Hi Caleb,
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
Please clean up the commit message.
> The touch coordinates are read by shifting a value left by 3,
> this is incorrect and effectively causes the coordinates to
> be half of the correct value.
>
> Shift by 4 bits instead to report the correct value.
>
> This matches downstream examples, and has been confirmed on my
> device (OnePlus 7 Pro).
The real reason is that from the register we get:
byte 3 byte 2 byte 1
+--------+--------+ +-----------------+ +-----------------+
| | | | | | |
| X[3:0] | Y[3:0] | | Y[11:4] | | X[11:4] |
| | | | | | |
+--------+--------+ +-----------------+ +-----------------+
and the 12 bit values have to fit in a 16bit variable.
The upper 8 bits (in event[2] and event[1] need to be shifted
left by '4' and not by '3' in order to leave space to the lower
4 bits (in event[3]).
>
> Signed-off-by: Caleb Connolly <caleb@xxxxxxxxxxxxx>
> ---
> drivers/input/touchscreen/s6sy761.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/touchscreen/s6sy761.c b/drivers/input/touchscreen/s6sy761.c
> index b63d7fdf0cd2..85a1f465c097 100644
> --- a/drivers/input/touchscreen/s6sy761.c
> +++ b/drivers/input/touchscreen/s6sy761.c
> @@ -145,8 +145,8 @@ static void s6sy761_report_coordinates(struct s6sy761_data *sdata,
> u8 major = event[4];
> u8 minor = event[5];
> u8 z = event[6] & S6SY761_MASK_Z;
> - u16 x = (event[1] << 3) | ((event[3] & S6SY761_MASK_X) >> 4);
> - u16 y = (event[2] << 3) | (event[3] & S6SY761_MASK_Y);
> + u16 x = (event[1] << 4) | ((event[3] & S6SY761_MASK_X) >> 4);
> + u16 y = (event[2] << 4) | (event[3] & S6SY761_MASK_Y);
the devil knows how that '3' has ended up there :)
Thanks for catching it!
Reviewed-by: Andi Shyti <andi@xxxxxxxxxxx>
Andi
