Windows processes touch inputs via a layered architecture. Understanding where your KMDF minidriver sits helps isolate where calibration data must be injected or applied.
This is the "glue" code. It talks to the I2C controller using the SPB (Simple Peripheral Bus) framework and reports data back to the HID Class Driver.
Here, KX1, KX2, KX3, KY1, KY2, KY3 are the coefficients of the transformation matrix. kmdf hid minidriver for touch i2c device calibration
To implement a KMDF HID minidriver for touch I2C device calibration, developers must:
To understand where our solution fits, let’s dissect the Windows HID architecture. Windows processes touch inputs via a layered architecture
This runs when the device powers up. This is the critical moment to apply calibration, as I2C devices often lose register state on power loss.
// Define your touch controller's specific command to set calibration data #define TOUCH_CMD_SET_CALIBRATION 0xA1 It talks to the I2C controller using the
Your driver's DriverEntry will create a WDFDRIVER object and register EvtDeviceAdd . Inside EvtDeviceAdd :
Common calibration models
Used when the touch surface is curved or the I2C controller has non-uniform sensitivity.
Your driver must implement methods to communicate over I2C, typically using SpbCx (Serial Peripheral Bus Framework Extension).