Hi -----Original Message----- From: Benjamin Tissoires [mailto:benjamin.tissoires@xxxxxxxxxx] Sent: Friday, May 24, 2019 3:06 PM To: 廖崇榮 Cc: Dmitry Torokhov; Rob Herring; Aaron Ma; Hans de Goede; open list:HID CORE LAYER; lkml; devicetree@xxxxxxxxxxxxxxx Subject: Re: [PATCH v2 09/10] Input: elan_i2c - correct the width/size base value On Fri, May 24, 2019 at 5:13 AM 廖崇榮 <kt.liao@xxxxxxxxxx> 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 I list layout information of P52 touchpad as below. Physical size : 99 x 58 mm Active Area size : ~ 97 * 56 mm, (boarding is 1.008mm for each side) Sensor layout: X Pitch : 4.0286 mm Y Pitch : 4.0147 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? Removing 1 trace may be better for some of previous touchpad. (depending on sensor pattern) mk_* indicate the number of trace which is touched, and it's not a precise value. I think the usability won't change too much whether removing one trace. PS/2 have supported plenty of touchpad. It's better to remain the same. Thanks KT Cheers, Benjamin > > > Thanks > KT > -----Original Message----- > From: Benjamin Tissoires [mailto:benjamin.tissoires@xxxxxxxxxx] > Sent: Tuesday, May 21, 2019 9:27 PM > To: Dmitry Torokhov; KT Liao; Rob Herring; Aaron Ma; Hans de Goede > Cc: linux-input@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > devicetree@xxxxxxxxxxxxxxx; Benjamin Tissoires > Subject: [PATCH v2 09/10] Input: elan_i2c - correct the width/size > base value > > *_traces are the number of antennas. width_* is thus the space between > 2 antennas. Which means, we should subtract 1 to the number of > antennas to divide the touchpad by the number of holes between each antenna. > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> > > -- > > new in v2 > --- > drivers/input/mouse/elan_i2c_core.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/input/mouse/elan_i2c_core.c > b/drivers/input/mouse/elan_i2c_core.c > index 6f4feedb7765..3375eaa9a72e 100644 > --- a/drivers/input/mouse/elan_i2c_core.c > +++ b/drivers/input/mouse/elan_i2c_core.c > @@ -398,8 +398,8 @@ static int elan_query_device_parameters(struct > elan_tp_data *data) > if (error) > return error; > } > - data->width_x = data->max_x / x_traces; > - data->width_y = data->max_y / y_traces; > + data->width_x = data->max_x / (x_traces - 1); > + data->width_y = data->max_y / (y_traces - 1); > > if (device_property_read_u32(&client->dev, > "touchscreen-x-mm", &x_mm) || > -- > 2.21.0 >
