内核源代码 Documentation/i2c/upgrading-clients:
new style:
static struct i2c_driver example_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "example",
},
.id_table = example_idtable,
.probe = example_probe,
.remove = __devexit_p(example_remove),
.suspend = example_suspend,
.resume = example_resume,
};
old style:
static struct i2c_driver example_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "example",
},
.attach_adapter = example_attach_adapter,
.detach_client = __devexit_p(example_detach),
.suspend = example_suspend,
.resume = example_resume,
};
3.1.8 kernel code:
struct i2c_driver {
unsigned int class;
/* Notifies the driver that a new bus has appeared or is about to be
* removed. You should avoid using this if you can, it will probably
* be removed in a near future.
*/
int (*attach_adapter)(struct i2c_adapter *);
int (*detach_adapter)(struct i2c_adapter *);
/* Standard driver model interfaces */ 标准驱动模型 接口
int (*probe)(struct i2c_client *, const struct i2c_device_id *);
int (*remove)(struct i2c_client *);
。。。
int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
struct device_driver driver;
const struct i2c_device_id *id_table;
/* Device detection callback for automatic device creation */
int (*detect)(struct i2c_client *, struct i2c_board_info *);
const unsigned short *address_list;
struct list_head clients;
};
旧方式: 分析:
Match对应的操作函数为i2c_device_match()()。代码如下
static int i2c_device_match(struct device *dev, struct device_driver *drv)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_driver *driver = to_i2c_driver(drv);
/* make legacy i2c drivers bypass driver model probing entirely;
* such drivers scan each i2c adapter/bus themselves.
*/
if (!is_newstyle_driver(driver))
return 0;
/* match on an id table if there is one */
if (driver->id_table)
return i2c_match_id(driver->id_table, client) != NULL;
return 0;
}
如果该驱动不是一个new-style形式的。或者driver没有定义匹配的id_table.都会匹配失败。
继续跟踪进i2c_match_id():
static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
const struct i2c_client *client)
{
while (id->name[0]) {
if (strcmp(client->name, id->name) == 0)
return id;
id++;
}
return NULL;
}
由此可见。如果client的名字和driver->id_table[]中的名称匹配即为成功。
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