include/linux/input/adxl34x.h

Source file repositories/reference/linux-study-clean/include/linux/input/adxl34x.h

File Facts

System
Linux kernel
Corpus path
include/linux/input/adxl34x.h
Extension
.h
Size
11580 bytes
Lines
358
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct adxl34x_platform_data {

	/*
	 * X,Y,Z Axis Offset:
	 * offer user offset adjustments in twoscompliment
	 * form with a scale factor of 15.6 mg/LSB (i.e. 0x7F = +2 g)
	 */

	s8 x_axis_offset;
	s8 y_axis_offset;
	s8 z_axis_offset;

	/*
	 * TAP_X/Y/Z Enable: Setting TAP_X, Y, or Z Enable enables X,
	 * Y, or Z participation in Tap detection. A '0' excludes the
	 * selected axis from participation in Tap detection.
	 * Setting the SUPPRESS bit suppresses Double Tap detection if
	 * acceleration greater than tap_threshold is present during the
	 * tap_latency period, i.e. after the first tap but before the
	 * opening of the second tap window.
	 */

#define ADXL_SUPPRESS	(1 << 3)
#define ADXL_TAP_X_EN	(1 << 2)
#define ADXL_TAP_Y_EN	(1 << 1)
#define ADXL_TAP_Z_EN	(1 << 0)

	u8 tap_axis_control;

	/*
	 * tap_threshold:
	 * holds the threshold value for tap detection/interrupts.
	 * The data format is unsigned. The scale factor is 62.5 mg/LSB
	 * (i.e. 0xFF = +16 g). A zero value may result in undesirable
	 * behavior if Tap/Double Tap is enabled.
	 */

	u8 tap_threshold;

	/*
	 * tap_duration:
	 * is an unsigned time value representing the maximum
	 * time that an event must be above the tap_threshold threshold
	 * to qualify as a tap event. The scale factor is 625 us/LSB. A zero
	 * value will prevent Tap/Double Tap functions from working.
	 */

	u8 tap_duration;

	/*
	 * tap_latency:
	 * is an unsigned time value representing the wait time
	 * from the detection of a tap event to the opening of the time
	 * window tap_window for a possible second tap event. The scale
	 * factor is 1.25 ms/LSB. A zero value will disable the Double Tap
	 * function.
	 */

	u8 tap_latency;

	/*
	 * tap_window:
	 * is an unsigned time value representing the amount
	 * of time after the expiration of tap_latency during which a second
	 * tap can begin. The scale factor is 1.25 ms/LSB. A zero value will
	 * disable the Double Tap function.
	 */

	u8 tap_window;

	/*
	 * act_axis_control:
	 * X/Y/Z Enable: A '1' enables X, Y, or Z participation in activity
	 * or inactivity detection. A '0' excludes the selected axis from
	 * participation. If all of the axes are excluded, the function is
	 * disabled.
	 * AC/DC: A '0' = DC coupled operation and a '1' = AC coupled
	 * operation. In DC coupled operation, the current acceleration is
	 * compared with activity_threshold and inactivity_threshold directly
	 * to determine whether activity or inactivity is detected. In AC
	 * coupled operation for activity detection, the acceleration value
	 * at the start of activity detection is taken as a reference value.
	 * New samples of acceleration are then compared to this
	 * reference value and if the magnitude of the difference exceeds
	 * activity_threshold the device will trigger an activity interrupt. In
	 * AC coupled operation for inactivity detection, a reference value
	 * is used again for comparison and is updated whenever the
	 * device exceeds the inactivity threshold. Once the reference
	 * value is selected, the device compares the magnitude of the
	 * difference between the reference value and the current

Annotation

Implementation Notes