linux-kernel - Re: [PATCH v3 7/9] input: elants: support 0x66 reply opcode for reporting touches

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Message-ID: <e3c9bf37-2a47-43f4-bd4b-13724000dbd2@gmail.com>
Date:   Sun, 26 Apr 2020 08:21:07 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:     Henrik Rydberg <rydberg@...math.org>,
        James Chen <james.chen@....com.tw>,
        Johnny Chuang <johnny.chuang@....com.tw>,
        Rob Herring <robh+dt@...nel.org>,
        Scott Liu <scott.liu@....com.tw>,
        David Heidelberg <david@...t.cz>, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 7/9] input: elants: support 0x66 reply opcode for
 reporting touches

26.04.2020 08:15, Dmitry Torokhov пишет:
> On Mon, Apr 13, 2020 at 03:32:26PM +0200, Michał Mirosław wrote:
>> From: Dmitry Osipenko <digetx@...il.com>
>>
>> eKTF3624 touchscreen firmware uses two variants of the reply opcodes for
>> reporting touch events: one is 0x63 (used by older firmware) and other is
>> 0x66 (used by newer firmware). The 0x66 variant is equal to 0x63 of
>> eKTH3500, while 0x63 needs small adjustment of the touch pressure value.
>>
>> Nexus 7 tablet device has eKTF3624 touchscreen and it uses 0x66 opcode for
>> reporting touch events, let's support it now. Other devices, eg. ASUS TF300T,
>> use 0x63.
>>
>> Note: CMD_HEADER_REK is used for replying to calibration requests, it has
>> the same 0x66 opcode number which eKTF3624 uses for reporting touches.
>> The calibration replies are handled separately from the the rest of the
>> commands in the driver by entering into ELAN_WAIT_RECALIBRATION state
>> and thus this change shouldn't change the old behavior.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@...il.com>
>> Tested-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
>> Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
>> ---
>>  drivers/input/touchscreen/elants_i2c.c | 11 ++++++++++-
>>  1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
>> index 2b936e920874..9751139e8507 100644
>> --- a/drivers/input/touchscreen/elants_i2c.c
>> +++ b/drivers/input/touchscreen/elants_i2c.c
>> @@ -60,6 +60,15 @@
>>  #define QUEUE_HEADER_NORMAL	0X63
>>  #define QUEUE_HEADER_WAIT	0x64
>>  
>> +/*
>> + * Depending on firmware version, eKTF3624 touchscreens may utilize one of
>> + * these opcodes for the touch events: 0x63 and 0x66. The 0x63 is used by
>> + * older firmware version and differs from 0x66 such that touch pressure
>> + * value needs to be adjusted.
> 
> Who is responsible for the adjustment? Where does it happen?


Please see the patch #2 ("support old touch report format") which adds
support for parsing of the older packet format that requires the
pressure value adjustment.