chipone_tddi — ChipOne ICNL9922C TDDI touchscreen driver

Out-of-tree Linux kernel module for the ChipOne ICNL9922C TDDI touch controller, as used in the KONKR Pocket FIT (Qualcomm SM8650) handheld. Built for use with ROCKNIX on its mainline-based kernel (7.0.x).

Provenance

This is a port of ChipOne's cts_* vendor driver, taken from MotorolaMobilityLLC/motorola-kernel-modules, path drivers/input/touchscreen/chipone_tddi_mmi_v2 (tag android-14-release-u4ui34.8-28-1). You can brows the original source here. The original copyright and SPDX-License-Identifier headers are retained in each source file.

It was written against a downstream Android kernel (~5.10/6.1 GKI); this fork makes it build and load as an out-of-tree module on mainline Linux 7.0.x.

Changes from upstream

• API drift fixes for mainline 7.0: <linux/unaligned.h>; dropped linux/mmi_wake_lock.h; single-arg i2c .probe and void .remove; class_create() (1-arg); PDE_DATA() -> pde_data(); no_llseek -> noop_llseek; MODULE_IMPORT_NS("...") string form; removed the module-unexported irq_to_desc() debug use; dropped the driver's private get/put_unaligned_le24/be24 (now provided by the kernel).
• Disabled charger-detect and earjack-detect (not wired on this hardware).

Build

Configuration is set via the Kbuild ccflags:

• CONFIG_CTS_I2C_HOST — I²C transport
• CONFIG_CTS_IC_NAME_ICNL9922C — target IC
• CFG_CTS_WRAP_X — invert the X axis (the KONKR panel is mounted rotated 90°)

Out-of-tree against an installed kernel:

make KDIR=/path/to/kernel/build

Devicetree

The controller sits on &i2c4 (i2c@a90000) at address 0x48, IRQ on TLMM gpio 162, reset on TLMM gpio 161:

&i2c4 {
    touchscreen@48 {
        compatible = "chipone-tddi";
        reg = <0x48>;
        interrupt-parent = <&tlmm>;
        interrupts = <162 IRQ_TYPE_EDGE_FALLING>;
        chipone,irq-gpio = <&tlmm 162 GPIO_ACTIVE_HIGH>;
        chipone,rst-gpio = <&tlmm 161 GPIO_ACTIVE_HIGH>;
        chipone,x-res = <1080>;
        chipone,y-res = <1920>;
        pinctrl-names = "default";
        pinctrl-0 = <&ts_irq_default>, <&ts_reset_default>;
        status = "okay";
    };
};

License

GPL-2.0 (see LICENSE). Derivative of GPL-2.0 vendor source; license retained.