On Thu, Dec 16, 2021 at 3:30 PM Tim Harvey <tharvey@xxxxxxxxxxxxx> wrote: > > 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(-) > > -- Any feedback on this? The other approach I posted an RFC series for was to add a completely new driver [1] Best regards, Tim [1] https://patchwork.kernel.org/project/linux-input/list/?series=596975
