The DFROBOT DFR0678 [1] and DFR0550 [2] touchscreen displays are meant to be compatible with the official RaspberryPi 7in display. However instead of directly conntecting the FT5x06 touch controller to the I2C bus going to the host processor they route it through an MCU and emulate a virtual FT5x06 controller but don't do a very good job at it. The method the RaspberryPi firmware used to read the touch data is supported (which consists of reading R2 to get the number of touch points, then reading 4 bytes of data for each point in discrete I2C transactions. If you try to use the FT5x06 driver which reads all registers starting at R0 at once you will get invalid point data. Additionally the RaspberryPi displays like these do not have a touch controller IRQ so polling mode has to be added. Also additionally these controllers do not appear to send UP events so an additional patch slightly modified from the raspberry-pi kernel is used to track ID's and report up events. I'm sending this series as an RFC as I'm not really clear if this is the best approach vs just adding a new touchscreen driver (which I have prepared and will probably send in another RFC). Tim [1] - https://www.dfrobot.com/product-2193.html [2] - https://www.dfrobot.com/product-1784.html Tim Harvey (4): dt-bindings: input: touchscreen: edt-ft5x06: add poll-interval input: edt-ft5x06 - add polled input support input: edt-ft5x06 - add support for DFROBOT touch controllers input: edt-ft5x06 - Handle unreliable TOUCH_UP events .../input/touchscreen/edt-ft5x06.yaml | 7 +- drivers/input/touchscreen/edt-ft5x06.c | 144 ++++++++++++++---- 2 files changed, 123 insertions(+), 28 deletions(-) -- 2.17.1
