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Date:   Wed,  5 May 2021 22:43:55 +0000
From:   Jonathan =?utf-8?Q?Neusch=C3=A4fer?= <j.ne@posteo.net>
To:     Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Cc:     linux-input@vger.kernel.org, Ash Logan <ash@heyquark.com>,
        Jonathan =?utf-8?Q?Neusch=C3=A4fer?= <j.ne@posteo.net>,
        Jiri Kosina <jikos@kernel.org>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] HID: wiiu-drc: Implement touch reports
Message-ID: <YJMfq9MbY2guEhpv@latitude>
References: <20210502232836.26134-1-linkmauve@linkmauve.fr>
 <20210502232836.26134-3-linkmauve@linkmauve.fr>
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Hi,

some more comments below. Enjoy :)

On Mon, May 03, 2021 at 01:28:33AM +0200, Emmanuel Gil Peyrot wrote:
> There is a 100=C3=97200 inaccessible border on each side, and the Y axis =
is
> inverted, these are the two main quirks of this touch panel.

Does that mean 100 px borders left and right, and 200 px borders top and
bottom?

100=C3=97200 evokes the image of a rectangle of that size, which I found
confusing for a moment.

>=20
> I=E2=80=99ve been testing with weston-simple-touch mostly, but it also wi=
th the
> rest of Weston.
>=20
> Signed-off-by: Ash Logan <ash@heyquark.com>
> Signed-off-by: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
> ---
>  drivers/hid/hid-wiiu-drc.c | 83 +++++++++++++++++++++++++++++++++++---
>  1 file changed, 78 insertions(+), 5 deletions(-)
>=20
> diff --git a/drivers/hid/hid-wiiu-drc.c b/drivers/hid/hid-wiiu-drc.c
> index 018cbdb53a2c..77e70827c37d 100644
> --- a/drivers/hid/hid-wiiu-drc.c
> +++ b/drivers/hid/hid-wiiu-drc.c
> @@ -49,13 +49,27 @@
> =20
>  #define BUTTON_POWER	BIT(25)
> =20
> +/* Touch constants */
> +/* Resolution in pixels */
> +#define RES_X		854
> +#define RES_Y		480
> +/* Display/touch size in mm */
> +#define WIDTH		138
> +#define HEIGHT		79
> +#define NUM_TOUCH_POINTS 10
> +#define MAX_TOUCH_RES	(1 << 12)
> +#define TOUCH_BORDER_X	100
> +#define TOUCH_BORDER_Y	200

[...]
> +	/* touch */
> +	/* Average touch points for improved accuracy. */
> +	x =3D y =3D 0;
> +	for (i =3D 0; i < NUM_TOUCH_POINTS; i++) {
> +		base =3D 36 + 4 * i;
> +
> +		x +=3D ((data[base + 1] & 0xF) << 8) | data[base];
> +		y +=3D ((data[base + 3] & 0xF) << 8) | data[base + 2];
> +	}
> +	x /=3D NUM_TOUCH_POINTS;
> +	y /=3D NUM_TOUCH_POINTS;

Given that there are 10 possible touch points: Does the gamepad actually
support multitouch (usefully)?

If so, I think it would be better to report all touch points
individually to userspace, to allow for multitouch gestures;
userspace can still implement averaging if desired.


Thanks,
Jonathan

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