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

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Date:   Sat, 25 Apr 2020 22:15:03 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:     Dmitry Osipenko <digetx@...il.com>,
        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

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?

Thanks.

-- 
Dmitry