四、注册 i2c_driver

前三步跟平台相关，从这里开始就只与具体的设备驱动相关了，这里我选取FLD00060 光距感的驱动进行说明。

 

// 3rdparty/lsensor/fld60/special/driver/FLD60.c

static int __init fld60_pls_init(void)

{

       int temp=0;

       printk("baker :%s\n",__func__);

       fld60_pls_config_pins();

       printk("after baker :%s\n",__func__);

       temp = i2c_add_driver(&fld60_pls_driver);

       printk("add driver result = %d--\n",temp);

       return temp;

}

 

//kernel/include/linux/i2c.h

static inline int i2c_add_driver(struct i2c_driver *driver)

{

       return i2c_register_driver(THIS_MODULE, driver);

}

 

 

/*

 * An i2c_driver is used with one or morei2c_client (device) nodes to access

 * i2c slave chips, on a bus instanceassociated with some i2c_adapter.

 */

//kernel/drivers/i2c/i2c-core.c

int i2c_register_driver(struct module *owner, struct i2c_driver*driver)

{

       int res;

 

       /* Can't register until after drivermodel init */

       if (unlikely(WARN_ON(!i2c_bus_type.p)))

              return -EAGAIN;

 

       /* add the driver to the list of i2cdrivers in the driver core */

       driver->driver.owner = owner;

       driver->driver.bus =&i2c_bus_type;

 

       /* Whenregistration returns, the driver core

        * will have called probe() for allmatching-but-unbound devices.

        */

      //i2c_driver结构体中的driver变量是个device_driver类型的结构体

       res = driver_register(&driver->driver);

 

       if (res)

              return res;

 

       pr_debug("i2c-core: driver [%s]registered\n", driver->driver.name);

 

       INIT_LIST_HEAD(&driver->clients);

       /* Walk the adapters that are alreadypresent */

       mutex_lock(&core_lock);

       bus_for_each_dev(&i2c_bus_type, NULL,driver, __process_new_driver);

       mutex_unlock(&core_lock);

 

       return 0;

}

 

 

/**

 * driver_register - register driver with bus

 * @drv: driver to register

 *

 * We pass off most of the work to thebus_add_driver() call,

 * since most of the things we have to do dealwith the bus

 * structures.

 */

//kernel/drivers/base/driver.c

int driver_register(struct device_driver *drv)

{

       int ret;

       struct device_driver *other;

 

       BUG_ON(!drv->bus->p);

 

       if ((drv->bus->probe &&drv->probe) ||

          (drv->bus->remove && drv->remove) ||

          (drv->bus->shutdown && drv->shutdown))

              printk(KERN_WARNING "Driver'%s' needs updating - please use "

                     "bus_typemethods\n", drv->name);

 

       other = driver_find(drv->name,drv->bus);

       if (other) {

              put_driver(other);

              printk(KERN_ERR "Error:Driver '%s' is already registered, "

                     "aborting...\n",drv->name);

              return -EBUSY;

       }

 

       ret = bus_add_driver(drv);

       if (ret)

              return ret;

       ret = driver_add_groups(drv,drv->groups);

       if (ret)

              bus_remove_driver(drv);

       return ret;

}

 

 

/**

 * bus_add_driver - Add a driver to the bus.