// Send sleep command to touchpad over HID u8 sleep_cmd[] = 0x00, 0x02; // Vendor-specific sleep opcode hid_hw_raw_request(hdev, 0x02, sleep_cmd, 2, HID_FEATURE_REPORT, HID_REQ_SET_REPORT); return 0;
input_mt_sync_frame(input); input_sync(input); return 0; The driver optionally performs basic gesture detection (two-finger scroll, pinch) before passing events up. hid compliant touchpad driver
struct input_dev *input; input = devm_input_allocate_device(&hdev->dev); input_set_abs_params(input, ABS_MT_POSITION_X, 0, 4095, 0, 0); input_set_abs_params(input, ABS_MT_POSITION_Y, 0, 4095, 0, 0); input_set_abs_params(input, ABS_MT_TRACKING_ID, 0, 255, 0, 0); // Send sleep command to touchpad over HID
For low-level drivers, gestures can be delegated to userspace (e.g., libinput). Touchpad drivers must support suspend/resume and idle power reduction. The Human Interface Device (HID) standard, defined by
—HID, Touchpad Driver, Multi-touch, Input Subsystem, USB, Linux Kernel, MT Protocol B. I. Introduction Modern laptops and input devices rely on touchpads for cursor control, tapping, and multi-finger gestures. The Human Interface Device (HID) standard, defined by the USB-IF, provides a unified protocol for input devices. However, implementing a custom touchpad driver that is HID-compliant requires careful handling of report descriptors, touch tracking, and OS-specific quirks.
static void detect_gesture(struct touch_data *touches, int count)
Abstract —Touchpads have become ubiquitous input devices for portable computing systems. However, operating system compatibility, gesture recognition, and power efficiency remain challenges for custom touchpad hardware. This paper presents the design and implementation of a HID-compliant touchpad driver that bridges custom touchpad hardware with standard operating system input subsystems. We detail the USB HID descriptor structure, multi-touch protocol (MT Protocol B), interrupt handling, gesture interpretation, and power management. The driver is implemented for a Linux kernel module and validated against Windows 11 and macOS evdev compatibility layers. Experimental results show sub-10ms latency, support for up to 5 simultaneous touches, and average power consumption of 8.5mW.