diff options
| -rw-r--r-- | drivers/i2c/i2c-core.c | 1 | ||||
| -rw-r--r-- | drivers/i2c/i2c-mux.c | 152 | ||||
| -rw-r--r-- | drivers/i2c/muxes/i2c-mux-gpio.c | 18 | ||||
| -rw-r--r-- | drivers/i2c/muxes/i2c-mux-pinctrl.c | 38 | ||||
| -rw-r--r-- | include/linux/i2c-mux.h | 8 | ||||
| -rw-r--r-- | include/linux/i2c.h | 1 |
6 files changed, 205 insertions, 13 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index afdee66..9da4461 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 5fa8af7..8eee986 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 f6270ee..e5cf26e 100644 --- a/drivers/i2c/muxes/i2c-mux-gpio.c +++ b/drivers/i2c/muxes/i2c-mux-gpio.c @@ -15,6 +15,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/gpio.h> +#include "../../gpio/gpiolib.h" #include <linux/of_gpio.h> 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 f4e62f4..35bb775 100644 --- a/drivers/i2c/muxes/i2c-mux-pinctrl.c +++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c @@ -24,6 +24,7 @@ #include <linux/platform_device.h> #include <linux/slab.h> #include <linux/of.h> +#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 2fa93fe..d4c1d12 100644 --- a/include/linux/i2c-mux.h +++ b/include/linux/i2c-mux.h @@ -27,9 +27,12 @@ #ifdef __KERNEL__ +#include <linux/bitops.h> + 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 50934d6..96a25ae 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; |