[PATCH v3 0/5] Support zinitix touch modes 0 and 1, dt changes to Galaxy J6 (j6lte)

[Kaustabh Chakraborty <kauschluss@disroot.org>]

The zinitix family of touchscreens support at least three modes, called
0, 1, and 2. At least some digitizers (including, but not limited to
ZT7548) are able to support multiple modes. Currently, the driver in
linux supports mode 2 only. This series aims to add support for modes 0
and 1, accompanied with necessary architectural changes.

Among other things, perhaps the biggest difference between multiple
modes is how the touch report schema is laid out. Modes may skip
reporting certain properties such as touch width and pressure. For more
implementation details, the android driver [1] can be referred to, which
was also the primary reference material for these changes.

The last patch is for the Samsung Galaxy J6 (samsung-j6lte), which has a
zinitix touchscreen digitizer. By default, mode 2 is assumed for the
touchscreen, however the downstream kernel driver [1] for this device
uses mode 0 by default. This creates an issue with aftermarket
digitizers where mode 2 implementation isn't available simply because
it's not required by the driver downstream.

This last patch needs to be accepted into next only when the former
patches are in next.  

[1] https://github.com/samsungexynos7870/android_kernel_samsung_exynos7870/blob/master/drivers/input/touchscreen/zinitix/zinitix_zt75xx_ts.c

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
---
Changes in v3:
- Add missing review trailers from v1
- Link to v2: https://patch.msgid.link/20260731-zinitix-modes-v2-0-ffe2ec9a9031@disroot.org

Changes in v2:
- Change condition for calling zinitix_report_finger() (Dmitry Torokhov)
- Use function pointer for read_status_mode* switching (Dmitry Torokhov)
- Link to v1: https://patch.msgid.link/20260724-zinitix-modes-v1-0-f6df7d86a878@disroot.org

---
Kaustabh Chakraborty (5):
      Input: zinitix - check all available fingers for every touch event
      Input: zinitix - do not ignore non-moving fingers
      Input: zinitix - add support for modes 0 and 1
      dt-bindings: input/ts/zinitix: document mode 0
      arm64: dts: exynos7870-j6lte: set mode 0 as default for zinitix touchscreen

 .../bindings/input/touchscreen/zinitix,bt400.yaml  |   4 +-
 arch/arm64/boot/dts/exynos/exynos7870-j6lte.dts    |   2 +
 drivers/input/touchscreen/zinitix.c                | 141 +++++++++++++++++++--
 3 files changed, 132 insertions(+), 15 deletions(-)
---
base-commit: 290aaf24a551d5a0dce037e3fab30820f9113a10
change-id: 20260723-zinitix-modes-9c4d409b9ee3

Best regards,
--  
Kaustabh Chakraborty <kauschluss@disroot.org>