From a16d6ebca6efb73f6402f36e5aebf84f61721856 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Sun, 3 Apr 2016 20:44:45 +0200 Subject: i2c: introduce helper function to get 8 bit address from a message Drivers do this in various ways, let's use one standard way of doing it. Note: I2C_M_RD is bit 0, so the code could be simplified. To be extremly robust and to advertise good coding practices, I still use the ternary operator and let the compilers do the optimizing job. Reviewed-by: Andy Shevchenko Signed-off-by: Wolfram Sang --- include/linux/i2c.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/i2c.h') diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 200cf13b00f6..c30833b7b073 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -654,6 +654,11 @@ static inline int i2c_adapter_id(struct i2c_adapter *adap) return adap->nr; } +static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg) +{ + return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0); +} + /** * module_i2c_driver() - Helper macro for registering a modular I2C driver * @__i2c_driver: i2c_driver struct -- cgit From 8320f495cf441d593f7cd4f30e6b63455be71a2c Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Wed, 4 May 2016 22:15:27 +0200 Subject: i2c: allow adapter drivers to override the adapter locking Add i2c_lock_bus() and i2c_unlock_bus(), which call the new lock_bus and unlock_bus ops in the adapter. These funcs/ops take an additional flags argument that indicates for what purpose the adapter is locked. There are two flags, I2C_LOCK_ROOT_ADAPTER and I2C_LOCK_SEGMENT, but they are both implemented the same. For now. Locking the root adapter means that the whole bus is locked, locking the segment means that only the current bus segment is locked (i.e. i2c traffic on the parent side of a mux is still allowed even if the child side of the mux is locked). Also support a trylock_bus op (but no function to call it, as it is not expected to be needed outside of the i2c core). Implement i2c_lock_adapter/i2c_unlock_adapter in terms of the new locking scheme (i.e. lock with the I2C_LOCK_ROOT_ADAPTER flag). Locking the root adapter and locking the segment is the same thing for all root adapters (e.g. in the normal case of a simple topology with no i2c muxes). The two locking variants are also the same for traditional muxes (aka parent-locked muxes). These muxes traverse the tree, locking each level as they go until they reach the root. This patch is preparatory for a later patch in the series introducing mux-locked muxes, which behave differently depending on the requested locking. Since all current users are using i2c_lock_adapter, which is a wrapper for I2C_LOCK_ROOT_ADAPTER, we only need to annotate the calls that will not need to lock the root adapter for mux-locked muxes. I.e. the instances that needs to use I2C_LOCK_SEGMENT instead of i2c_lock_adapter/I2C_LOCK_ROOT_ADAPTER. Those instances are in the i2c_transfer and i2c_smbus_xfer functions, so that mux-locked muxes can single out normal i2c accesses to its slave side and adjust the locking for those accesses. Signed-off-by: Peter Rosin Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core.c | 41 +++++++++++++++++++++++++++-------------- include/linux/i2c.h | 44 ++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 69 insertions(+), 16 deletions(-) (limited to 'include/linux/i2c.h') 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 */ -- cgit 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 'include/linux/i2c.h') 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