[0/4] Add support for the Cypress cyttsp5

Message

Alistair Francis Oct. 25, 2021, 11:42 a.m. UTC

This patch series builds on top of [1] and adds support for the cyttsp5
touchscreen controller for the reMarkable 2.

I first tried to add an I2C HID device. Although the cyttsp5 has some HID
looking aspects it is not HID compatible. Just in trying to probe the device
I found:
 - The HID descriptor has extra padding
 - The HID descriptor sets the high bytes of the descriptor length
 - The HID descriptor has extra unrecognised tags
 - The HID reset command doesn't appear to work

I don't think there is a way to use the I2C HID framework with the cyttsp5.
For anyone interested you can see the work here [2]. In that branch though I
can only obtain a HID descriptor, nothing else works without more core
changes.

So instead I rebased the series from [1]. Converted to the new yaml DTS
documentation, added regulator support and fixed a x/y miscalculation bug.

1: https://lwn.net/ml/linux-kernel/[e-mail]/
2: https://github.com/alistair23/linux/commits/rM2-mainline-cyttsp5-hid

Alistair Francis (2):
  ARM: imx_v6_v7_defconfig: Enable the cyttsp5 touchscreen
  ARM: dts: imx7d: remarkable2: Enable the cyttsp5

Mylène Josserand (2):
  Input: Add driver for Cypress Generation 5 touchscreen
  Documentation: DT: bindings: input: Add documentation for cyttsp5

 .../input/touchscreen/cypress,cyttsp5.yaml    |   72 ++
 arch/arm/boot/dts/imx7d-remarkable2.dts       |   88 ++
 arch/arm/configs/imx_v6_v7_defconfig          |    1 +
 drivers/input/touchscreen/Kconfig             |   14 +
 drivers/input/touchscreen/Makefile            |    1 +
 drivers/input/touchscreen/cyttsp5.c           | 1129 +++++++++++++++++
 6 files changed, 1305 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/cypress,cyttsp5.yaml
 create mode 100644 drivers/input/touchscreen/cyttsp5.c