Linux实现电容屏驱动研究（linux电容屏驱动）
Recently，capacitive touchscreen technology has become increasingly popular due to its convenience, durability, and aesthetic qualities. In fact, they’re now the most popular touchscreens on the market, used in electronic products ranging from tablets to phones to POS systems, among other things. The Linux operating system is one of the most widely-used platform for data processing and system management, but few people may know that it also supports the development and driving of the capacitive touchscreen.
Various input device sub-systems within the Linux kernel code manage the running of the capacitive touchscreen. The device driver of the capacitive touchscreen needs to match all device’s parameters so that it can communicated with the host system directly. First, vendors should prepare their own device datasheet, including the instruction and parameters of the touchscreen, as well as a sampling-rate profile that provides the data transmitting frequency and other timings related to the capacitive touchscreen.
After the touchscreen device driver is registered, it needs to be coupled with the platform and device model. This will inform the device driver of the capacitive touchscreen which controller is in use. The controller models can range from GPIO (General-Purpose Input/Output) interface to I2C (Inter-Integrated Circuit) and SPI (Serial Peripheral Interface) interface. Each touch controller model has a corresponding driver ready to be used.
Moreover, the capacitive touchscreen needs to be calibrated according to the logical resolution given by the host coordinator. The coordinates transferred from the controller to the host system will thus accurately correlate with the coordinates provided by the touchscreen panel. If the calibration is miscalculated due to a faulty handler, mismatch between the device datasheet and the actual physical resolution or other reasons, then the touchscreen may malfunction.
To cut a long story short, coding and operating a capacitive touchscreen with Linux is often complicated and requires a reasonably deep technologic understanding. Professional guidance is necessary to avoid possibly reaping little benefit. With the right expertise and knowledge, the Linux operating system can be the perfect platform to get the most out of your capacitive touchscreen.
