18.05.2020 07:05, Dmitry Torokhov пишет:

On Sun, Apr 26, 2020 at 07:47:52PM +0200, Michał Mirosław wrote:

quoted

From: Dmitry Osipenko <digetx@gmail.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.

Is it possible to know what format a device will use by querying it at
probe time?

I guess only somebody from Elan could answer this question. AFAIK,
neither touchscreen firmware sources nor technical documentation aren't
publicly available.

Downstream kernel driver is the only source of information in our case
and it does the same thing as we do in this patch.