#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/completion.h>
+#include <linux/hardirq.h>
+#include <linux/irqflags.h>
#include <asm/uaccess.h>
+#include <asm/semaphore.h>
#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)
.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
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 */
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,
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;
}
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)
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
*/
status = -EBUSY;
idr_remove(&i2c_adapter_idr, id);
}
- mutex_unlock(&core_lists);
+ mutex_unlock(&core_lock);
if (status == -EAGAIN)
goto 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
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. */
/* 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);
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);
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);
*/
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))
* 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 "
}
}
}
+ 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;
}
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);
}
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;
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 "
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);
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) {
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:
}
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);
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);
}
}
#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);
}
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;
/* 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++) {
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) {
}
/* 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;
break;
}
}
- mutex_unlock(&adap->clist_lock);
if (addr_list[i] == I2C_CLIENT_END) {
dev_dbg(&adap->dev, "Probing failed, no device found\n");
{
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);
git.samba.org / sfrench / cifs-2.6.git / blobdiff