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References: <20211021095107.116292-1-alistair@alistair23.me>
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From:   Benjamin Tissoires <benjamin.tissoires@redhat.com>
Date:   Thu, 21 Oct 2021 11:58:21 +0200
Message-ID: <CAO-hwJKXQsEU-i41EB5LyB3cSrFG9y+6WsQ8XuryL5AniCrM_Q@mail.gmail.com>
Subject: Re: [PATCH v12 1/3] HID: quirks: Allow inverting the absolute X/Y values
To:     Alistair Francis <alistair@alistair23.me>
Cc:     Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        dl-linux-imx <linux-imx@nxp.com>, Jiri Kosina <jikos@kernel.org>,
        "open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
        DTML <devicetree@vger.kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Alistair Francis <alistair23@gmail.com>
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On Thu, Oct 21, 2021 at 11:51 AM Alistair Francis
<alistair@alistair23.me> wrote:
>
> Add a HID_QUIRK_XY_INVERT quirk that can be used to invert the X/Y
> values.
>
> Signed-off-by: Alistair Francis <alistair@alistair23.me>
> ---
>  drivers/hid/hid-input.c | 7 +++++++
>  include/linux/hid.h     | 1 +
>  2 files changed, 8 insertions(+)
>
> diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> index 4b5ebeacd283..0a9634473940 100644
> --- a/drivers/hid/hid-input.c
> +++ b/drivers/hid/hid-input.c
> @@ -1328,6 +1328,13 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
>
>         input = field->hidinput->input;
>
> +       if (*quirks & HID_QUIRK_XY_INVERT) {
> +               if (usage->type == EV_ABS &&
> +                       (usage->code == ABS_X || usage->code == ABS_Y)) {

I think I would prefer to have one quirk per axis if we go this route.

Cheers,
Benjamin

> +                       value = field->logical_maximum - value;
> +               }
> +       }
> +
>         if (usage->hat_min < usage->hat_max || usage->hat_dir) {
>                 int hat_dir = usage->hat_dir;
>                 if (!hat_dir)
> diff --git a/include/linux/hid.h b/include/linux/hid.h
> index 9e067f937dbc..a6e91ee5b3de 100644
> --- a/include/linux/hid.h
> +++ b/include/linux/hid.h
> @@ -349,6 +349,7 @@ struct hid_item {
>  /* BIT(9) reserved for backward compatibility, was NO_INIT_INPUT_REPORTS */
>  #define HID_QUIRK_ALWAYS_POLL                  BIT(10)
>  #define HID_QUIRK_INPUT_PER_APP                        BIT(11)
> +#define HID_QUIRK_XY_INVERT                    BIT(12)
>  #define HID_QUIRK_SKIP_OUTPUT_REPORTS          BIT(16)
>  #define HID_QUIRK_SKIP_OUTPUT_REPORT_ID                BIT(17)
>  #define HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP BIT(18)
> --
> 2.31.1
>