Kmdf Hid Minidriver For Touch I2c Device Calibration ✰

Assume your raw touch data from I2C is 3 bytes per coordinate (X/Y pressure). You read a packet:

typedef struct _RAW_TOUCH_REPORT 
    UCHAR TouchID;
    USHORT RawX;
    USHORT RawY;
    UCHAR Pressure;
 RAW_TOUCH_REPORT;

Calibration parameters could be stored in the registry, e.g.:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TouchCalibMini\Parameters]
"CalibMatrix"=hex:01,00,00,00,...

A simple linear calibration:

VOID ApplyCalibration(RAW_TOUCH_REPORT *raw, HID_TOUCH_REPORT *calib, PCALIB_PARAMS params)
calib->X = (raw->RawX - params->XMin) * params->ScreenWidth / (params->XMax - params->XMin);
    calib->Y = (raw->RawY - params->YMin) * params->ScreenHeight / (params->YMax - params->YMin);
    // Clip to screen bounds
    if (calib->X > params->ScreenWidth) calib->X = params->ScreenWidth;
    if (calib->Y > params->ScreenHeight) calib->Y = params->ScreenHeight;

Advanced calibration uses an affine matrix for rotation, skew, and translation:

X_cal = A * X_raw + B * Y_raw + C
Y_cal = D * X_raw + E * Y_raw + F

This corrects for misaligned sensor grids. kmdf hid minidriver for touch i2c device calibration

Key KMDF objects and components

HID specifics

Expose a private IOCTL that user‑mode calibration tool calls:

#define IOCTL_SET_CALIBRATION CTL_CODE(FILE_DEVICE_UNKNOWN, 0x800, METHOD_BUFFERED, FILE_ANY_ACCESS)
EVT_WDF_IO_QUEUE_IO_DEVICE_CONTROL EvtIoDeviceControl;
 Assume your raw touch data from I2C is

The handler validates input, updates driver’s calibration structure, saves to registry, and optionally applies it to the hardware. Calibration parameters could be stored in the registry, e

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