Hid Compliant Touchpad Driver May 2026

struct input_dev *input = hdev->input; int contact_count = data[0]; // First byte: number of touches int offset = 1; int i, slot, id; for (i = 0; i < contact_count && offset + 5 < size; i++) (data[offset + 5] << 8)); slot = input_mt_get_slot_by_key(input, tracking_id); if (slot < 0) continue; input_mt_slot(input, slot); input_mt_report_slot_state(input, MT_TOOL_FINGER, tip_switch); if (tip_switch) input_report_abs(input, ABS_MT_TRACKING_ID, tracking_id); input_report_abs(input, ABS_MT_POSITION_X, x); input_report_abs(input, ABS_MT_POSITION_Y, y); offset += 6;

static int tp_probe(struct hid_device *hdev, const struct hid_device_id *id) 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); We detail the USB HID descriptor structure, multi-touch

Average power measured: 8.5mW active, 0.8mW sleep. We tested the driver on three platforms: multi-touch protocol (MT Protocol B)

For low-level drivers, gestures can be delegated to userspace (e.g., libinput). Touchpad drivers must support suspend/resume and idle power reduction.

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.