i2c-core.c

linux 内核源代码

		/* legacy drivers create and remove clients themselves */
		if ((res = driver->detach_client(client))) {
			dev_err(&adap->dev, "detach_client failed for client "
				"[%s] at address 0x%02x\n", client->name,
				client->addr);
			goto out_unlock;
		}
	}

	/* 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);

	/* free bus id */
	idr_remove(&i2c_adapter_idr, adap->nr);

	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);

 out_unlock:
	mutex_unlock(&core_lists);
	return res;
}
EXPORT_SYMBOL(i2c_del_adapter);


/* ------------------------------------------------------------------------- */

/*
 * An i2c_driver is used with one or more i2c_client (device) nodes to access
 * i2c slave chips, on a bus instance associated with some i2c_adapter.  There
 * are two models for binding the driver to its device:  "new style" drivers
 * follow the standard Linux driver model and just respond to probe() calls
 * issued if the driver core sees they match(); "legacy" drivers create device
 * nodes themselves.
 */

int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
{
	int res;

	/* new style driver methods can't mix with legacy ones */
	if (is_newstyle_driver(driver)) {
		if (driver->attach_adapter || driver->detach_adapter
				|| driver->detach_client) {
			printk(KERN_WARNING
					"i2c-core: driver [%s] is confused\n",
					driver->driver.name);
			return -EINVAL;
		}
	}

	/* add the driver to the list of i2c drivers in the driver core */
	driver->driver.owner = owner;
	driver->driver.bus = &i2c_bus_type;

	/* for new style drivers, when registration returns the driver core
	 * will have called probe() for all matching-but-unbound devices.
	 */
	res = driver_register(&driver->driver);
	if (res)
		return res;

	mutex_lock(&core_lists);

	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) {
			driver->attach_adapter(adapter);
		}
	}

	mutex_unlock(&core_lists);
	return 0;
}
EXPORT_SYMBOL(i2c_register_driver);

/**
 * i2c_del_driver - unregister I2C driver
 * @driver: the driver being unregistered
 * Context: can sleep
 */
void i2c_del_driver(struct i2c_driver *driver)
{
	struct list_head   *item1, *item2, *_n;
	struct i2c_client  *client;
	struct i2c_adapter *adap;

	mutex_lock(&core_lists);

	/* new-style driver? */
	if (is_newstyle_driver(driver))
		goto unregister;

	/* Have a look at each adapter, if clients of this driver are still
	 * 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);
		if (driver->detach_adapter) {
			if (driver->detach_adapter(adap)) {
				dev_err(&adap->dev, "detach_adapter failed "
					"for driver [%s]\n",
					driver->driver.name);
			}
		} else {
			list_for_each_safe(item2, _n, &adap->clients) {
				client = list_entry(item2, struct i2c_client, list);
				if (client->driver != driver)
					continue;
				dev_dbg(&adap->dev, "detaching client [%s] "
					"at 0x%02x\n", client->name,
					client->addr);
				if (driver->detach_client(client)) {
					dev_err(&adap->dev, "detach_client "
						"failed for client [%s] at "
						"0x%02x\n", client->name,
						client->addr);
				}
			}
		}
	}

 unregister:
	driver_unregister(&driver->driver);
	list_del(&driver->list);
	pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);

	mutex_unlock(&core_lists);
}
EXPORT_SYMBOL(i2c_del_driver);

/* ------------------------------------------------------------------------- */

static int __i2c_check_addr(struct i2c_adapter *adapter, unsigned int addr)
{
	struct list_head   *item;
	struct i2c_client  *client;

	list_for_each(item,&adapter->clients) {
		client = list_entry(item, struct i2c_client, list);
		if (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;
}

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;

	if (client->driver)
		client->dev.driver = &client->driver->driver;

	if (client->driver && !is_newstyle_driver(client->driver)) {
		client->dev.release = i2c_client_release;
		client->dev.uevent_suppress = 1;
	} else
		client->dev.release = i2c_client_dev_release;

	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;
	mutex_unlock(&adapter->clist_lock);

	if (adapter->client_register)  {
		if (adapter->client_register(client)) {
			dev_dbg(&adapter->dev, "client_register "
				"failed for client [%s] at 0x%02x\n",
				client->name, client->addr);
		}
	}

	return 0;

out_list:
	list_del(&client->list);
	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);

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) {
			dev_err(&client->dev,
				"client_unregister [%s] failed, "
				"client not detached\n", client->name);
			goto out;
		}
	}

	mutex_lock(&adapter->clist_lock);
	list_del(&client->list);
	init_completion(&client->released);
	device_unregister(&client->dev);
	mutex_unlock(&adapter->clist_lock);
	wait_for_completion(&client->released);

 out:
	return res;
}
EXPORT_SYMBOL(i2c_detach_client);

static int i2c_inc_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;
}

static void i2c_dec_use_client(struct i2c_client *client)
{
	module_put(client->driver->driver.owner);
	module_put(client->adapter->owner);
}

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);

int i2c_release_client(struct i2c_client *client)
{
	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);

	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;

	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);
}
EXPORT_SYMBOL(i2c_clients_command);

static int __init i2c_init(void)
{
	int retval;

	retval = bus_register(&i2c_bus_type);
	if (retval)
		return retval;
	return class_register(&i2c_adapter_class);
}

static void __exit i2c_exit(void)
{
	class_unregister(&i2c_adapter_class);
	bus_unregister(&i2c_bus_type);
}

subsys_initcall(i2c_init);
module_exit(i2c_exit);

/* ----------------------------------------------------
 * the functional interface to the i2c busses.
 * ----------------------------------------------------
 */

int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num)
{
	int ret;

	if (adap->algo->master_xfer) {
#ifdef DEBUG
		for (ret = 0; ret < num; ret++) {
			dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
				"len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
				? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
				(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
		}
#endif

		mutex_lock_nested(&adap->bus_lock, adap->level);
		ret = adap->algo->master_xfer(adap,msgs,num);
		mutex_unlock(&adap->bus_lock);

		return ret;
	} else {
		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
		return -ENOSYS;
	}
}
EXPORT_SYMBOL(i2c_transfer);

int i2c_master_send(struct i2c_client *client,const char *buf ,int count)
{
	int ret;
	struct i2c_adapter *adap=client->adapter;
	struct i2c_msg msg;

	msg.addr = client->addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.len = count;
	msg.buf = (char *)buf;

	ret = i2c_transfer(adap, &msg, 1);

	/* If everything went ok (i.e. 1 msg transmitted), return #bytes
	   transmitted, else error code. */
	return (ret == 1) ? count : ret;
}
EXPORT_SYMBOL(i2c_master_send);

int i2c_master_recv(struct i2c_client *client, char *buf ,int count)
{
	struct i2c_adapter *adap=client->adapter;
	struct i2c_msg msg;
	int ret;

	msg.addr = client->addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.flags |= I2C_M_RD;
	msg.len = count;
	msg.buf = buf;

	ret = i2c_transfer(adap, &msg, 1);

	/* If everything went ok (i.e. 1 msg transmitted), return #bytes
	   transmitted, else error code. */
	return (ret == 1) ? count : ret;
}
EXPORT_SYMBOL(i2c_master_recv);

/* ----------------------------------------------------
 * the i2c address scanning function
 * Will not work for 10-bit addresses!
 * ----------------------------------------------------
 */
static int i2c_probe_address(struct i2c_adapter *adapter, int addr, int kind,
			     int (*found_proc) (struct i2c_adapter *, int, int))
{
	int err;

	/* Make sure the address is valid */
	if (addr < 0x03 || addr > 0x77) {
		dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
			 addr);
		return -EINVAL;
	}

	/* Skip if already in use */
	if (i2c_check_addr(adapter, addr))
		return 0;

	/* Make sure there is something at this address, unless forced */
	if (kind < 0) {
		if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
				   I2C_SMBUS_QUICK, NULL) < 0)
			return 0;

		/* prevent 24RF08 corruption */
		if ((addr & ~0x0f) == 0x50)
			i2c_smbus_xfer(adapter, addr, 0, 0, 0,
				       I2C_SMBUS_QUICK, NULL);
	}

	/* Finally call the custom detection function */
	err = found_proc(adapter, addr, kind);
	/* -ENODEV can be returned if there is a chip at the given address
	   but it isn't supported by this chip driver. We catch it here as
	   this isn't an error. */
	if (err == -ENODEV)
		err = 0;

	if (err)
		dev_warn(&adapter->dev, "Client creation failed at 0x%x (%d)\n",
			 addr, err);
	return err;
}

int i2c_probe(struct i2c_adapter *adapter,
	      struct i2c_client_address_data *address_data,
	      int (*found_proc) (struct i2c_adapter *, int, int))
{
	int i, err;
	int adap_id = i2c_adapter_id(adapter);

	/* Force entries are done first, and are not affected by ignore
	   entries */
	if (address_data->forces) {
		unsigned short **forces = address_data->forces;
		int kind;

		for (kind = 0; forces[kind]; kind++) {
			for (i = 0; forces[kind][i] != I2C_CLIENT_END;
			     i += 2) {
				if (forces[kind][i] == adap_id
				 || forces[kind][i] == ANY_I2C_BUS) {
					dev_dbg(&adapter->dev, "found force "
						"parameter for adapter %d, "
						"addr 0x%02x, kind %d\n",
						adap_id, forces[kind][i + 1],
						kind);
					err = i2c_probe_address(adapter,
						forces[kind][i + 1],
						kind, found_proc);
					if (err)
						return err;
				}
			}
		}
	}

	/* Stop here if we can't use SMBUS_QUICK */
	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) {
		if (address_data->probe[0] == I2C_CLIENT_END
		 && address_data->normal_i2c[0] == I2C_CLIENT_END)
			return 0;

		dev_warn(&adapter->dev, "SMBus Quick command not supported, "
			 "can't probe for chips\n");
		return -1;
	}

	/* Probe entries are done second, and are not affected by ignore
	   entries either */
	for (i = 0; address_data->probe[i] != I2C_CLIENT_END; i += 2) {
		if (address_data->probe[i] == adap_id
		 || address_data->probe[i] == ANY_I2C_BUS) {
			dev_dbg(&adapter->dev, "found probe parameter for "
				"adapter %d, addr 0x%02x\n", adap_id,
				address_data->probe[i + 1]);
			err = i2c_probe_address(adapter,
						address_data->probe[i + 1],
						-1, found_proc);
			if (err)
				return err;
		}
	}