Linux I2C Drive----I2C-driven registration process (I2c_register_driver->driver_register (&driver->driver)->driver_find) __ Linux

Linux under the I2C-driven loading process, divided into I2C equipment layer, I2C adapter layer and I2C core layer

The I2C device driver layer is the drive we write for a particular I2C device, and the following is the I2C-driven registration process I understand.

In the I2C device driver we write, we call I2c_add_driver () to start I2C device-driven registration, which calls

I2c_register_driver Complete all Registration actions

static inline int i2c_add_driver (struct i2c_driver *driver)

{

Return I2c_register_driver (This_module, driver);

}

I2c_register_driver calls Driver_register () to add device drivers to the device-driven list of the bus:

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

{

int res;

* Can ' t register until after driver Model Init * *

if (Unlikely (warn_on (!I2C_BUS_TYPE.P))

Return-eagain;

Driver->driver.owner = owner;

Driver->driver.bus = &i2c_bus_type;

* When registration returns, the driver core

* would have called probe () for all matching-but-unbound devices.

*/

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 already present * *

Mutex_lock (&core_lock);

Bus_for_each_dev (&i2c_bus_type, NULL, Driver, __attach_adapter);

Mutex_unlock (&core_lock);

return 0;

}

In Driver_register, the driver_find is used to determine if the driver is registered and then calls

Bus_add_drive

To add device drivers to the bus

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_type methods\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;

}

Initializes the Priv->klist_devices value in Bus_add_driver and assigns the Priv to Drv->p

**************************************************************************

1, in arch/arm/mach-xxx/own platform file to add I2C information, beauty its name Yue: i2c_board_info

For example:

static struct I2c_board_info __initdata xxxi2c_board_info[] = {
{
I2c_board_info ("Abcd1", 0x20),/* string to match the back, 0x20 from the device address * *
. Platform_data = 0,
},
{
I2c_board_info ("Abcd2", 0x21),
. Platform_data = 0,
},
};

Then call I2c_register_board_info (1, Xxxi2c_board_info, Array_size (Xxxi2c_board_info));

The first argument is 0 or 1, and I don't know:-(.

2, in another device driver file, such as you put into the/driver/char under the character device, generally module_init (Func_init ()) Form, then call I2c_add_driver () can, there are several to define:

static const struct I2C_DEVICE_ID xxx_led_id[] = {
{"ABCD1", 0},/* The name must match the Board_info to invoke the probe function * *
{"Abcd2", 0},
{ }
};
Module_device_table (I2C, xxx_led_id);

static struct I2c_driver Xxx_led_driver = {
. Driver = {
. Name = "Yourname", * * This name does not need to be matched with another * *
. Owner = This_module,
},
. Probe = Xxx_led_probe,
. remove = Xxx_remove,
. id_table = xxx_led_id,
};

See, struct i2c_device_id inside the string and i2c_board_info inside the match, Xxx_led_probe will not call.

If you don't want to use the same probe, write a struct i2c_device_id and struct i2c_driver