, flags); - else - return rt_mutex_trylock(&adapter->bus_lock); + return rt_mutex_trylock(&adapter->bus_lock); } /** @@ -996,12 +986,7 @@ static int i2c_adapter_trylock_bus(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); - - if (parent) - i2c_unlock_adapter(parent); - else - rt_mutex_unlock(&adapter->bus_lock); + rt_mutex_unlock(&adapter->bus_lock); } static void i2c_dev_set_name(struct i2c_adapter *adap, diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c index 25e9336b0e6e..5fa8af715e24 100644 --- a/drivers/i2c/i2c-mux.c +++ b/drivers/i2c/i2c-mux.c @@ -98,6 +98,33 @@ static unsigned int i2c_mux_parent_classes(struct i2c_adapter *parent) return class; } +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); +} + +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; + + return parent->trylock_bus(parent, flags); +} + +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; + + parent->unlock_bus(parent, flags); +} + struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, struct device *dev, int max_adapters, int sizeof_priv, u32 flags, @@ -165,6 +192,9 @@ 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; /* Sanity check on class */ if (i2c_mux_parent_classes(parent) & class) -- cgit v1.2.3 From 6ef91fcca8a8ba3df9810a4cc6cd6a9d3f21bf45 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Wed, 4 May 2016 22:15:29 +0200 Subject: i2c: mux: relax locking of the top i2c adapter during mux-locked muxing With a i2c topology like the following GPIO ---| ------ BAT1 | v / I2C -----+----------+---- MUX | \ EEPROM ------ BAT2 there is a locking problem with the GPIO controller since it is a client on the same i2c bus that it muxes. Transfers to the mux clients (e.g. BAT1) will lock the whole i2c bus prior to attempting to switch the mux to the correct i2c segment. In the above case, the GPIO device is an I/O expander with an i2c interface, and since the GPIO subsystem knows nothing (and rightfully so) about the lockless needs of the i2c mux code, this results in a deadlock when the GPIO driver issues i2c transfers to modify the mux. So, observing that while it is needed to have the i2c bus locked during the actual MUX update in order to avoid random garbage on the slave side, it is not strictly a must to have it locked over the whole sequence of a full select-transfer-deselect mux client operation. The mux itself needs to be locked, so transfers to clients behind the mux are serialized, and the mux needs to be stable during all i2c traffic (otherwise individual mux slave segments might see garbage, or worse). Introduce this new locking concept as "mux-locked" muxes, and call the pre-existing mux locking scheme "parent-locked". Modify the i2c mux locking so that muxes that are "mux-locked" locks only the muxes on the parent adapter instead of the whole i2c bus when there is a transfer to the slave side of the mux. This lock serializes transfers to the slave side of the muxes on the parent adapter. Add code to i2c-mux-gpio and i2c-mux-pinctrl that checks if all involved gpio/pinctrl devices have a parent that is an i2c adapter in the same adapter tree that is muxed, and request a "mux-locked mux" if that is the case. Modify the select-transfer-deselect code for "mux-locked" muxes so that each of the select-transfer-deselect ops locks the mux parent adapter individually. Signed-off-by: Peter Rosin Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core.c | 1 + drivers/i2c/i2c-mux.c | 152 +++++++++++++++++++++++++++++++++--- drivers/i2c/muxes/i2c-mux-gpio.c | 18 +++++ drivers/i2c/muxes/i2c-mux-pinctrl.c | 38 +++++++++ include/linux/i2c-mux.h | 8 ++ include/linux/i2c.h | 1 + 6 files changed, 205 insertions(+), 13 deletions(-) (limited to 'drivers/i2c/i2c-mux.c') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index afdee66002db..9da446162529 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1540,6 +1540,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) } rt_mutex_init(&adap->bus_lock); + rt_mutex_init(&adap->mux_lock); mutex_init(&adap->userspace_clients_lock); INIT_LIST_HEAD(&adap->userspace_clients); 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) diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c index f6270ee934f9..e5cf26eefa97 100644 --- a/drivers/i2c/muxes/i2c-mux-gpio.c +++ b/drivers/i2c/muxes/i2c-mux-gpio.c @@ -15,6 +15,7 @@ #include #include #include +#include "../../gpio/gpiolib.h" #include struct gpiomux { @@ -137,6 +138,7 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev) struct i2c_mux_core *muxc; struct gpiomux *mux; struct i2c_adapter *parent; + struct i2c_adapter *root; unsigned initial_state, gpio_base; int i, ret; @@ -184,6 +186,9 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev) platform_set_drvdata(pdev, muxc); + root = i2c_root_adapter(&parent->dev); + + muxc->mux_locked = true; mux->gpio_base = gpio_base; if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) { @@ -194,6 +199,9 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev) } for (i = 0; i < mux->data.n_gpios; i++) { + struct device *gpio_dev; + struct gpio_desc *gpio_desc; + ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio"); if (ret) { dev_err(&pdev->dev, "Failed to request GPIO %d\n", @@ -210,8 +218,18 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev) i++; /* gpio_request above succeeded, so must free */ goto err_request_gpio; } + + if (!muxc->mux_locked) + continue; + + gpio_desc = gpio_to_desc(gpio_base + mux->data.gpios[i]); + gpio_dev = &gpio_desc->gdev->dev; + muxc->mux_locked = i2c_root_adapter(gpio_dev) == root; } + if (muxc->mux_locked) + dev_info(&pdev->dev, "mux-locked i2c mux\n"); + for (i = 0; i < mux->data.n_values; i++) { u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0; unsigned int class = mux->data.classes ? mux->data.classes[i] : 0; diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c index f4e62f4a50cc..35bb775e1b74 100644 --- a/drivers/i2c/muxes/i2c-mux-pinctrl.c +++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c @@ -24,6 +24,7 @@ #include #include #include +#include "../../pinctrl/core.h" struct i2c_mux_pinctrl { struct i2c_mux_pinctrl_platform_data *pdata; @@ -120,10 +121,31 @@ static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux, } #endif +static struct i2c_adapter *i2c_mux_pinctrl_root_adapter( + struct pinctrl_state *state) +{ + struct i2c_adapter *root = NULL; + struct pinctrl_setting *setting; + struct i2c_adapter *pin_root; + + list_for_each_entry(setting, &state->settings, node) { + pin_root = i2c_root_adapter(setting->pctldev->dev); + if (!pin_root) + return NULL; + if (!root) + root = pin_root; + else if (root != pin_root) + return NULL; + } + + return root; +} + static int i2c_mux_pinctrl_probe(struct platform_device *pdev) { struct i2c_mux_core *muxc; struct i2c_mux_pinctrl *mux; + struct i2c_adapter *root; int i, ret; mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL); @@ -202,6 +224,22 @@ static int i2c_mux_pinctrl_probe(struct platform_device *pdev) goto err; } + root = i2c_root_adapter(&muxc->parent->dev); + + muxc->mux_locked = true; + for (i = 0; i < mux->pdata->bus_count; i++) { + if (root != i2c_mux_pinctrl_root_adapter(mux->states[i])) { + muxc->mux_locked = false; + break; + } + } + if (muxc->mux_locked && mux->pdata->pinctrl_state_idle && + root != i2c_mux_pinctrl_root_adapter(mux->state_idle)) + muxc->mux_locked = false; + + if (muxc->mux_locked) + dev_info(&pdev->dev, "mux-locked i2c mux\n"); + for (i = 0; i < mux->pdata->bus_count; i++) { u32 bus = mux->pdata->base_bus_num ? (mux->pdata->base_bus_num + i) : 0; diff --git a/include/linux/i2c-mux.h b/include/linux/i2c-mux.h index 2fa93fe1345e..d4c1d12f900d 100644 --- a/include/linux/i2c-mux.h +++ b/include/linux/i2c-mux.h @@ -27,9 +27,12 @@ #ifdef __KERNEL__ +#include + struct i2c_mux_core { struct i2c_adapter *parent; struct device *dev; + bool mux_locked; void *priv; @@ -47,11 +50,16 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent, int (*select)(struct i2c_mux_core *, u32), int (*deselect)(struct i2c_mux_core *, u32)); +/* flags for i2c_mux_alloc */ +#define I2C_MUX_LOCKED BIT(0) + static inline void *i2c_mux_priv(struct i2c_mux_core *muxc) { return muxc->priv; } +struct i2c_adapter *i2c_root_adapter(struct device *dev); + /* * Called to create an i2c bus on a multiplexed bus segment. * The chan_id parameter is passed to the select and deselect diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 50934d6e1050..96a25ae14494 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -524,6 +524,7 @@ struct i2c_adapter { /* data fields that are valid for all devices */ struct rt_mutex bus_lock; + struct rt_mutex mux_lock; int timeout; /* in jiffies */ int retries; -- cgit v1.2.3