Re: [External] Using IIO to export laptop palm-sensor and lap-mode info to userspace?

Hi

On 2020-10-12 8:13 a.m., Hans de Goede wrote:

Hi,

On 10/9/20 4:19 AM, Jeff LaBundy wrote:

quoted

Hi Hans,

<snip>

quoted

quoted

quoted

I just wanted to chime in and confirm that we do have at least one
precedent for these being in input (keyboard/iqs62x-keys) and not
iio so I agree with Jonathan here. My argument is that we want to
signal binary events (user grabbed onto or let go of the handset)
rather than deliver continuous data.

I was curious what keycode you are using for this, but I see
that the keycodes come from devicetree, so I guess I should
just ask: what keycode are you using for this ?

The idea here was that a vendor might implement their own daemon
that interprets any keycode of their choice, hence leaving the
keycodes assignable via devicetree.

This particular device also acts as a capacitive/inductive button
sensor, and these applications were the primary motivation for it
landing in input with its status bits mapped to keycodes.

I don't think there are any keycodes that exist today that would
universally work for this application. The couple that seem most
closely related (e.g. KEY_WLAN or KEY_RFKILL) are typically used
for disabling the adapter entirely or for airplane mode (please
correct me if I'm wrong).

You're right (aka not wrong), KEY_WLAN and KEY_RFKILL are used to
toggle wireless radios on/off and re-using them for some SAR
purpose would lead to nothing but confusion. We really need to
define some standard *new* event-codes for this, such as e.g.
the proposed SW_LAP_PROXIMITY and SW_PALMREST_PROXIMITY.

quoted

To that end, I'm keen to see how this interface unfolds because
SAR detection tends to be an available mode of operation for
several of the capacitive touch devices I've been working with.

I guess that for touchscreens at least (which are on the front),
using the existing SW_FRONT_PROXIMITY would make the most sense.

I've been looking at implementing this and I'm missing something - and I 
think it's probably something obvious so hoping someone can short cut me 
to the answer. Hope it's OK to do that in this thread (I removed the 
linux-iio list as I'm assuming they won't be interested)

I've added the new event codes to input-event-codes.h and updated 
mode_devicetable.h

In the thinkpad_acpi.c driver I initialise the device:

    tpacpi_sw_dev = input_allocate_device();
    if (!tpacpi_sw_dev)
            return -ENOMEM;
    tpacpi_sw_dev->name = "Thinkpad proximity switches";
    tpacpi_sw_dev->phys = TPACPI_DRVR_NAME "/input1";
    tpacpi_sw_dev->id.bustype = BUS_HOST;
    tpacpi_sw_dev->id.vendor = thinkpad_id.vendor;
    tpacpi_sw_dev->id.product = TPACPI_HKEY_INPUT_PRODUCT;
    tpacpi_sw_dev->id.version = TPACPI_HKEY_INPUT_VERSION;
    tpacpi_sw_dev->dev.parent = &tpacpi_pdev->dev;

    if (has_palmsensor) {
       input_set_capability(tpacpi_sw_dev, EV_SW, SW_PALMREST_PROXIMITY);
       input_report_switch(tpacpi_sw_dev,SW_PALMREST_PROXIMITY, 
palmsensor_state);
    }

    if (has_lapsensor) {
         input_set_capability(tpacpi_sw_dev, EV_SW, SW_LAP_PROXIMITY);
         input_report_switch(tpacpi_sw_dev, SW_LAP_PROXIMITY, 
lapsensor_state);
    }
    err = input_register_device(tpacpi_sw_dev);

If the sensor triggers I update the inputdevice with:
    input_report_switch(tpacpi_sw_dev, SW_PALMREST_PROXIMITY, new_state);
    input_sync(tpacpi_sw_dev);
<similar for lapmode>

However I'm not seeing the change when I look under evtest, though I do 
see the new sensors show up:

    [banther@localhost linux]$ sudo evtest
    No device specified, trying to scan all of /dev/input/event*
    Available devices:
    /dev/input/event0:	Sleep Button
    /dev/input/event1:	Lid Switch
    /dev/input/event2:	Power Button
    /dev/input/event3:	AT Translated Set 2 keyboard
    /dev/input/event4:	TPPS/2 Elan TrackPoint
    /dev/input/event5:	SYNA8004:00 06CB:CD8B Mouse
    /dev/input/event6:	SYNA8004:00 06CB:CD8B Touchpad
    /dev/input/event7:	Video Bus
    /dev/input/event8:	Thinkpad proximity switches
    /dev/input/event9:	PC Speaker
    /dev/input/event10:	Integrated Camera: Integrated C
    /dev/input/event11:	sof-hda-dsp Headset Jack
    /dev/input/event12:	sof-hda-dsp Mic
    /dev/input/event13:	sof-hda-dsp Headphone
    /dev/input/event14:	sof-hda-dsp HDMI/DP,pcm=3
    /dev/input/event15:	sof-hda-dsp HDMI/DP,pcm=4
    /dev/input/event16:	sof-hda-dsp HDMI/DP,pcm=5
    /dev/input/event17:	ThinkPad Extra Buttons
    Select the device event number [0-17]: 8
    Input driver version is 1.0.1
    Input device ID: bus 0x19 vendor 0x17aa product 0x5054 version 0x4101
    Input device name: "Thinkpad proximity switches"
    Supported events:
      Event type 0 (EV_SYN)
      Event type 5 (EV_SW)
        Event code 17 (?) state 0
        Event code 18 (?) state 0
    Properties:
    Testing ... (interrupt to exit)

The state for both sensors is supposed to be 1.
I did download and rebuild evtest and fixed the (?), but haven't figured 
out why the state is wrong. It seemed related to the number of keys 
which I found odd.

Any suggestions from what I'm missing, or have done wrong, or where I 
should dig next? What's the recommended way of testing my implementation?

Thanks
Mark