With this, these devices now behave as tablets as expected by userspace The search in hidinput_is_win8_touching() terminates at f=0, u=0 on Goodix screens (27C6:0111, 27C6:0113), but I expect it to have negligible impact on devices that don't have TipSwitch as the first report as well
Signed-off-by: Ahelenia Ziemiańska <[email protected]> --- Notes: changes in v2: * hidinput_fixup_win8_inrange() became hidinput_is_win8_touching() * BarrelSwitch now anded with TipSwitch drivers/hid/hid-input.c | 48 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index a5ba92978473..aee1f1283c1d 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -1273,6 +1273,42 @@ static void hidinput_handle_scroll(struct hid_usage *usage, input_event(input, EV_REL, usage->code, hi_res); } +/* + * Win8 tablet stylus devices send, in order: + * HID_DG_TIPSWITCH (BTN_TOUCH) + * HID_DG_INVERT (BTN_TOOL_RUBBER) + * HID_DG_ERASER (BTN_TOUCH) + * HID_DG_INRANGE (BTN_TOOL_PEN) + * + * For each of these states: + * hover : INRANGE + * touching : TIPSWITCH + * hover+2 : INVERT INRANGE + * touching+2: ERASER INRANGE + * + * Which means we'd send BTN_TOUCH=0 + BTN_TOOL_PEN=1 on proximity, + * then BTN_TOUCH=1 and BTN_TOOL_PEN=0 in consecutive groups when touched, + * indicating the stylus leaving the screen as soon as the two meet. + * + * Additionally, HID_DG_BARRELSWITCH corresponds directly to the button, + * regardless of the tip switch, making it borderline impossible to use precisely. + */ +static bool hidinput_is_win8_touching(struct hid_device *hid, struct hid_field *field) +{ + unsigned f, u; + struct hid_field *rfield; + + for (f = 0; f < field->report->maxfield; ++f) { + rfield = field->report->field[f]; + for (u = 0; u < rfield->maxusage; ++u) { + if (rfield->usage[u].hid == HID_DG_TIPSWITCH) + return rfield->value[u]; + } + } + + return false; +} + void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value) { struct input_dev *input; @@ -1306,7 +1342,13 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct return; } + if (usage->hid == HID_DG_ERASER && value) + *quirks |= HID_QUIRK_INVERT; + if (usage->hid == HID_DG_INRANGE) { + if (hid->group == HID_GROUP_MULTITOUCH_WIN_8) + value = value || hidinput_is_win8_touching(hid, field); + if (value) { input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1); return; @@ -1322,6 +1364,12 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3)); } + if (usage->hid == HID_DG_BARRELSWITCH && hid->group == HID_GROUP_MULTITOUCH_WIN_8) { + value = value && hidinput_is_win8_touching(hid, field); + input_event(input, usage->type, usage->code, value); + return; + } + if (usage->hid == (HID_UP_PID | 0x83UL)) { /* Simultaneous Effects Max */ dbg_hid("Maximum Effects - %d\n",value); return; -- 2.20.1
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