[PATCH 0/5] HID: multitouch: Add support for Touch Bars on x86 MacBook Pros

[PATCH 0/5] HID: multitouch: Add support for Touch Bars on x86 MacBook Pros

[Aditya Garg]

Hi all!

This patch series aims to improve the Touch Bar support for x86 Macs.

Recently, the hid-appletb-kbd and hid-appletb-bl drivers were upstreamed
into the Linux kernel [1]. They enabled the Touch Bar to display a
predefined set of media and function keys, exactly the same it does on
Windows Bootcamp.

Now we are about to get support added for the DRM mode of the Touch Bar
as well [2].

The DRM mode enables the Touch Bar to act as a second display,
just like macOS. So now you can add a widget, put a clock or anything
else on the Touch Bar as long as you can develop a daemon.

Now via these patches, in the DRM mode, we can use the Touch Bar as a
touch screen. The Touch Bar seems to be not compliant with the HID spec,
thus via these patches several tweaks have been done under the cover of
a single quirk, MT_QUIRK_APPLE_TOUCHBAR.

For the case of T2 Macs, apple-bce [4], the driver for the T2 Security
Chip is also needed for all the peripherals, including the Touch Bar
to work. It is still WIP, and will be subsequently sent later to the
appropriate tree. Till then, I'll suggest for get the driver from [3],
or more preferably, get Linux support from https://t2linux.org/.

Cheers
Aditya

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-6.15/apple
[2]: https://lore.kernel.org/dri-devel/72610225-c6e0-413a-a791-468635743fc2@suse.de/
[3]: https://github.com/t2linux/apple-bce-drv

Kerem Karabay (5):
  HID: multitouch: Get the contact ID from HID_DG_TRANSDUCER_INDEX
    fields in case of Apple Touch Bar
  HID: multitouch: support getting the tip state from HID_DG_TOUCH
    fields in Apple Touch Bar
  HID: multitouch: take cls->maxcontacts into account for Apple Touch
    Bar even without a HID_DG_CONTACTMAX field
  HID: multitouch: specify that Apple Touch Bar is direct
  HID: multitouch: add device ID for Apple Touch Bar

 drivers/hid/Kconfig          |  1 +
 drivers/hid/hid-multitouch.c | 70 +++++++++++++++++++++++++++++++-----
 2 files changed, 62 insertions(+), 9 deletions(-)

-- 
2.43.0

[PATCH 1/5] HID: multitouch: Get the contact ID from HID_DG_TRANSDUCER_INDEX fields in case of Apple Touch Bar

[Aditya Garg]

From: Kerem Karabay <kekrby@gmail.com>

In Apple Touch Bar, the contact ID is contained in fields with the
HID_DG_TRANSDUCER_INDEX usage rather than HID_DG_CONTACTID, thus differing
from the HID spec. Add a quirk for the same.

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Co-developed-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
---
 drivers/hid/hid-multitouch.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index e50887a6d..6e7f34a47 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -73,6 +73,7 @@ MODULE_LICENSE("GPL");
 #define MT_QUIRK_FORCE_MULTI_INPUT	BIT(20)
 #define MT_QUIRK_DISABLE_WAKEUP		BIT(21)
 #define MT_QUIRK_ORIENTATION_INVERT	BIT(22)
+#define MT_QUIRK_APPLE_TOUCHBAR		BIT(23)
 
 #define MT_INPUTMODE_TOUCHSCREEN	0x02
 #define MT_INPUTMODE_TOUCHPAD		0x03
@@ -625,6 +626,7 @@ static struct mt_application *mt_find_application(struct mt_device *td,
 static struct mt_report_data *mt_allocate_report_data(struct mt_device *td,
 						      struct hid_report *report)
 {
+	struct mt_class *cls = &td->mtclass;
 	struct mt_report_data *rdata;
 	struct hid_field *field;
 	int r, n;
@@ -649,7 +651,11 @@ static struct mt_report_data *mt_allocate_report_data(struct mt_device *td,
 
 		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) {
+				unsigned int hid = field->usage[n].hid;
+
+				if (hid == HID_DG_CONTACTID ||
+				   (cls->quirks & MT_QUIRK_APPLE_TOUCHBAR &&
+				   hid == HID_DG_TRANSDUCER_INDEX)) {
 					rdata->is_mt_collection = true;
 					break;
 				}
@@ -827,6 +833,14 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 						     EV_KEY, BTN_TOUCH);
 			MT_STORE_FIELD(tip_state);
 			return 1;
+		case HID_DG_TRANSDUCER_INDEX:
+			/*
+			 * Contact ID in case of Apple Touch Bars is contained
+			 * in fields with HID_DG_TRANSDUCER_INDEX usage.
+			 */
+			if (!(cls->quirks & MT_QUIRK_APPLE_TOUCHBAR))
+				return 0;
+			fallthrough;
 		case HID_DG_CONTACTID:
 			MT_STORE_FIELD(contactid);
 			app->touches_by_report++;
-- 
2.43.0

[PATCH 2/5] HID: multitouch: support getting the tip state from HID_DG_TOUCH fields in Apple Touch Bar

[Aditya Garg]

From: Kerem Karabay <kekrby@gmail.com>

In Apple Touch Bar, the tip state is contained in fields with the
HID_DG_TOUCH usage. This feature is gated by a quirk in order to
prevent breaking other devices, see commit c2ef8f21ea8f
("HID: multitouch: add support for trackpads").

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Co-developed-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
---
 drivers/hid/hid-multitouch.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 6e7f34a47..70fdd8cf9 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -827,6 +827,17 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 
 			MT_STORE_FIELD(confidence_state);
 			return 1;
+		case HID_DG_TOUCH:
+			/*
+			 * Legacy devices use TIPSWITCH and not TOUCH.
+			 * One special case here is of the Apple Touch Bars.
+			 * In these devices, the tip state is contained in
+			 * fields with the HID_DG_TOUCH usage.
+			 * Let's just ignore this field for other devices.
+			 */
+			if (!(cls->quirks & MT_QUIRK_APPLE_TOUCHBAR))
+				return -1;
+			fallthrough;
 		case HID_DG_TIPSWITCH:
 			if (field->application != HID_GD_SYSTEM_MULTIAXIS)
 				input_set_capability(hi->input,
@@ -897,10 +908,6 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 		case HID_DG_CONTACTMAX:
 			/* contact max are global to the report */
 			return -1;
-		case HID_DG_TOUCH:
-			/* Legacy devices use TIPSWITCH and not TOUCH.
-			 * Let's just ignore this field. */
-			return -1;
 		}
 		/* let hid-input decide for the others */
 		return 0;
-- 
2.43.0

[PATCH 3/5] HID: multitouch: take cls->maxcontacts into account for Apple Touch Bar even without a HID_DG_CONTACTMAX field

[Aditya Garg]

From: Kerem Karabay <kekrby@gmail.com>

In Apple Touch Bar, the HID_DG_CONTACTMAX is not present, but the maximum
contact count is still greater than the default. Add quirks for the same.

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Co-developed-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
---
 drivers/hid/hid-multitouch.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 70fdd8cf9..f7fe6aab8 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -1335,6 +1335,13 @@ static int mt_touch_input_configured(struct hid_device *hdev,
 	struct input_dev *input = hi->input;
 	int ret;
 
+	/*
+	 * HID_DG_CONTACTMAX field is not present on Apple Touch Bars,
+	 * but the maximum contact count is greater than the default.
+	 */
+	if (cls->quirks & MT_QUIRK_APPLE_TOUCHBAR && cls->maxcontacts)
+		td->maxcontacts = cls->maxcontacts;
+
 	if (!td->maxcontacts)
 		td->maxcontacts = MT_DEFAULT_MAXCONTACT;
 
-- 
2.43.0

[PATCH 4/5] HID: multitouch: specify that Apple Touch Bar is direct

[Aditya Garg]

From: Kerem Karabay <kekrby@gmail.com>

Currently the driver determines the device type based on the
application, but this value is not reliable on Apple Touch Bar, where
the application is HID_DG_TOUCHPAD even though this device is direct,
so add a quirk for the same.

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Co-developed-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
---
 drivers/hid/hid-multitouch.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index f7fe6aab8..66e33a482 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -1349,6 +1349,13 @@ static int mt_touch_input_configured(struct hid_device *hdev,
 	if (td->serial_maybe)
 		mt_post_parse_default_settings(td, app);
 
+	/*
+	 * The application for Apple Touch Bars is HID_DG_TOUCHPAD,
+	 * but these devices are direct.
+	 */
+	if (cls->quirks & MT_QUIRK_APPLE_TOUCHBAR)
+		app->mt_flags |= INPUT_MT_DIRECT;
+
 	if (cls->is_indirect)
 		app->mt_flags |= INPUT_MT_POINTER;
 
-- 
2.43.0

[PATCH 5/5] HID: multitouch: add device ID for Apple Touch Bar

[Aditya Garg]

From: Kerem Karabay <kekrby@gmail.com>

This patch adds the device ID of Apple Touch Bar found on x86 MacBook Pros
to the hid-multitouch driver.

Note that this is device ID is for T2 Macs. Testing on T1 Macs would be
appreciated.

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Co-developed-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
---
 drivers/hid/Kconfig          |  1 +
 drivers/hid/hid-multitouch.c | 25 +++++++++++++++++++++----
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index dfc245867..727a2ed0d 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -743,6 +743,7 @@ config HID_MULTITOUCH
 	  Say Y here if you have one of the following devices:
 	  - 3M PCT touch screens
 	  - ActionStar dual touch panels
+	  - Apple Touch Bar on x86 MacBook Pros
 	  - Atmel panels
 	  - Cando dual touch panels
 	  - Chunghwa panels
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 66e33a482..078ceef62 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -221,6 +221,7 @@ static void mt_post_parse(struct mt_device *td, struct mt_application *app);
 #define MT_CLS_GOOGLE				0x0111
 #define MT_CLS_RAZER_BLADE_STEALTH		0x0112
 #define MT_CLS_SMART_TECH			0x0113
+#define MT_CLS_APPLE_TOUCHBAR			0x0114
 #define MT_CLS_SIS				0x0457
 
 #define MT_DEFAULT_MAXCONTACT	10
@@ -406,6 +407,12 @@ static const struct mt_class mt_classes[] = {
 			MT_QUIRK_CONTACT_CNT_ACCURATE |
 			MT_QUIRK_SEPARATE_APP_REPORT,
 	},
+	{ .name = MT_CLS_APPLE_TOUCHBAR,
+		.quirks = MT_QUIRK_HOVERING |
+			MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE |
+			MT_QUIRK_APPLE_TOUCHBAR,
+		.maxcontacts = 11,
+	},
 	{ .name = MT_CLS_SIS,
 		.quirks = MT_QUIRK_NOT_SEEN_MEANS_UP |
 			MT_QUIRK_ALWAYS_VALID |
@@ -1807,6 +1814,15 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 		}
 	}
 
+	ret = hid_parse(hdev);
+	if (ret != 0)
+		return ret;
+
+	if (mtclass->name == MT_CLS_APPLE_TOUCHBAR &&
+	    !hid_find_field(hdev, HID_INPUT_REPORT,
+			    HID_DG_TOUCHPAD, HID_DG_TRANSDUCER_INDEX))
+		return -ENODEV;
+
 	td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);
 	if (!td) {
 		dev_err(&hdev->dev, "cannot allocate multitouch data\n");
@@ -1854,10 +1870,6 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	timer_setup(&td->release_timer, mt_expired_timeout, 0);
 
-	ret = hid_parse(hdev);
-	if (ret != 0)
-		return ret;
-
 	if (mtclass->quirks & MT_QUIRK_FIX_CONST_CONTACT_ID)
 		mt_fix_const_fields(hdev, HID_DG_CONTACTID);
 
@@ -2339,6 +2351,11 @@ static const struct hid_device_id mt_devices[] = {
 		MT_USB_DEVICE(USB_VENDOR_ID_XIROKU,
 			USB_DEVICE_ID_XIROKU_CSR2) },
 
+	/* Apple Touch Bar */
+	{ .driver_data = MT_CLS_APPLE_TOUCHBAR,
+		HID_USB_DEVICE(USB_VENDOR_ID_APPLE,
+			USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
+
 	/* Google MT devices */
 	{ .driver_data = MT_CLS_GOOGLE,
 		HID_DEVICE(HID_BUS_ANY, HID_GROUP_ANY, USB_VENDOR_ID_GOOGLE,
-- 
2.43.0