On Fri, May 24, 2019 at 5:13 AM 廖崇榮 [off-list ref] wrote:

Hi Benjamin,

Thanks so much for all you do for Elan touchpad.

For the width_*, I have a question for it.
Our antenna sensors fully occupied the whole touchpad PCB.

The Gap between 2 sensors are 7.5 mil (0.19mm).
That's why we did not minus one trace.

So, with the P52 I have:
[  +0.000009] max:    (3045,1731) drivers/input/mouse/elan_i2c_core.c:428
[  +0.000003] traces: (24,14) drivers/input/mouse/elan_i2c_core.c:429
[  +0.000002] size:   (98,55) drivers/input/mouse/elan_i2c_core.c:430
[  +0.000001] res:    (31,31) drivers/input/mouse/elan_i2c_core.c:431

calculated size (max/res): 98 x 56 mm
true size, as measured: 101 x 60 mm

Which gives (without the minus 1):
width_x = max_x / x_traces = 3045 / 24 = 126.875 -> 3.9885 mm
width_y = max_y / y_traces = 1731 / 14 = 123.643 -> 4.0927 mm

-> this gives a total size of the touchpad of: 96 x 57 mm (width_x *
24, width_y * 14)

With the minus 1:
width_x = max_x / x_traces = 3045 / 23 = 132.391 -> 4.2707 mm
width_y = max_y / y_traces = 1731 / 14 = 133.154 -> 4.2953 mm

-> this gives a total size of the touchpad of: 102 x 60 mm (width_x *
24, width_y * 14)
and considering traces-1: 98 x 56 mm

Removing 1 to the number of traces gave a squarer values in rows and
columns, and this is what is done in the PS/2 driver.
Also, going back to the size of the touchpad gives a better value when
removing 1 on the *traces.
So maybe when forwarding the properties we should remove one there in
the PS/2 driver?

Cheers,
Benjamin