Date:   Tue, 14 Nov 2017 10:26:10 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Peter Hutterer <peter.hutterer@...-t.net>
Cc:     Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Jiri Kosina <jikos@...nel.org>,
        Mario Limonciello <Mario.Limonciello@...l.com>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] HID: input: enable Totem on the Dell Canvas 27

On Tue, Nov 14, 2017 at 06:50:43PM +1000, Peter Hutterer wrote:
> sorry, this one got stuck in my outbox.
> 
> On Fri, Nov 10, 2017 at 11:26:35AM +0100, Benjamin Tissoires wrote:
> > The Dell Canvas 27 has a tool that can be put on the surface and acts
> > as a dial. The firmware processes the detection of the tool and forward
> > regular HID reports with X, Y, Azimuth, rotation, width/height.
> > 
> > The firmware also exports Contact ID, Countact Count which may hint that
> > several totems can be used at the same time, but for now, only allow
> > one totem at a time.
> > 
> > We also ignore scan time in hid-input.c because there is not much point
> > to forward it now given that the indication of the tool being present
> > is already provided through BTN_TOOL_DIAL.
> > 
> > We need to add a new BTN_TOOL_DIAL event because the HID mapping
> > suggests that this tool is aimed at being used by the system and not
> > the applications. Also this prevents current systemd heuristics to
> > apply ID_INPUT_TOUCHSCREEN to this new type of devices.
> > 
> > I mapped Azimuth to ABS_WHEEL to somehow ressemble the Wacom Pads.
> 
> HID docs indicate this is a full tool rotation, so ABS_RZ would be more
> appropriate?
> 
> "Azimuth 
>     The counter-clockwise rotation of the cursor about the Z-axis."

Right. We night also want to consider whether we need to convert HID to
Linux values, as HID is counter-clockwise, and I suspect Linux will be
clockwise (what do we report for joysticks?), similar to what we had for
ABS_MT_ORIENTATION.

> 
> But you also say it has rotation, so this is a bit confusing now :)
> We should also use INPUT_PROP_DIRECT here.
> 
> > Last, both Width and Heigth are groupped together, the FW reports
> 
> typo: grouped
> 
> > similar values for both and we are out of ABS_* events.
> > 
> > Link: https://bugzilla.redhat.com/show_bug.cgi?id=1511846
> > 
> > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
> > ---
> > 
> > Hi,
> > 
> > This is probably v4.16 material as we are close to the merge window
> > (I wouldn't mind it applied in v4.15 though ;-P)
> 
> I'm going to be annoying here and say I'd like to figure out how to add this
> to libinput first to figure out what details can go wrong before we merge it
> and commit to this forever. Hopefully that shouldn't take that long...
> 
> Cheers,
>    Peter
> 
> > The patch does the job but we probably need to decide if the mappings
> > I chose are correct.
> > 
> > For the record, I uploaded some evemu-record traces and hid-recorder
> > traces in the RH Bz linked above to keep traces of them.
> > The interesting one is the evemu one for the totem with this patch
> > applied:
> > https://bugzilla.redhat.com/attachment.cgi?id=1350389
> > 
> > Cheers,
> > Benjamin
> > 
> >  drivers/hid/hid-input.c                | 28 +++++++++++++++++++++++++++-
> >  drivers/hid/hid-multitouch.c           | 11 +++++++++++
> >  include/linux/hid.h                    |  6 ++++++
> >  include/uapi/linux/input-event-codes.h |  1 +
> >  4 files changed, 45 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> > index 04d01b57d94c..7da72b571b7d 100644
> > --- a/drivers/hid/hid-input.c
> > +++ b/drivers/hid/hid-input.c
> > @@ -229,6 +229,7 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
> >  	case ABS_X:
> >  	case ABS_Y:
> >  	case ABS_Z:
> > +	case ABS_TOOL_WIDTH:
> >  	case ABS_MT_POSITION_X:
> >  	case ABS_MT_POSITION_Y:
> >  	case ABS_MT_TOOL_X:
> > @@ -786,13 +787,24 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
> >  			map_abs_clear(ABS_TILT_Y);
> >  			break;
> >  
> > +		case 0x3f: /* Azimuth */
> > +			map_abs_clear(ABS_WHEEL);
> > +			break;
> > +
> >  		case 0x33: /* Touch */
> > -		case 0x42: /* TipSwitch */
> >  		case 0x43: /* TipSwitch2 */
> >  			device->quirks &= ~HID_QUIRK_NOTOUCH;
> >  			map_key_clear(BTN_TOUCH);
> >  			break;
> >  
> > +		case 0x42: /* TipSwitch */
> > +			if (field->application == HID_GD_SYSTEM_MULTIAXIS) {
> > +				map_key_clear(BTN_TOOL_DIAL);
> > +			} else {
> > +				device->quirks &= ~HID_QUIRK_NOTOUCH;
> > +				map_key_clear(BTN_TOUCH);
> > +			}
> > +			break;
> >  		case 0x44: /* BarrelSwitch */
> >  			map_key_clear(BTN_STYLUS);
> >  			break;
> > @@ -806,6 +818,20 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
> >  			map_key_clear(BTN_TOUCH);
> >  			break;
> >  
> > +		case 0x48: /* WIDTH */
> > +		case 0x49: /* HEIGHT */
> > +			map_abs_clear(ABS_TOOL_WIDTH);
> > +			break;
> > +
> > +		case 0x51: /* CONTACT ID */
> > +			goto ignore;
> > +
> > +		case 0x54: /* CONTACT COUNT */
> > +			goto ignore;
> > +
> > +		case 0x56: /* SCANTIME */
> > +			goto ignore;
> > +
> >  		case 0x46: /* TabletPick */
> >  		case 0x5a: /* SecondaryBarrelSwitch */
> >  			map_key_clear(BTN_STYLUS2);
> > diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> > index 65ea23be9677..a0b332518eaa 100644
> > --- a/drivers/hid/hid-multitouch.c
> > +++ b/drivers/hid/hid-multitouch.c
> > @@ -974,6 +974,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
> >  	    field->application != HID_DG_TOUCHPAD &&
> >  	    field->application != HID_GD_KEYBOARD &&
> >  	    field->application != HID_GD_SYSTEM_CONTROL &&
> > +	    field->application != HID_GD_SYSTEM_MULTIAXIS &&
> >  	    field->application != HID_CP_CONSUMER_CONTROL &&
> >  	    field->application != HID_GD_WIRELESS_RADIO_CTLS &&
> >  	    !(field->application == HID_VD_ASUS_CUSTOM_MEDIA_KEYS &&
> > @@ -1003,6 +1004,14 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
> >  		return 1;
> >  	}
> >  
> > +	/*
> > +	 * We do not want to export scantime on System MultiAxis
> > +	 * for now
> > +	 */
> > +	if (field->usage->hid == HID_DG_SCANTIME &&
> > +	    field->application == HID_GD_SYSTEM_MULTIAXIS)
> > +		return -1;
> > +
> >  	/*
> >  	 * some egalax touchscreens have "application == HID_DG_TOUCHSCREEN"
> >  	 * for the stylus.
> > @@ -1193,6 +1202,8 @@ static int mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
> >  			break;
> >  		case HID_GD_MOUSE:
> >  			suffix = "Mouse";
> > +		case HID_GD_SYSTEM_MULTIAXIS:
> > +			suffix = "MultiAxis";
> >  			break;
> >  		case HID_DG_STYLUS:
> >  			suffix = "Pen";
> > diff --git a/include/linux/hid.h b/include/linux/hid.h
> > index d491027a7c22..f93ebbe2f23d 100644
> > --- a/include/linux/hid.h
> > +++ b/include/linux/hid.h
> > @@ -189,6 +189,12 @@ struct hid_item {
> >   * http://www.usb.org/developers/hidpage/HUTRR40RadioHIDUsagesFinal.pdf
> >   */
> >  #define HID_GD_WIRELESS_RADIO_CTLS	0x0001000c
> > +/*
> > + * System Multi-Axis, see:
> > + * http://www.usb.org/developers/hidpage/HUTRR62_-_Generic_Desktop_CA_for_System_Multi-Axis_Controllers.txt
> > + */
> > +#define HID_GD_SYSTEM_MULTIAXIS	0x0001000e
> > +
> >  #define HID_GD_X		0x00010030
> >  #define HID_GD_Y		0x00010031
> >  #define HID_GD_Z		0x00010032
> > diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h
> > index 179891074b3c..f886499fdd4c 100644
> > --- a/include/uapi/linux/input-event-codes.h
> > +++ b/include/uapi/linux/input-event-codes.h
> > @@ -406,6 +406,7 @@
> >  #define BTN_TOOL_MOUSE		0x146
> >  #define BTN_TOOL_LENS		0x147
> >  #define BTN_TOOL_QUINTTAP	0x148	/* Five fingers on trackpad */
> > +#define BTN_TOOL_DIAL		0x149	/* System MultiAxis */
> >  #define BTN_TOUCH		0x14a
> >  #define BTN_STYLUS		0x14b
> >  #define BTN_STYLUS2		0x14c
> > -- 
> > 2.14.3
> > 

-- 
Dmitry

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