Input core input. c (1)

Drivers/input. c

Is the so-called input core program.

Analyze this file and start with input_init.

   1:  static int __init input_init(void)

   2:  {

   3:  err = class_register(&input_class);

   4:  err = input_proc_init();

   5:  err = register_chrdev(INPUT_MAJOR, "input", &input_fops);

   6:  }

_ Init put it in the init. text segment, which will be called during initialization. This is the case when the function removes the check. Class_register registers the class type in the device model. In _ class_register

1:/* initialize the private data of the class */

2:/* cp is a class_private type, private type of class */

   3:  cp = kzalloc(sizeof(*cp), GFP_KERNEL);

4:/* initialize the get/put function of klist. Actually, get_device and put_device are called */

   5:  klist_init(&cp->class_devices, klist_class_dev_get, klist_class_dev_put);

   6:  INIT_LIST_HEAD(&cp->class_interfaces);

   7:  kset_init(&cp->class_dirs);

   8:  __mutex_init(&cp->class_mutex, "struct class mutex", key);

   9:  error = kobject_set_name(&cp->class_subsys.kobj, "%s", cls->name);

  10:      

  11:  /* set the default /sys/dev directory for devices of this class */

  12:  if (!cls->dev_kobj)

  13:      cls->dev_kobj = sysfs_dev_char_kobj;

14:/* register the kset. initialize the kset first. Obtain the kobject here and create a directory */

  15:  error = kset_register(&cp->class_subsys);

16:/* Create an attribute file and traverse its attribute. If you are familiar with the device model, you will know that the attribute actually corresponds to the file */

  17:  error = add_class_attrs(class_get(cls));

  18:   

In input_init, the next input_proc_init function is used to create a directory, file, and register the corresponding fops In the proc file system.

This is simple:

1:/* set up the input directory under proc */

   2:  proc_bus_input_dir = proc_mkdir("bus/input", NULL);

3:/* create two devices and handlers files under bus/input, and register their fops. The two fops are in the input. defined in c, the fops function is also in input. c. */

   4:  entry = proc_create("devices", 0, proc_bus_input_dir,

   5:              &input_devices_fileops);

   6:  entry = proc_create("handlers", 0, proc_bus_input_dir,

   7:              &input_handlers_fileops);

   8:      

The following register_chardev registers a character device with the primary device number being INPUT_MAJOR, the secondary device number ranging from 0 to 256, and the file operator being input_fops.

After reading input_init, let's look at input. c. The second half is the fops function. The first part is some interface functions, and the middle part is

Handle and handler functions.

To be continued