[PATCH v7 0/4] Driver for Apple Z2 touchscreens.

[Sasha Finkelstein via B4 Relay <devnull+fnkl.kernel.gmail.com@kernel.org>]

Hi.

This series adds support for Apple touchscreens using the Z2 protocol.
Those are used as the primary touchscreen on mobile Apple devices, and for the
touchbar on laptops using the M-series chips. (T1/T2 laptops have a coprocessor
in charge of speaking Z2 to the touchbar).

Originally sent as a RFC at https://lore.kernel.org/all/20230223-z2-for-ml-v1-0-028f2b85dc15@gmail.com/
The changes since then mostly address the review feedback, but also
add another machine that has this specific controller.

Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
---
Changes in v7:
- Added a dependency on ARCH_APPLE to prevent potential confusion on x86
- Link to v6: https://lore.kernel.org/r/20250205-z2-v6-0-cc60cbee1d5b@gmail.com

Changes in v6:
- Went back to build_cal_blob returning an allocated buffer, other fixes.
- Link to v5: https://lore.kernel.org/r/20250118-z2-v5-0-6d38b2582169@gmail.com

Changes in v5:
- Added missing \ns, removed 4kb-ish of wasted ram
- Link to v4: https://lore.kernel.org/r/20250115-z2-v4-0-d7361ab16ba0@gmail.com

Changes in v4:
- Dropped another allocation, other fixes.
- Link to v3: https://lore.kernel.org/r/20250112-z2-v3-0-5c0e555d3df1@gmail.com

Changes in v3:
- Tx/Rx buffers used in interrupt handler are now allocated in probe and reused
- Other various style fixes
- Link to v2: https://lore.kernel.org/r/20241128-z2-v2-0-76cc59bbf117@gmail.com

Changes in v2:
- In a separate patch, fixed an issue that prevented the SPI controller
  from using GPIO CS, and as such, moved the hardware quirk to there
- Went back to uploading the firmware in probe() instad of open()
- Other changes addressing the review feedback
- Link to v1: https://lore.kernel.org/r/20241126-z2-v1-0-c43c4cc6200d@gmail.com

---
Sasha Finkelstein (4):
      dt-bindings: input: touchscreen: Add Z2 controller
      input: apple_z2: Add a driver for Apple Z2 touchscreens
      arm64: dts: apple: Add touchbar digitizer nodes
      MAINTAINERS: Add entries for Apple Z2 touchscreen driver

 .../input/touchscreen/apple,z2-multitouch.yaml     |  70 +++
 MAINTAINERS                                        |   2 +
 arch/arm64/boot/dts/apple/t8103-j293.dts           |  27 ++
 arch/arm64/boot/dts/apple/t8103.dtsi               |  19 +
 arch/arm64/boot/dts/apple/t8112-j493.dts           |  23 +
 arch/arm64/boot/dts/apple/t8112.dtsi               |  14 +
 drivers/input/touchscreen/Kconfig                  |  13 +
 drivers/input/touchscreen/Makefile                 |   1 +
 drivers/input/touchscreen/apple_z2.c               | 473 +++++++++++++++++++++
 9 files changed, 642 insertions(+)
---
base-commit: b62cef9a5c673f1b8083159f5dc03c1c5daced2f
change-id: 20241124-z2-c012b528ea0d