Kmdf Hid Minidriver For Touch I2c Device Calibration -

For sealed systems, consider writing coefficients directly to the I2C device's EEPROM. This requires an additional vendor-specific I2C command. Part 6: User-Mode Calibration Application – The Companion Tool Your KMDF driver alone cannot perform calibration; it only applies it. A user-mode application must guide the user, collect points, compute coefficients, and call DeviceIoControl .

WDFKEY hKey; WdfDeviceOpenRegistry(Device, PLUGPLAY_REGKEY_DEVICE, &hKey); // Read REG_BINARY "CalibCoeffs" -> store in device context WdfRegistryClose(hKey); When user-mode sends SET_COEFFS , write back immediately to the registry. kmdf hid minidriver for touch i2c device calibration

switch(IoControlCode) case IOCTL_TOUCH_CALIBRATE_SET_COEFFS: // Lock mutex, copy coefficients into device context, apply to next touch // Store in registry via WdfRegistry break; case IOCTL_TOUCH_CALIBRATE_GET_RAW: // Temporarily bypass calibration, read raw I2C registers, return break; A user-mode application must guide the user, collect

Define a custom IOCTL in your header:

// Indicate this is a HID minidriver WdfDeviceInitSetDeviceType(DeviceInit, FILE_DEVICE_KEYBOARD); // Or appropriate type // Set up power management for I2C wake WdfDeviceInitSetPowerPolicyOwnership(DeviceInit, FALSE); and call DeviceIoControl . WDFKEY hKey

VOID ApplyCalibration(PTOUCH_POINT RawPoint, PTOUCH_POINT CalibratedPoint)