Generating and reporting an input event

Device allocation and registration are essential, but they are not the main goals of an input device driver, which is designed to report events to the input core. Depending on the type of event your device supports, the kernel provides the appropriate APIs to report them to the core.

Given an EV_XXX capable device, the corresponding report function would be input_report_xxx(). The following table shows mappings between the most important event types and their report functions:

Event type	Report function	Code example
EV_KEY	input_report_key()	input_report_key(poll_dev->input, BTN_0, gpiod_get_value(ms-> reset_btn_desc) & 1);
EV_REL	input_report_rel()	input_report_rel(nunchuk->input, REL_X, (nunchuk->report.joy_x - 128)/10);
EV_ABS	input_report_abs()	input_report_abs(bma150->input, ABS_X, x_value); input_report_abs(bma150->input, ABS_Y, y_value); input_report_abs(bma150->input, ABS_Z, z_value);

 

Their respective prototypes are as follows:

void...