Re: [PATCH v7 0/4] Add support for the Cypress cyttsp5

From: Alistair Francis <alistair23@gmail.com>
To: Alistair Francis <alistair@alistair23.me>
Cc: linux-input <linux-input@vger.kernel.org>,
	devicetree <devicetree@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Henrik Rydberg <rydberg@bitmath.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Andreas Kemnade <andreas@kemnade.info>
Subject: Re: [PATCH v7 0/4] Add support for the Cypress cyttsp5
Date: Wed, 20 Apr 2022 22:25:06 +1000	[thread overview]
Message-ID: <CAKmqyKP5CRDx4acc6yg9SwADaGTNqKmDUrBs2ODXR30OZuunoA@mail.gmail.com> (raw)
In-Reply-To: <20220323120021.361137-1-alistair@alistair23.me>

On Wed, Mar 23, 2022 at 10:00 PM Alistair Francis
<alistair@alistair23.me> wrote:
>
> 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.

The DT bindings have been reviewed, any comments on the driver
implementation? It has been tested on a few different devices

Alistair

>
> 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
>
> v7:
>  - Fix device tree warnings
> v6:
>  - Use reg for the button properties
> v5:
>  - Address review comments from v4
>
> Alistair Francis (4):
>   Input: Add driver for Cypress Generation 5 touchscreen
>   dt-bindings: input: Add Cypress TT2100 touchscreen controller
>   ARM: imx_v6_v7_defconfig: Enable the cyttsp5 touchscreen
>   ARM: dts: imx7d-remarkable2: Enable the cyttsp5
>
>  .../input/touchscreen/cypress,tt21000.yaml    | 101 ++
>  arch/arm/boot/dts/imx7d-remarkable2.dts       | 100 ++
>  arch/arm/configs/imx_v6_v7_defconfig          |   1 +
>  drivers/input/touchscreen/Kconfig             |  16 +
>  drivers/input/touchscreen/Makefile            |   1 +
>  drivers/input/touchscreen/cyttsp5.c           | 902 ++++++++++++++++++
>  6 files changed, 1121 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/touchscreen/cypress,tt21000.yaml
>  create mode 100644 drivers/input/touchscreen/cyttsp5.c
>
> --
> 2.35.1
>