linux-kernel - Re: [PATCH] driver:st1633: fixed multitouch incorrect coordinates

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Message-ID: <9de64de8-7581-808d-e930-315aca05687c@posteo.de>
Date:   Mon, 21 Oct 2019 09:10:23 +0200
From:   Martin Kepplinger <martink@...teo.de>
To:     Dixit Parmar <dixitparmar19@...il.com>
Cc:     dmitry.torokhov@...il.com, rydberg@...math.org,
        kuninori.morimoto.gx@...esas.com, robh@...nel.org,
        matthias.fend@...fvision.net, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] driver:st1633: fixed multitouch incorrect coordinates

On 20.10.19 10:29, Dixit Parmar wrote:
> Any review comments for this?
> Or it should be merged?
> 
> Thanks.

My comment and tag is there. This fixes multitouch and should be merged.

                              martin


> 
> 
> On Thu, Aug 22, 2019 at 02:08:14PM +0200, Martin Kepplinger wrote:
>> Am 19.08.2019 12:08 schrieb Dixit Parmar:
>>> From: Dixit Parmar <dixitparmar19@...il.com>
>>>
>>> For Sitronix st1633 multi-touch controller driver the co-ordinates
>>> reported
>>> for multiple fingers were wrong.
>>>
>>> So the below mentioned bug was filed,
>>> Bugzilla Bug ID: 204561
>>>
>>> While reading co-ordinates from specified I2C registers, the X & Y
>>> co-ordinates should be read from proper I2C address for particular
>>> finger as
>>> specified in chip specific datasheet.
>>>
>>> for single touch this logic is working fine. However, for multi-touch
>>> scenario the logic of reading data from data buffer has issues.
>>>
>>> This patch fixes the reading logic from data buffer.
>>>
>>> Previous logic:
>>> * Offset of X & Y Lower byte coordinate is increased by i no. only(by 1
>>> Byte)
>>>   for each finger.
>>>
>>> New logic:
>>> * The logic of reading X & Y Lower Byte coordinate needs to be increased
>>>   by i+y for each time/finger.
>>>
>>> Signed-off-by: Dixit Parmar <dixitparmar19@...il.com>
>>> ---
>>>  drivers/input/touchscreen/st1232.c | 6 ++++--
>>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/input/touchscreen/st1232.c
>>> b/drivers/input/touchscreen/st1232.c
>>> index 3492339..1139714 100644
>>> --- a/drivers/input/touchscreen/st1232.c
>>> +++ b/drivers/input/touchscreen/st1232.c
>>> @@ -81,8 +81,10 @@ static int st1232_ts_read_data(struct st1232_ts_data
>>> *ts)
>>>  	for (i = 0, y = 0; i < ts->chip_info->max_fingers; i++, y += 3) {
>>>  		finger[i].is_valid = buf[i + y] >> 7;
>>>  		if (finger[i].is_valid) {
>>> -			finger[i].x = ((buf[i + y] & 0x0070) << 4) | buf[i + 1];
>>> -			finger[i].y = ((buf[i + y] & 0x0007) << 8) | buf[i + 2];
>>> +			finger[i].x = ((buf[i + y] & 0x0070) << 4) |
>>> +					buf[i + y + 1];
>>> +			finger[i].y = ((buf[i + y] & 0x0007) << 8) |
>>> +					buf[i + y + 2];
>>
>> Seems like you're right. It's simply +1 (for x) and +2 (for y) from the
>> high-byte locations.
>> Not sure how that went wrong.
>>
>> Thank you,
>>
>> Reviewed-by: Martin Kepplinger <martink@...teo.de>
>>
>>
>>>
>>>  			/* st1232 includes a z-axis / touch strength */
>>>  			if (ts->chip_info->have_z)
>>