[PATCH 0/4] Stylus-on-touchscreen device support

This patchset adds support for stylus-on-touchscreen devices as found on
the OneMix 3 Pro and Dell Inspiron 15 7000 2-in-1 (7591), among others;
with it, they properly behave like a drawing tablet.

Patches 2 and 4 funxionally depend on patch 1.
Patch 4 needs patch 3 to apply.

The output of this patchset and the need for a kernel, rather than
userspace, patch was previously discussed here:
  https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/558#note_792834

Ahelenia Ziemiańska (4):
  HID: multitouch: require Finger field to mark Win8 reports as MT
  HID: multitouch: set Stylus suffix for Stylus-application devices, too
  HID: input: replace outdated HID numbers+comments with macros
  HID: input: work around Win8 stylus-on-touchscreen reporting

 drivers/hid/hid-input.c      | 47 +++++++++++++++++++++++++++++++++---
 drivers/hid/hid-multitouch.c | 18 ++++++++------
 2 files changed, 55 insertions(+), 10 deletions(-)

-- 
2.20.1

This effectively changes collection_is_mt from
  contact ID in report->field
to
  (device is Win8 => collection is finger) && contact ID in report->field

Some devices erroneously report Pen for fingers,
and Win8 stylus-on-touchscreen devices report contact ID,
but mark the accompanying touchscreen device's collection correctly

Signed-off-by: Ahelenia Ziemiańska <redacted>
---
 drivers/hid/hid-multitouch.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 8429ebe7097e..8580ace596c2 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c

@@ -604,9 +604,13 @@ static struct mt_report_data *mt_allocate_report_data(struct mt_device *td,
 		if (!(HID_MAIN_ITEM_VARIABLE & field->flags))
 			continue;
 
-		for (n = 0; n < field->report_count; n++) {
-			if (field->usage[n].hid == HID_DG_CONTACTID)
-				rdata->is_mt_collection = true;
+		if (field->logical == HID_DG_FINGER || td->hdev->group != HID_GROUP_MULTITOUCH_WIN_8) {
+			for (n = 0; n < field->report_count; n++) {
+				if (field->usage[n].hid == HID_DG_CONTACTID) {
+					rdata->is_mt_collection = true;
+					break;
+				}
+			}
 		}
 	}
 

-- 
2.20.1

This re-adds the suffix to Win8 stylus-on-touchscreen devices,
now that they aren't erroneously marked as MT

Signed-off-by: Ahelenia Ziemiańska <redacted>
---
 drivers/hid/hid-multitouch.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 8580ace596c2..e5a3704b9fe8 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c

@@ -1580,13 +1580,13 @@ static int mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
 		/* we do not set suffix = "Touchscreen" */
 		hi->input->name = hdev->name;
 		break;
-	case HID_DG_STYLUS:
-		/* force BTN_STYLUS to allow tablet matching in udev */
-		__set_bit(BTN_STYLUS, hi->input->keybit);
-		break;
 	case HID_VD_ASUS_CUSTOM_MEDIA_KEYS:
 		suffix = "Custom Media Keys";
 		break;
+	case HID_DG_STYLUS:
+		/* force BTN_STYLUS to allow tablet matching in udev */
+		__set_bit(BTN_STYLUS, hi->input->keybit);
+		fallthrough;
 	case HID_DG_PEN:
 		suffix = "Stylus";
 		break;

-- 
2.20.1

With this, these devices now behave as tablets as expected by userspace

Signed-off-by: Ahelenia Ziemiańska <redacted>
---
 drivers/hid/hid-input.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index a5ba92978473..b8813fc3e9d2 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c

@@ -1273,6 +1273,41 @@ 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.
+ */
+static void hidinput_fixup_win8_inrange(struct hid_device *hid, struct hid_field *field, __s32 *value)
+{
+	unsigned f, u;
+	struct hid_field *rfield;
+
+	if (!*value) {
+		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) {
+					*value = rfield->value[u];
+					return;
+				}
+			}
+		}
+	}
+}
+
 void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value)
 {
 	struct input_dev *input;

@@ -1306,7 +1341,13 @@ 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)
+			hidinput_fixup_win8_inrange(hid, field, &value);
+
 		if (value) {
 			input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1);
 			return;

-- 
2.20.1

These were untouched since 2.3.99-pre3, and the explanatory comment for
HID_DG_TIPPRESSURE is TipPressure on other places

Signed-off-by: Ahelenia Ziemiańska <redacted>
---
 drivers/hid/hid-input.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index f23027d2795b..a5ba92978473 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c

@@ -1301,12 +1301,12 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
 		return;
 	}
 
-	if (usage->hid == (HID_UP_DIGITIZER | 0x003c)) { /* Invert */
+	if (usage->hid == HID_DG_INVERT) {
 		*quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT);
 		return;
 	}
 
-	if (usage->hid == (HID_UP_DIGITIZER | 0x0032)) { /* InRange */
+	if (usage->hid == HID_DG_INRANGE) {
 		if (value) {
 			input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1);
 			return;

@@ -1316,7 +1316,7 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
 		return;
 	}
 
-	if (usage->hid == (HID_UP_DIGITIZER | 0x0030) && (*quirks & HID_QUIRK_NOTOUCH)) { /* Pressure */
+	if (usage->hid == HID_DG_TIPPRESSURE && (*quirks & HID_QUIRK_NOTOUCH)) {
 		int a = field->logical_minimum;
 		int b = field->logical_maximum;
 		input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3));

-- 
2.20.1

On Wed, 17 Feb 2021, наб wrote:

This patchset adds support for stylus-on-touchscreen devices as found on
the OneMix 3 Pro and Dell Inspiron 15 7000 2-in-1 (7591), among others;
with it, they properly behave like a drawing tablet.

Patches 2 and 4 funxionally depend on patch 1.
Patch 4 needs patch 3 to apply.

The output of this patchset and the need for a kernel, rather than
userspace, patch was previously discussed here:
  https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/558#note_792834

Ahelenia Ziemiańska (4):
  HID: multitouch: require Finger field to mark Win8 reports as MT
  HID: multitouch: set Stylus suffix for Stylus-application devices, too
  HID: input: replace outdated HID numbers+comments with macros
  HID: input: work around Win8 stylus-on-touchscreen reporting

 drivers/hid/hid-input.c      | 47 +++++++++++++++++++++++++++++++++---
 drivers/hid/hid-multitouch.c | 18 ++++++++------
 2 files changed, 55 insertions(+), 10 deletions(-)

Benjamin, this patchset looks good to me; do you have any objections on 
queuing it for 5.13?

Thanks,

-- 
Jiri Kosina
SUSE Labs

Hi Jiri,

On Mon, Mar 8, 2021 at 11:15 AM Jiri Kosina [off-list ref] wrote:

On Wed, 17 Feb 2021, наб wrote:

quoted

This patchset adds support for stylus-on-touchscreen devices as found on
the OneMix 3 Pro and Dell Inspiron 15 7000 2-in-1 (7591), among others;
with it, they properly behave like a drawing tablet.

Patches 2 and 4 funxionally depend on patch 1.
Patch 4 needs patch 3 to apply.

The output of this patchset and the need for a kernel, rather than
userspace, patch was previously discussed here:
  https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/558#note_792834

Ahelenia Ziemiańska (4):
  HID: multitouch: require Finger field to mark Win8 reports as MT
  HID: multitouch: set Stylus suffix for Stylus-application devices, too
  HID: input: replace outdated HID numbers+comments with macros
  HID: input: work around Win8 stylus-on-touchscreen reporting

 drivers/hid/hid-input.c      | 47 +++++++++++++++++++++++++++++++++---
 drivers/hid/hid-multitouch.c | 18 ++++++++------
 2 files changed, 55 insertions(+), 10 deletions(-)

Benjamin, this patchset looks good to me; do you have any objections on
queuing it for 5.13?

Please hold on this one. I am pretty sure this should break the test
suite but couldn't have the chance to get to it. Will pop this one up
in TODO list.

Cheers,
Benjamin

On Mon, Mar 08, 2021 at 11:21:56AM +0100, Benjamin Tissoires wrote:

On Mon, Mar 8, 2021 at 11:15 AM Jiri Kosina [off-list ref] wrote:

quoted

On Wed, 17 Feb 2021, наб wrote:

quoted

This patchset adds support for stylus-on-touchscreen devices as found on
the OneMix 3 Pro and Dell Inspiron 15 7000 2-in-1 (7591), among others;
with it, they properly behave like a drawing tablet.

Patches 2 and 4 funxionally depend on patch 1.
Patch 4 needs patch 3 to apply.

The output of this patchset and the need for a kernel, rather than
userspace, patch was previously discussed here:
  https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/558#note_792834

Ahelenia Ziemiańska (4):
  HID: multitouch: require Finger field to mark Win8 reports as MT
  HID: multitouch: set Stylus suffix for Stylus-application devices, too
  HID: input: replace outdated HID numbers+comments with macros
  HID: input: work around Win8 stylus-on-touchscreen reporting

 drivers/hid/hid-input.c      | 47 +++++++++++++++++++++++++++++++++---
 drivers/hid/hid-multitouch.c | 18 ++++++++------
 2 files changed, 55 insertions(+), 10 deletions(-)

Benjamin, this patchset looks good to me; do you have any objections on
queuing it for 5.13?

Please hold on this one. I am pretty sure this should break the test
suite but couldn't have the chance to get to it. Will pop this one up
in TODO list.

This also has minor behavioural problems regarding BTN_STYLUS reporting
that came out in testing, and I didn't have the time to dig through
and verify the logs from pre-v2 a tester sent back last week.

I hope to send v2 today/tomorrow, energy and time permitting.

Best,
наб