[PATCH v2 0/4] Add support for the Cypress cyttsp5

Alistair Francis
2021-11-03T11:48:43Z

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/20180703094309.18514-1-mylene.josserand@bootlin.com/
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,tt21000.yaml | 92 ++
arch/arm/boot/dts/imx7d-remarkable2.dts | 89 ++
arch/arm/configs/imx_v6_v7_defconfig | 1 +
drivers/input/touchscreen/Kconfig | 14 +
drivers/input/touchscreen/Makefile | 1 +
drivers/input/touchscreen/cyttsp5.c | 1135 +++++++++++++++++
6 files changed, 1332 insertions(+)
create mode 100644 Documentation/devicetree/bindings/input/touchscreen/cypress,tt21000.yaml
create mode 100644 drivers/input/touchscreen/cyttsp5.c

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2.31.1