X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fi2c%2Fi2c-core.c;h=96da22e9a5a44dbe32b247694a2b72bdea20c0d8;hb=7cedb1f17fb7f4374d11501f61656ae9d3ba47e9;hp=e73d58c43f386a349856cdb95f2935510c2a79fe;hpb=347c53dca73fca317d57781f510f5ff4f6c0d0d7;p=linux-2.6-omap-h63xx.git diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index e73d58c43f3..96da22e9a5a 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -17,7 +17,7 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* ------------------------------------------------------------------------- */ -/* With some changes from Kyösti Mälkki . +/* With some changes from Kyösti Mälkki . All SMBus-related things are written by Frodo Looijaard SMBus 2.0 support by Mark Studebaker and Jean Delvare */ @@ -33,14 +33,15 @@ #include #include #include +#include +#include #include +#include #include "i2c-core.h" -static LIST_HEAD(adapters); -static LIST_HEAD(drivers); -static DEFINE_MUTEX(core_lists); +static DEFINE_MUTEX(core_lock); static DEFINE_IDR(i2c_adapter_idr); #define is_newstyle_driver(d) ((d)->probe || (d)->remove) @@ -198,6 +199,25 @@ static struct bus_type i2c_bus_type = { .resume = i2c_device_resume, }; + +/** + * i2c_verify_client - return parameter as i2c_client, or NULL + * @dev: device, probably from some driver model iterator + * + * When traversing the driver model tree, perhaps using driver model + * iterators like @device_for_each_child(), you can't assume very much + * about the nodes you find. Use this function to avoid oopses caused + * by wrongly treating some non-I2C device as an i2c_client. + */ +struct i2c_client *i2c_verify_client(struct device *dev) +{ + return (dev->bus == &i2c_bus_type) + ? to_i2c_client(dev) + : NULL; +} +EXPORT_SYMBOL(i2c_verify_client); + + /** * i2c_new_device - instantiate an i2c device for use with a new style driver * @adap: the adapter managing the device @@ -276,6 +296,50 @@ void i2c_unregister_device(struct i2c_client *client) EXPORT_SYMBOL_GPL(i2c_unregister_device); +static int dummy_nop(struct i2c_client *client) +{ + return 0; +} + +static struct i2c_driver dummy_driver = { + .driver.name = "dummy", + .probe = dummy_nop, + .remove = dummy_nop, +}; + +/** + * i2c_new_dummy - return a new i2c device bound to a dummy driver + * @adapter: the adapter managing the device + * @address: seven bit address to be used + * @type: optional label used for i2c_client.name + * Context: can sleep + * + * This returns an I2C client bound to the "dummy" driver, intended for use + * with devices that consume multiple addresses. Examples of such chips + * include various EEPROMS (like 24c04 and 24c08 models). + * + * These dummy devices have two main uses. First, most I2C and SMBus calls + * except i2c_transfer() need a client handle; the dummy will be that handle. + * And second, this prevents the specified address from being bound to a + * different driver. + * + * This returns the new i2c client, which should be saved for later use with + * i2c_unregister_device(); or NULL to indicate an error. + */ +struct i2c_client * +i2c_new_dummy(struct i2c_adapter *adapter, u16 address, const char *type) +{ + struct i2c_board_info info = { + .driver_name = "dummy", + .addr = address, + }; + + if (type) + strlcpy(info.type, type, sizeof info.type); + return i2c_new_device(adapter, &info); +} +EXPORT_SYMBOL_GPL(i2c_new_dummy); + /* ------------------------------------------------------------------------- */ /* I2C bus adapters -- one roots each I2C or SMBUS segment */ @@ -320,18 +384,27 @@ static void i2c_scan_static_board_info(struct i2c_adapter *adapter) mutex_unlock(&__i2c_board_lock); } +static int i2c_do_add_adapter(struct device_driver *d, void *data) +{ + struct i2c_driver *driver = to_i2c_driver(d); + struct i2c_adapter *adap = data; + + if (driver->attach_adapter) { + /* We ignore the return code; if it fails, too bad */ + driver->attach_adapter(adap); + } + return 0; +} + static int i2c_register_adapter(struct i2c_adapter *adap) { - int res = 0; - struct list_head *item; - struct i2c_driver *driver; + int res = 0, dummy; mutex_init(&adap->bus_lock); mutex_init(&adap->clist_lock); INIT_LIST_HEAD(&adap->clients); - mutex_lock(&core_lists); - list_add_tail(&adap->list, &adapters); + mutex_lock(&core_lock); /* Add the adapter to the driver core. * If the parent pointer is not set up, @@ -356,19 +429,14 @@ static int i2c_register_adapter(struct i2c_adapter *adap) i2c_scan_static_board_info(adap); /* let legacy drivers scan this bus for matching devices */ - list_for_each(item,&drivers) { - driver = list_entry(item, struct i2c_driver, list); - if (driver->attach_adapter) - /* We ignore the return code; if it fails, too bad */ - driver->attach_adapter(adap); - } + dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap, + i2c_do_add_adapter); out_unlock: - mutex_unlock(&core_lists); + mutex_unlock(&core_lock); return res; out_list: - list_del(&adap->list); idr_remove(&i2c_adapter_idr, adap->nr); goto out_unlock; } @@ -394,11 +462,11 @@ retry: if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) return -ENOMEM; - mutex_lock(&core_lists); + mutex_lock(&core_lock); /* "above" here means "above or equal to", sigh */ res = idr_get_new_above(&i2c_adapter_idr, adapter, __i2c_first_dynamic_bus_num, &id); - mutex_unlock(&core_lists); + mutex_unlock(&core_lock); if (res < 0) { if (res == -EAGAIN) @@ -443,7 +511,7 @@ retry: if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) return -ENOMEM; - mutex_lock(&core_lists); + mutex_lock(&core_lock); /* "above" here means "above or equal to", sigh; * we need the "equal to" result to force the result */ @@ -452,7 +520,7 @@ retry: status = -EBUSY; idr_remove(&i2c_adapter_idr, id); } - mutex_unlock(&core_lists); + mutex_unlock(&core_lock); if (status == -EAGAIN) goto retry; @@ -462,6 +530,21 @@ retry: } EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); +static int i2c_do_del_adapter(struct device_driver *d, void *data) +{ + struct i2c_driver *driver = to_i2c_driver(d); + struct i2c_adapter *adapter = data; + int res; + + if (!driver->detach_adapter) + return 0; + res = driver->detach_adapter(adapter); + if (res) + dev_err(&adapter->dev, "detach_adapter failed (%d) " + "for driver [%s]\n", res, driver->driver.name); + return res; +} + /** * i2c_del_adapter - unregister I2C adapter * @adap: the adapter being unregistered @@ -473,35 +556,24 @@ EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); int i2c_del_adapter(struct i2c_adapter *adap) { struct list_head *item, *_n; - struct i2c_adapter *adap_from_list; - struct i2c_driver *driver; struct i2c_client *client; int res = 0; - mutex_lock(&core_lists); + mutex_lock(&core_lock); /* First make sure that this adapter was ever added */ - list_for_each_entry(adap_from_list, &adapters, list) { - if (adap_from_list == adap) - break; - } - if (adap_from_list != adap) { + if (idr_find(&i2c_adapter_idr, adap->nr) != adap) { pr_debug("i2c-core: attempting to delete unregistered " "adapter [%s]\n", adap->name); res = -EINVAL; goto out_unlock; } - list_for_each(item,&drivers) { - driver = list_entry(item, struct i2c_driver, list); - if (driver->detach_adapter) - if ((res = driver->detach_adapter(adap))) { - dev_err(&adap->dev, "detach_adapter failed " - "for driver [%s]\n", - driver->driver.name); - goto out_unlock; - } - } + /* Tell drivers about this removal */ + res = bus_for_each_drv(&i2c_bus_type, NULL, adap, + i2c_do_del_adapter); + if (res) + goto out_unlock; /* detach any active clients. This must be done first, because * it can fail; in which case we give up. */ @@ -529,7 +601,6 @@ int i2c_del_adapter(struct i2c_adapter *adap) /* clean up the sysfs representation */ init_completion(&adap->dev_released); device_unregister(&adap->dev); - list_del(&adap->list); /* wait for sysfs to drop all references */ wait_for_completion(&adap->dev_released); @@ -540,7 +611,7 @@ int i2c_del_adapter(struct i2c_adapter *adap) dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); out_unlock: - mutex_unlock(&core_lists); + mutex_unlock(&core_lock); return res; } EXPORT_SYMBOL(i2c_del_adapter); @@ -583,21 +654,23 @@ int i2c_register_driver(struct module *owner, struct i2c_driver *driver) if (res) return res; - mutex_lock(&core_lists); + mutex_lock(&core_lock); - list_add_tail(&driver->list,&drivers); pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name); /* legacy drivers scan i2c busses directly */ if (driver->attach_adapter) { struct i2c_adapter *adapter; - list_for_each_entry(adapter, &adapters, list) { + down(&i2c_adapter_class.sem); + list_for_each_entry(adapter, &i2c_adapter_class.devices, + dev.node) { driver->attach_adapter(adapter); } + up(&i2c_adapter_class.sem); } - mutex_unlock(&core_lists); + mutex_unlock(&core_lock); return 0; } EXPORT_SYMBOL(i2c_register_driver); @@ -609,11 +682,11 @@ EXPORT_SYMBOL(i2c_register_driver); */ void i2c_del_driver(struct i2c_driver *driver) { - struct list_head *item1, *item2, *_n; + struct list_head *item2, *_n; struct i2c_client *client; struct i2c_adapter *adap; - mutex_lock(&core_lists); + mutex_lock(&core_lock); /* new-style driver? */ if (is_newstyle_driver(driver)) @@ -623,8 +696,8 @@ void i2c_del_driver(struct i2c_driver *driver) * attached. If so, detach them to be able to kill the driver * afterwards. */ - list_for_each(item1,&adapters) { - adap = list_entry(item1, struct i2c_adapter, list); + down(&i2c_adapter_class.sem); + list_for_each_entry(adap, &i2c_adapter_class.devices, dev.node) { if (driver->detach_adapter) { if (driver->detach_adapter(adap)) { dev_err(&adap->dev, "detach_adapter failed " @@ -648,57 +721,38 @@ void i2c_del_driver(struct i2c_driver *driver) } } } + up(&i2c_adapter_class.sem); unregister: driver_unregister(&driver->driver); - list_del(&driver->list); pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name); - mutex_unlock(&core_lists); + mutex_unlock(&core_lock); } EXPORT_SYMBOL(i2c_del_driver); /* ------------------------------------------------------------------------- */ -static int __i2c_check_addr(struct i2c_adapter *adapter, unsigned int addr) +static int __i2c_check_addr(struct device *dev, void *addrp) { - struct list_head *item; - struct i2c_client *client; + struct i2c_client *client = i2c_verify_client(dev); + int addr = *(int *)addrp; - list_for_each(item,&adapter->clients) { - client = list_entry(item, struct i2c_client, list); - if (client->addr == addr) - return -EBUSY; - } + if (client && client->addr == addr) + return -EBUSY; return 0; } -int i2c_check_addr(struct i2c_adapter *adapter, int addr) +static int i2c_check_addr(struct i2c_adapter *adapter, int addr) { - int rval; - - mutex_lock(&adapter->clist_lock); - rval = __i2c_check_addr(adapter, addr); - mutex_unlock(&adapter->clist_lock); - - return rval; + return device_for_each_child(&adapter->dev, &addr, __i2c_check_addr); } -EXPORT_SYMBOL(i2c_check_addr); int i2c_attach_client(struct i2c_client *client) { struct i2c_adapter *adapter = client->adapter; int res = 0; - mutex_lock(&adapter->clist_lock); - if (__i2c_check_addr(client->adapter, client->addr)) { - res = -EBUSY; - goto out_unlock; - } - list_add_tail(&client->list,&adapter->clients); - - client->usage_count = 0; - client->dev.parent = &client->adapter->dev; client->dev.bus = &i2c_bus_type; @@ -713,13 +767,17 @@ int i2c_attach_client(struct i2c_client *client) snprintf(&client->dev.bus_id[0], sizeof(client->dev.bus_id), "%d-%04x", i2c_adapter_id(adapter), client->addr); - dev_dbg(&adapter->dev, "client [%s] registered with bus id %s\n", - client->name, client->dev.bus_id); res = device_register(&client->dev); if (res) - goto out_list; + goto out_err; + + mutex_lock(&adapter->clist_lock); + list_add_tail(&client->list, &adapter->clients); mutex_unlock(&adapter->clist_lock); + dev_dbg(&adapter->dev, "client [%s] registered with bus id %s\n", + client->name, client->dev.bus_id); + if (adapter->client_register) { if (adapter->client_register(client)) { dev_dbg(&adapter->dev, "client_register " @@ -730,12 +788,9 @@ int i2c_attach_client(struct i2c_client *client) return 0; -out_list: - list_del(&client->list); +out_err: dev_err(&adapter->dev, "Failed to attach i2c client %s at 0x%02x " "(%d)\n", client->name, client->addr, res); -out_unlock: - mutex_unlock(&adapter->clist_lock); return res; } EXPORT_SYMBOL(i2c_attach_client); @@ -745,12 +800,6 @@ int i2c_detach_client(struct i2c_client *client) struct i2c_adapter *adapter = client->adapter; int res = 0; - if (client->usage_count > 0) { - dev_warn(&client->dev, "Client [%s] still busy, " - "can't detach\n", client->name); - return -EBUSY; - } - if (adapter->client_unregister) { res = adapter->client_unregister(client); if (res) { @@ -763,9 +812,10 @@ int i2c_detach_client(struct i2c_client *client) mutex_lock(&adapter->clist_lock); list_del(&client->list); + mutex_unlock(&adapter->clist_lock); + init_completion(&client->released); device_unregister(&client->dev); - mutex_unlock(&adapter->clist_lock); wait_for_completion(&client->released); out: @@ -773,72 +823,58 @@ int i2c_detach_client(struct i2c_client *client) } EXPORT_SYMBOL(i2c_detach_client); -static int i2c_inc_use_client(struct i2c_client *client) +/** + * i2c_use_client - increments the reference count of the i2c client structure + * @client: the client being referenced + * + * Each live reference to a client should be refcounted. The driver model does + * that automatically as part of driver binding, so that most drivers don't + * need to do this explicitly: they hold a reference until they're unbound + * from the device. + * + * A pointer to the client with the incremented reference counter is returned. + */ +struct i2c_client *i2c_use_client(struct i2c_client *client) { - - if (!try_module_get(client->driver->driver.owner)) - return -ENODEV; - if (!try_module_get(client->adapter->owner)) { - module_put(client->driver->driver.owner); - return -ENODEV; - } - - return 0; + get_device(&client->dev); + return client; } +EXPORT_SYMBOL(i2c_use_client); -static void i2c_dec_use_client(struct i2c_client *client) +/** + * i2c_release_client - release a use of the i2c client structure + * @client: the client being no longer referenced + * + * Must be called when a user of a client is finished with it. + */ +void i2c_release_client(struct i2c_client *client) { - module_put(client->driver->driver.owner); - module_put(client->adapter->owner); + put_device(&client->dev); } +EXPORT_SYMBOL(i2c_release_client); -int i2c_use_client(struct i2c_client *client) -{ - int ret; - - ret = i2c_inc_use_client(client); - if (ret) - return ret; - - client->usage_count++; - - return 0; -} -EXPORT_SYMBOL(i2c_use_client); +struct i2c_cmd_arg { + unsigned cmd; + void *arg; +}; -int i2c_release_client(struct i2c_client *client) +static int i2c_cmd(struct device *dev, void *_arg) { - if (!client->usage_count) { - pr_debug("i2c-core: %s used one too many times\n", - __FUNCTION__); - return -EPERM; - } - - client->usage_count--; - i2c_dec_use_client(client); + struct i2c_client *client = i2c_verify_client(dev); + struct i2c_cmd_arg *arg = _arg; + if (client && client->driver && client->driver->command) + client->driver->command(client, arg->cmd, arg->arg); return 0; } -EXPORT_SYMBOL(i2c_release_client); void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) { - struct list_head *item; - struct i2c_client *client; + struct i2c_cmd_arg cmd_arg; - mutex_lock(&adap->clist_lock); - list_for_each(item,&adap->clients) { - client = list_entry(item, struct i2c_client, list); - if (!try_module_get(client->driver->driver.owner)) - continue; - if (NULL != client->driver->command) { - mutex_unlock(&adap->clist_lock); - client->driver->command(client,cmd,arg); - mutex_lock(&adap->clist_lock); - } - module_put(client->driver->driver.owner); - } - mutex_unlock(&adap->clist_lock); + cmd_arg.cmd = cmd; + cmd_arg.arg = arg; + device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd); } EXPORT_SYMBOL(i2c_clients_command); @@ -849,11 +885,24 @@ static int __init i2c_init(void) retval = bus_register(&i2c_bus_type); if (retval) return retval; - return class_register(&i2c_adapter_class); + retval = class_register(&i2c_adapter_class); + if (retval) + goto bus_err; + retval = i2c_add_driver(&dummy_driver); + if (retval) + goto class_err; + return 0; + +class_err: + class_unregister(&i2c_adapter_class); +bus_err: + bus_unregister(&i2c_bus_type); + return retval; } static void __exit i2c_exit(void) { + i2c_del_driver(&dummy_driver); class_unregister(&i2c_adapter_class); bus_unregister(&i2c_bus_type); } @@ -880,7 +929,15 @@ int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num) } #endif - mutex_lock_nested(&adap->bus_lock, adap->level); + if (in_atomic() || irqs_disabled()) { + ret = mutex_trylock(&adap->bus_lock); + if (!ret) + /* I2C activity is ongoing. */ + return -EAGAIN; + } else { + mutex_lock_nested(&adap->bus_lock, adap->level); + } + ret = adap->algo->master_xfer(adap,msgs,num); mutex_unlock(&adap->bus_lock); @@ -979,7 +1036,7 @@ static int i2c_probe_address(struct i2c_adapter *adapter, int addr, int kind, } int i2c_probe(struct i2c_adapter *adapter, - struct i2c_client_address_data *address_data, + const struct i2c_client_address_data *address_data, int (*found_proc) (struct i2c_adapter *, int, int)) { int i, err; @@ -988,7 +1045,7 @@ int i2c_probe(struct i2c_adapter *adapter, /* Force entries are done first, and are not affected by ignore entries */ if (address_data->forces) { - unsigned short **forces = address_data->forces; + const unsigned short * const *forces = address_data->forces; int kind; for (kind = 0; forces[kind]; kind++) { @@ -1086,7 +1143,6 @@ i2c_new_probed_device(struct i2c_adapter *adap, return NULL; } - mutex_lock(&adap->clist_lock); for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { /* Check address validity */ if (addr_list[i] < 0x03 || addr_list[i] > 0x77) { @@ -1096,7 +1152,7 @@ i2c_new_probed_device(struct i2c_adapter *adap, } /* Check address availability */ - if (__i2c_check_addr(adap, addr_list[i])) { + if (i2c_check_addr(adap, addr_list[i])) { dev_dbg(&adap->dev, "Address 0x%02x already in " "use, not probing\n", addr_list[i]); continue; @@ -1124,7 +1180,6 @@ i2c_new_probed_device(struct i2c_adapter *adap, break; } } - mutex_unlock(&adap->clist_lock); if (addr_list[i] == I2C_CLIENT_END) { dev_dbg(&adap->dev, "Probing failed, no device found\n"); @@ -1140,12 +1195,12 @@ struct i2c_adapter* i2c_get_adapter(int id) { struct i2c_adapter *adapter; - mutex_lock(&core_lists); + mutex_lock(&core_lock); adapter = (struct i2c_adapter *)idr_find(&i2c_adapter_idr, id); if (adapter && !try_module_get(adapter->owner)) adapter = NULL; - mutex_unlock(&core_lists); + mutex_unlock(&core_lock); return adapter; } EXPORT_SYMBOL(i2c_get_adapter);