[v5,2/10] HID: hid-appletb-kbd: add driver for the keyboard mode

Commit Message

Aditya Garg Aug. 17, 2024, 11:46 a.m. UTC

From: Kerem Karabay <[e-mail]>

The Touch Bars found on x86 Macs support two USB configurations: one
where the device presents itself as a HID keyboard and can display
predefined sets of keys, and one where the operating system has full
control over what is displayed. This commit adds a driver for the
display functionality of the first configuration.

Note that currently only T2 Macs are supported.

This driver is based on previous work done by Ronald Tschalär
<[e-mail]>.

Signed-off-by: Kerem Karabay <[e-mail]>
Co-developed-by: Aditya Garg <[e-mail]>
Signed-off-by: Aditya Garg <[e-mail]>
---
 .../ABI/testing/sysfs-driver-hid-appletb-kbd  |  13 +
 drivers/hid/Kconfig                           |  11 +
 drivers/hid/Makefile                          |   1 +
 drivers/hid/hid-appletb-kbd.c                 | 304 ++++++++++++++++++
 drivers/hid/hid-quirks.c                      |   4 +-
 5 files changed, 332 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd
 create mode 100644 drivers/hid/hid-appletb-kbd.c

Comments

Benjamin Tissoires Sept. 27, 2024, 3:39 p.m. UTC | #1

On Aug 17 2024, Aditya Garg wrote:
> From: Kerem Karabay <[e-mail]>
> 
> The Touch Bars found on x86 Macs support two USB configurations: one
> where the device presents itself as a HID keyboard and can display
> predefined sets of keys, and one where the operating system has full
> control over what is displayed. This commit adds a driver for the
> display functionality of the first configuration.
> 
> Note that currently only T2 Macs are supported.
> 
> This driver is based on previous work done by Ronald Tschalär
> <[e-mail]>.
> 
> Signed-off-by: Kerem Karabay <[e-mail]>
> Co-developed-by: Aditya Garg <[e-mail]>
> Signed-off-by: Aditya Garg <[e-mail]>
> ---
>  .../ABI/testing/sysfs-driver-hid-appletb-kbd  |  13 +
>  drivers/hid/Kconfig                           |  11 +
>  drivers/hid/Makefile                          |   1 +
>  drivers/hid/hid-appletb-kbd.c                 | 304 ++++++++++++++++++
>  drivers/hid/hid-quirks.c                      |   4 +-
>  5 files changed, 332 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd
>  create mode 100644 drivers/hid/hid-appletb-kbd.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd b/Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd
> new file mode 100644
> index 000000000..2a19584d0
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd
> @@ -0,0 +1,13 @@
> +What:		/sys/bus/hid/drivers/hid-appletb-kbd/<dev>/mode
> +Date:		September, 2023
> +KernelVersion:	6.5
> +Contact:	[e-mail]
> +Description:
> +		The set of keys displayed on the Touch Bar.
> +		Valid values are:
> +		== =================
> +		0  Escape key only
> +		1  Function keys
> +		2  Media/brightness keys
> +		3  None
> +		== =================
> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> index 4988c1fb2..72b665eda 100644
> --- a/drivers/hid/Kconfig
> +++ b/drivers/hid/Kconfig
> @@ -158,6 +158,17 @@ config HID_APPLETB_BL
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called hid-appletb-bl.
>  
> +config HID_APPLETB_KBD
> +	tristate "Apple Touch Bar Keyboard Mode"
> +	depends on USB_HID
> +	help
> +	  Say Y here if you want support for the keyboard mode (escape,
> +	  function, media and brightness keys) of Touch Bars on x86 MacBook
> +	  Pros.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called hid-appletb-kbd.
> +
>  config HID_ASUS
>  	tristate "Asus"
>  	depends on USB_HID
> diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
> index 1d825a474..d903c9a26 100644
> --- a/drivers/hid/Makefile
> +++ b/drivers/hid/Makefile
> @@ -30,6 +30,7 @@ obj-$(CONFIG_HID_ACRUX)		+= hid-axff.o
>  obj-$(CONFIG_HID_APPLE)		+= hid-apple.o
>  obj-$(CONFIG_HID_APPLEIR)	+= hid-appleir.o
>  obj-$(CONFIG_HID_APPLETB_BL)	+= hid-appletb-bl.o
> +obj-$(CONFIG_HID_APPLETB_KBD)	+= hid-appletb-kbd.o
>  obj-$(CONFIG_HID_CREATIVE_SB0540)	+= hid-creative-sb0540.o
>  obj-$(CONFIG_HID_ASUS)		+= hid-asus.o
>  obj-$(CONFIG_HID_AUREAL)	+= hid-aureal.o
> diff --git a/drivers/hid/hid-appletb-kbd.c b/drivers/hid/hid-appletb-kbd.c
> new file mode 100644
> index 000000000..ecac68fc7
> --- /dev/null
> +++ b/drivers/hid/hid-appletb-kbd.c
> @@ -0,0 +1,304 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Apple Touch Bar Keyboard Mode Driver
> + *
> + * Copyright (c) 2017-2018 Ronald Tschalär
> + * Copyright (c) 2022-2023 Kerem Karabay <[e-mail]>
> + * Copyright (c) 2024 Aditya Garg <[e-mail]>
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/hid.h>
> +#include <linux/usb.h>
> +#include <linux/input.h>
> +#include <linux/sysfs.h>
> +#include <linux/bitops.h>
> +#include <linux/module.h>
> +#include <linux/string.h>
> +#include <linux/input/sparse-keymap.h>
> +
> +#include "hid-ids.h"
> +
> +#define APPLETB_KBD_MODE_ESC	0
> +#define APPLETB_KBD_MODE_FN	1
> +#define APPLETB_KBD_MODE_SPCL	2
> +#define APPLETB_KBD_MODE_OFF	3
> +#define APPLETB_KBD_MODE_MAX	APPLETB_KBD_MODE_OFF
> +
> +#define HID_USAGE_MODE		0x00ff0004
> +
> +static int appletb_tb_def_mode = APPLETB_KBD_MODE_SPCL;
> +module_param_named(mode, appletb_tb_def_mode, int, 0444);
> +MODULE_PARM_DESC(mode, "Default touchbar mode:\n"
> +			 "    0 - escape key only\n"
> +			 "    1 - function-keys\n"
> +			 "    [2] - special keys");
> +
> +struct appletb_kbd {
> +	struct hid_field *mode_field;
> +
> +	u8 saved_mode;
> +	u8 current_mode;
> +};
> +
> +static const struct key_entry appletb_kbd_keymap[] = {
> +	{ KE_KEY, KEY_ESC, { KEY_ESC } },
> +	{ KE_KEY, KEY_F1,  { KEY_BRIGHTNESSDOWN } },
> +	{ KE_KEY, KEY_F2,  { KEY_BRIGHTNESSUP } },
> +	{ KE_KEY, KEY_F3,  { KEY_RESERVED } },
> +	{ KE_KEY, KEY_F4,  { KEY_RESERVED } },
> +	{ KE_KEY, KEY_F5,  { KEY_KBDILLUMDOWN } },
> +	{ KE_KEY, KEY_F6,  { KEY_KBDILLUMUP } },
> +	{ KE_KEY, KEY_F7,  { KEY_PREVIOUSSONG } },
> +	{ KE_KEY, KEY_F8,  { KEY_PLAYPAUSE } },
> +	{ KE_KEY, KEY_F9,  { KEY_NEXTSONG } },
> +	{ KE_KEY, KEY_F10, { KEY_MUTE } },
> +	{ KE_KEY, KEY_F11, { KEY_VOLUMEDOWN } },
> +	{ KE_KEY, KEY_F12, { KEY_VOLUMEUP } },
> +	{ KE_END, 0 }
> +};
> +
> +static int appletb_kbd_set_mode(struct appletb_kbd *kbd, u8 mode)
> +{
> +	struct hid_report *report = kbd->mode_field->report;
> +	struct hid_device *hdev = report->device;
> +	int ret;
> +
> +	ret = hid_hw_power(hdev, PM_HINT_FULLON);
> +	if (ret) {
> +		hid_err(hdev, "Device didn't resume (%pe)\n", ERR_PTR(ret));
> +		return ret;
> +	}
> +
> +	ret = hid_set_field(kbd->mode_field, 0, mode);
> +	if (ret) {
> +		hid_err(hdev, "Failed to set mode field to %u (%pe)\n", mode, ERR_PTR(ret));
> +		goto power_normal;
> +	}
> +
> +	hid_hw_request(hdev, report, HID_REQ_SET_REPORT);
> +
> +	kbd->current_mode = mode;
> +
> +power_normal:
> +	hid_hw_power(hdev, PM_HINT_NORMAL);
> +
> +	return ret;
> +}
> +
> +static ssize_t mode_show(struct device *dev,
> +			 struct device_attribute *attr, char *buf)
> +{
> +	struct appletb_kbd *kbd = dev_get_drvdata(dev);
> +
> +	return sysfs_emit(buf, "%d\n", kbd->current_mode);
> +}
> +
> +static ssize_t mode_store(struct device *dev,
> +			  struct device_attribute *attr,
> +			  const char *buf, size_t size)
> +{
> +	struct appletb_kbd *kbd = dev_get_drvdata(dev);
> +	u8 mode;
> +	int ret;
> +
> +	ret = kstrtou8(buf, 0, &mode);
> +	if (ret)
> +		return ret;
> +
> +	if (mode > APPLETB_KBD_MODE_MAX)
> +		return -EINVAL;
> +
> +	ret = appletb_kbd_set_mode(kbd, mode);
> +
> +	return ret < 0 ? ret : size;
> +}
> +static DEVICE_ATTR_RW(mode);
> +
> +struct attribute *appletb_kbd_attrs[] = {
> +	&dev_attr_mode.attr,
> +	NULL
> +};
> +ATTRIBUTE_GROUPS(appletb_kbd);
> +
> +static int appletb_tb_key_to_slot(unsigned int code)
> +{
> +	switch (code) {
> +	case KEY_ESC:
> +		return 0;
> +	case KEY_F1 ... KEY_F10:
> +		return code - KEY_F1 + 1;
> +	case KEY_F11 ... KEY_F12:
> +		return code - KEY_F11 + 11;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int appletb_kbd_hid_event(struct hid_device *hdev, struct hid_field *field,
> +				      struct hid_usage *usage, __s32 value)
> +{
> +	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
> +	struct key_entry *translation;
> +	struct input_dev *input;
> +	int slot;
> +
> +	if ((usage->hid & HID_USAGE_PAGE) != HID_UP_KEYBOARD || usage->type != EV_KEY)
> +		return 0;
> +
> +	input = field->hidinput->input;
> +
> +	/*
> +	 * Skip non-touch-bar keys.
> +	 *
> +	 * Either the touch bar itself or usbhid generate a slew of key-down
> +	 * events for all the meta keys. None of which we're at all interested
> +	 * in.
> +	 */
> +	slot = appletb_tb_key_to_slot(usage->code);
> +	if (slot < 0)
> +		return 0;
> +
> +	translation = sparse_keymap_entry_from_scancode(input, usage->code);

You are missing a Kconfig depends or select here because when enabling
this module, we can get

ERROR: modpost: "sparse_keymap_setup" [drivers/hid/hid-appletb-kbd.ko] undefined!
ERROR: modpost: "sparse_keymap_entry_from_scancode" [drivers/hid/hid-appletb-kbd.ko] undefined!

FWIW, I tried "depend on INPUT_SPARSEKMAP" and "select
INPUT_SPARSEKMAP", but in both cases the error was there, so I suspect
there is one extra config to select (could be my script but if I can
enter this state, I believe others will get into it as well).

Cheers,
Benjamin

> +
> +	if (translation && kbd->current_mode == APPLETB_KBD_MODE_SPCL) {
> +		input_event(input, usage->type, translation->keycode, value);
> +
> +		return 1;
> +	}
> +
> +	return kbd->current_mode == APPLETB_KBD_MODE_OFF;
> +}
> +
> +static int appletb_kbd_input_configured(struct hid_device *hdev, struct hid_input *hidinput)
> +{
> +	int idx;
> +	struct input_dev *input = hidinput->input;
> +
> +	/*
> +	 * Clear various input capabilities that are blindly set by the hid
> +	 * driver (usbkbd.c)
> +	 */
> +	memset(input->evbit, 0, sizeof(input->evbit));
> +	memset(input->keybit, 0, sizeof(input->keybit));
> +	memset(input->ledbit, 0, sizeof(input->ledbit));
> +
> +	__set_bit(EV_REP, input->evbit);
> +
> +	sparse_keymap_setup(input, appletb_kbd_keymap, NULL);
> +
> +	for (idx = 0; appletb_kbd_keymap[idx].type != KE_END; idx++) {
> +		input_set_capability(input, EV_KEY, appletb_kbd_keymap[idx].code);
> +	}
> +
> +	return 0;
> +}
> +
> +static int appletb_kbd_probe(struct hid_device *hdev, const struct hid_device_id *id)
> +{
> +	struct appletb_kbd *kbd;
> +	struct device *dev = &hdev->dev;
> +	struct hid_field *mode_field;
> +	int ret;
> +
> +	ret = hid_parse(hdev);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "HID parse failed\n");
> +
> +	mode_field = hid_find_field(hdev, HID_OUTPUT_REPORT,
> +				    HID_GD_KEYBOARD, HID_USAGE_MODE);
> +	if (!mode_field)
> +		return -ENODEV;
> +
> +	kbd = devm_kzalloc(dev, sizeof(*kbd), GFP_KERNEL);
> +	if (!kbd)
> +		return -ENOMEM;
> +
> +	kbd->mode_field = mode_field;
> +
> +	ret = hid_hw_start(hdev, HID_CONNECT_HIDINPUT);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "HID hw start failed\n");
> +
> +	ret = hid_hw_open(hdev);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "HID hw open failed\n");
> +		goto stop_hw;
> +	}
> +
> +	ret = appletb_kbd_set_mode(kbd, appletb_tb_def_mode);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "Failed to set touchbar mode\n");
> +		goto close_hw;
> +	}
> +
> +	hid_set_drvdata(hdev, kbd);
> +
> +	return 0;
> +
> +close_hw:
> +	hid_hw_close(hdev);
> +stop_hw:
> +	hid_hw_stop(hdev);
> +	return ret;
> +}
> +
> +static void appletb_kbd_remove(struct hid_device *hdev)
> +{
> +	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
> +
> +	appletb_kbd_set_mode(kbd, APPLETB_KBD_MODE_OFF);
> +
> +	hid_hw_close(hdev);
> +	hid_hw_stop(hdev);
> +}
> +
> +#ifdef CONFIG_PM
> +static int appletb_kbd_suspend(struct hid_device *hdev, pm_message_t msg)
> +{
> +	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
> +
> +	kbd->saved_mode = kbd->current_mode;
> +	appletb_kbd_set_mode(kbd, APPLETB_KBD_MODE_OFF);
> +
> +	return 0;
> +}
> +
> +static int appletb_kbd_reset_resume(struct hid_device *hdev)
> +{
> +	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
> +
> +	appletb_kbd_set_mode(kbd, kbd->saved_mode);
> +
> +	return 0;
> +}
> +#endif
> +
> +static const struct hid_device_id appletb_kbd_hid_ids[] = {
> +	/* MacBook Pro's 2018, 2019, with T2 chip: iBridge Display */
> +	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(hid, appletb_kbd_hid_ids);
> +
> +static struct hid_driver appletb_kbd_hid_driver = {
> +	.name = "hid-appletb-kbd",
> +	.id_table = appletb_kbd_hid_ids,
> +	.probe = appletb_kbd_probe,
> +	.remove = appletb_kbd_remove,
> +	.event = appletb_kbd_hid_event,
> +	.input_configured = appletb_kbd_input_configured,
> +#ifdef CONFIG_PM
> +	.suspend = appletb_kbd_suspend,
> +	.reset_resume = appletb_kbd_reset_resume,
> +#endif
> +	.driver.dev_groups = appletb_kbd_groups,
> +};
> +module_hid_driver(appletb_kbd_hid_driver);
> +
> +MODULE_AUTHOR("Ronald Tschalär");
> +MODULE_AUTHOR("Kerem Karabay <[e-mail]>");
> +MODULE_DESCRIPTION("MacBookPro Touch Bar Keyboard Mode Driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c
> index 818d41a35..7c576d654 100644
> --- a/drivers/hid/hid-quirks.c
> +++ b/drivers/hid/hid-quirks.c
> @@ -328,7 +328,6 @@ static const struct hid_device_id hid_have_special_driver[] = {
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_GEYSER1_TP_ONLY) },
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_2021) },
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_FINGERPRINT_2021) },
> -	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
>  #endif
>  #if IS_ENABLED(CONFIG_HID_APPLEIR)
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL) },
> @@ -340,6 +339,9 @@ static const struct hid_device_id hid_have_special_driver[] = {
>  #if IS_ENABLED(CONFIG_HID_APPLETB_BL)
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT) },
>  #endif
> +#if IS_ENABLED(CONFIG_HID_APPLETB_KBD)
> +	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
> +#endif
>  #if IS_ENABLED(CONFIG_HID_ASUS)
>  	{ HID_I2C_DEVICE(USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_I2C_KEYBOARD) },
>  	{ HID_I2C_DEVICE(USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_I2C_TOUCHPAD) },
> -- 
> 2.43.0
>

Aditya Garg Sept. 28, 2024, 5:56 a.m. UTC | #2

> On 27 Sep 2024, at 9:09 PM, Benjamin Tissoires <[e-mail]> wrote:
> 
> On Aug 17 2024, Aditya Garg wrote:
>> From: Kerem Karabay <[e-mail]>
>> 
>> The Touch Bars found on x86 Macs support two USB configurations: one
>> where the device presents itself as a HID keyboard and can display
>> predefined sets of keys, and one where the operating system has full
>> control over what is displayed. This commit adds a driver for the
>> display functionality of the first configuration.
>> 
>> Note that currently only T2 Macs are supported.
>> 
>> This driver is based on previous work done by Ronald Tschalär
>> <[e-mail]>.
>> 
>> Signed-off-by: Kerem Karabay <[e-mail]>
>> Co-developed-by: Aditya Garg <[e-mail]>
>> Signed-off-by: Aditya Garg <[e-mail]>
>> ---
>> .../ABI/testing/sysfs-driver-hid-appletb-kbd  |  13 +
>> drivers/hid/Kconfig                           |  11 +
>> drivers/hid/Makefile                          |   1 +
>> drivers/hid/hid-appletb-kbd.c                 | 304 ++++++++++++++++++
>> drivers/hid/hid-quirks.c                      |   4 +-
>> 5 files changed, 332 insertions(+), 1 deletion(-)
>> create mode 100644 Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd
>> create mode 100644 drivers/hid/hid-appletb-kbd.c
>> 
>> diff --git a/Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd b/Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd
>> new file mode 100644
>> index 000000000..2a19584d0
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd
>> @@ -0,0 +1,13 @@
>> +What:        /sys/bus/hid/drivers/hid-appletb-kbd/<dev>/mode
>> +Date:        September, 2023
>> +KernelVersion:    6.5
>> +Contact:    [e-mail]
>> +Description:
>> +        The set of keys displayed on the Touch Bar.
>> +        Valid values are:
>> +        == =================
>> +        0  Escape key only
>> +        1  Function keys
>> +        2  Media/brightness keys
>> +        3  None
>> +        == =================
>> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
>> index 4988c1fb2..72b665eda 100644
>> --- a/drivers/hid/Kconfig
>> +++ b/drivers/hid/Kconfig
>> @@ -158,6 +158,17 @@ config HID_APPLETB_BL
>>      To compile this driver as a module, choose M here: the
>>      module will be called hid-appletb-bl.
>> 
>> +config HID_APPLETB_KBD
>> +    tristate "Apple Touch Bar Keyboard Mode"
>> +    depends on USB_HID
>> +    help
>> +      Say Y here if you want support for the keyboard mode (escape,
>> +      function, media and brightness keys) of Touch Bars on x86 MacBook
>> +      Pros.
>> +
>> +      To compile this driver as a module, choose M here: the
>> +      module will be called hid-appletb-kbd.
>> +
>> config HID_ASUS
>>    tristate "Asus"
>>    depends on USB_HID
>> diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
>> index 1d825a474..d903c9a26 100644
>> --- a/drivers/hid/Makefile
>> +++ b/drivers/hid/Makefile
>> @@ -30,6 +30,7 @@ obj-$(CONFIG_HID_ACRUX)        += hid-axff.o
>> obj-$(CONFIG_HID_APPLE)        += hid-apple.o
>> obj-$(CONFIG_HID_APPLEIR)    += hid-appleir.o
>> obj-$(CONFIG_HID_APPLETB_BL)    += hid-appletb-bl.o
>> +obj-$(CONFIG_HID_APPLETB_KBD)    += hid-appletb-kbd.o
>> obj-$(CONFIG_HID_CREATIVE_SB0540)    += hid-creative-sb0540.o
>> obj-$(CONFIG_HID_ASUS)        += hid-asus.o
>> obj-$(CONFIG_HID_AUREAL)    += hid-aureal.o
>> diff --git a/drivers/hid/hid-appletb-kbd.c b/drivers/hid/hid-appletb-kbd.c
>> new file mode 100644
>> index 000000000..ecac68fc7
>> --- /dev/null
>> +++ b/drivers/hid/hid-appletb-kbd.c
>> @@ -0,0 +1,304 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Apple Touch Bar Keyboard Mode Driver
>> + *
>> + * Copyright (c) 2017-2018 Ronald Tschalär
>> + * Copyright (c) 2022-2023 Kerem Karabay <[e-mail]>
>> + * Copyright (c) 2024 Aditya Garg <[e-mail]>
>> + */
>> +
>> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> +
>> +#include <linux/hid.h>
>> +#include <linux/usb.h>
>> +#include <linux/input.h>
>> +#include <linux/sysfs.h>
>> +#include <linux/bitops.h>
>> +#include <linux/module.h>
>> +#include <linux/string.h>
>> +#include <linux/input/sparse-keymap.h>
>> +
>> +#include "hid-ids.h"
>> +
>> +#define APPLETB_KBD_MODE_ESC    0
>> +#define APPLETB_KBD_MODE_FN    1
>> +#define APPLETB_KBD_MODE_SPCL    2
>> +#define APPLETB_KBD_MODE_OFF    3
>> +#define APPLETB_KBD_MODE_MAX    APPLETB_KBD_MODE_OFF
>> +
>> +#define HID_USAGE_MODE        0x00ff0004
>> +
>> +static int appletb_tb_def_mode = APPLETB_KBD_MODE_SPCL;
>> +module_param_named(mode, appletb_tb_def_mode, int, 0444);
>> +MODULE_PARM_DESC(mode, "Default touchbar mode:\n"
>> +             "    0 - escape key only\n"
>> +             "    1 - function-keys\n"
>> +             "    [2] - special keys");
>> +
>> +struct appletb_kbd {
>> +    struct hid_field *mode_field;
>> +
>> +    u8 saved_mode;
>> +    u8 current_mode;
>> +};
>> +
>> +static const struct key_entry appletb_kbd_keymap[] = {
>> +    { KE_KEY, KEY_ESC, { KEY_ESC } },
>> +    { KE_KEY, KEY_F1,  { KEY_BRIGHTNESSDOWN } },
>> +    { KE_KEY, KEY_F2,  { KEY_BRIGHTNESSUP } },
>> +    { KE_KEY, KEY_F3,  { KEY_RESERVED } },
>> +    { KE_KEY, KEY_F4,  { KEY_RESERVED } },
>> +    { KE_KEY, KEY_F5,  { KEY_KBDILLUMDOWN } },
>> +    { KE_KEY, KEY_F6,  { KEY_KBDILLUMUP } },
>> +    { KE_KEY, KEY_F7,  { KEY_PREVIOUSSONG } },
>> +    { KE_KEY, KEY_F8,  { KEY_PLAYPAUSE } },
>> +    { KE_KEY, KEY_F9,  { KEY_NEXTSONG } },
>> +    { KE_KEY, KEY_F10, { KEY_MUTE } },
>> +    { KE_KEY, KEY_F11, { KEY_VOLUMEDOWN } },
>> +    { KE_KEY, KEY_F12, { KEY_VOLUMEUP } },
>> +    { KE_END, 0 }
>> +};
>> +
>> +static int appletb_kbd_set_mode(struct appletb_kbd *kbd, u8 mode)
>> +{
>> +    struct hid_report *report = kbd->mode_field->report;
>> +    struct hid_device *hdev = report->device;
>> +    int ret;
>> +
>> +    ret = hid_hw_power(hdev, PM_HINT_FULLON);
>> +    if (ret) {
>> +        hid_err(hdev, "Device didn't resume (%pe)\n", ERR_PTR(ret));
>> +        return ret;
>> +    }
>> +
>> +    ret = hid_set_field(kbd->mode_field, 0, mode);
>> +    if (ret) {
>> +        hid_err(hdev, "Failed to set mode field to %u (%pe)\n", mode, ERR_PTR(ret));
>> +        goto power_normal;
>> +    }
>> +
>> +    hid_hw_request(hdev, report, HID_REQ_SET_REPORT);
>> +
>> +    kbd->current_mode = mode;
>> +
>> +power_normal:
>> +    hid_hw_power(hdev, PM_HINT_NORMAL);
>> +
>> +    return ret;
>> +}
>> +
>> +static ssize_t mode_show(struct device *dev,
>> +             struct device_attribute *attr, char *buf)
>> +{
>> +    struct appletb_kbd *kbd = dev_get_drvdata(dev);
>> +
>> +    return sysfs_emit(buf, "%d\n", kbd->current_mode);
>> +}
>> +
>> +static ssize_t mode_store(struct device *dev,
>> +              struct device_attribute *attr,
>> +              const char *buf, size_t size)
>> +{
>> +    struct appletb_kbd *kbd = dev_get_drvdata(dev);
>> +    u8 mode;
>> +    int ret;
>> +
>> +    ret = kstrtou8(buf, 0, &mode);
>> +    if (ret)
>> +        return ret;
>> +
>> +    if (mode > APPLETB_KBD_MODE_MAX)
>> +        return -EINVAL;
>> +
>> +    ret = appletb_kbd_set_mode(kbd, mode);
>> +
>> +    return ret < 0 ? ret : size;
>> +}
>> +static DEVICE_ATTR_RW(mode);
>> +
>> +struct attribute *appletb_kbd_attrs[] = {
>> +    &dev_attr_mode.attr,
>> +    NULL
>> +};
>> +ATTRIBUTE_GROUPS(appletb_kbd);
>> +
>> +static int appletb_tb_key_to_slot(unsigned int code)
>> +{
>> +    switch (code) {
>> +    case KEY_ESC:
>> +        return 0;
>> +    case KEY_F1 ... KEY_F10:
>> +        return code - KEY_F1 + 1;
>> +    case KEY_F11 ... KEY_F12:
>> +        return code - KEY_F11 + 11;
>> +
>> +    default:
>> +        return -EINVAL;
>> +    }
>> +}
>> +
>> +static int appletb_kbd_hid_event(struct hid_device *hdev, struct hid_field *field,
>> +                      struct hid_usage *usage, __s32 value)
>> +{
>> +    struct appletb_kbd *kbd = hid_get_drvdata(hdev);
>> +    struct key_entry *translation;
>> +    struct input_dev *input;
>> +    int slot;
>> +
>> +    if ((usage->hid & HID_USAGE_PAGE) != HID_UP_KEYBOARD || usage->type != EV_KEY)
>> +        return 0;
>> +
>> +    input = field->hidinput->input;
>> +
>> +    /*
>> +     * Skip non-touch-bar keys.
>> +     *
>> +     * Either the touch bar itself or usbhid generate a slew of key-down
>> +     * events for all the meta keys. None of which we're at all interested
>> +     * in.
>> +     */
>> +    slot = appletb_tb_key_to_slot(usage->code);
>> +    if (slot < 0)
>> +        return 0;
>> +
>> +    translation = sparse_keymap_entry_from_scancode(input, usage->code);
> 
> You are missing a Kconfig depends or select here because when enabling
> this module, we can get
> 
> ERROR: modpost: "sparse_keymap_setup" [drivers/hid/hid-appletb-kbd.ko] undefined!
> ERROR: modpost: "sparse_keymap_entry_from_scancode" [drivers/hid/hid-appletb-kbd.ko] undefined!
> 

Hi

It's strange that "select INPUT_SPARSEKMAP" is causing the same error.

Can you please see if the error is still there with "depends on INPUT" as well as "select INPUT_SPARSEKMAP"

Thanks
Aditya

> FWIW, I tried "depend on INPUT_SPARSEKMAP" and "select
> INPUT_SPARSEKMAP", but in both cases the error was there, so I suspect
> there is one extra config to select (could be my script but if I can
> enter this state, I believe others will get into it as well).
> Cheers,
> Benjamin
> 
>> +
>> +    if (translation && kbd->current_mode == APPLETB_KBD_MODE_SPCL) {
>> +        input_event(input, usage->type, translation->keycode, value);
>> +
>> +        return 1;
>> +    }
>> +
>> +    return kbd->current_mode == APPLETB_KBD_MODE_OFF;
>> +}
>> +
>> +static int appletb_kbd_input_configured(struct hid_device *hdev, struct hid_input *hidinput)
>> +{
>> +    int idx;
>> +    struct input_dev *input = hidinput->input;
>> +
>> +    /*
>> +     * Clear various input capabilities that are blindly set by the hid
>> +     * driver (usbkbd.c)
>> +     */
>> +    memset(input->evbit, 0, sizeof(input->evbit));
>> +    memset(input->keybit, 0, sizeof(input->keybit));
>> +    memset(input->ledbit, 0, sizeof(input->ledbit));
>> +
>> +    __set_bit(EV_REP, input->evbit);
>> +
>> +    sparse_keymap_setup(input, appletb_kbd_keymap, NULL);
>> +
>> +    for (idx = 0; appletb_kbd_keymap[idx].type != KE_END; idx++) {
>> +        input_set_capability(input, EV_KEY, appletb_kbd_keymap[idx].code);
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int appletb_kbd_probe(struct hid_device *hdev, const struct hid_device_id *id)
>> +{
>> +    struct appletb_kbd *kbd;
>> +    struct device *dev = &hdev->dev;
>> +    struct hid_field *mode_field;
>> +    int ret;
>> +
>> +    ret = hid_parse(hdev);
>> +    if (ret)
>> +        return dev_err_probe(dev, ret, "HID parse failed\n");
>> +
>> +    mode_field = hid_find_field(hdev, HID_OUTPUT_REPORT,
>> +                    HID_GD_KEYBOARD, HID_USAGE_MODE);
>> +    if (!mode_field)
>> +        return -ENODEV;
>> +
>> +    kbd = devm_kzalloc(dev, sizeof(*kbd), GFP_KERNEL);
>> +    if (!kbd)
>> +        return -ENOMEM;
>> +
>> +    kbd->mode_field = mode_field;
>> +
>> +    ret = hid_hw_start(hdev, HID_CONNECT_HIDINPUT);
>> +    if (ret)
>> +        return dev_err_probe(dev, ret, "HID hw start failed\n");
>> +
>> +    ret = hid_hw_open(hdev);
>> +    if (ret) {
>> +        dev_err_probe(dev, ret, "HID hw open failed\n");
>> +        goto stop_hw;
>> +    }
>> +
>> +    ret = appletb_kbd_set_mode(kbd, appletb_tb_def_mode);
>> +    if (ret) {
>> +        dev_err_probe(dev, ret, "Failed to set touchbar mode\n");
>> +        goto close_hw;
>> +    }
>> +
>> +    hid_set_drvdata(hdev, kbd);
>> +
>> +    return 0;
>> +
>> +close_hw:
>> +    hid_hw_close(hdev);
>> +stop_hw:
>> +    hid_hw_stop(hdev);
>> +    return ret;
>> +}
>> +
>> +static void appletb_kbd_remove(struct hid_device *hdev)
>> +{
>> +    struct appletb_kbd *kbd = hid_get_drvdata(hdev);
>> +
>> +    appletb_kbd_set_mode(kbd, APPLETB_KBD_MODE_OFF);
>> +
>> +    hid_hw_close(hdev);
>> +    hid_hw_stop(hdev);
>> +}
>> +
>> +#ifdef CONFIG_PM
>> +static int appletb_kbd_suspend(struct hid_device *hdev, pm_message_t msg)
>> +{
>> +    struct appletb_kbd *kbd = hid_get_drvdata(hdev);
>> +
>> +    kbd->saved_mode = kbd->current_mode;
>> +    appletb_kbd_set_mode(kbd, APPLETB_KBD_MODE_OFF);
>> +
>> +    return 0;
>> +}
>> +
>> +static int appletb_kbd_reset_resume(struct hid_device *hdev)
>> +{
>> +    struct appletb_kbd *kbd = hid_get_drvdata(hdev);
>> +
>> +    appletb_kbd_set_mode(kbd, kbd->saved_mode);
>> +
>> +    return 0;
>> +}
>> +#endif
>> +
>> +static const struct hid_device_id appletb_kbd_hid_ids[] = {
>> +    /* MacBook Pro's 2018, 2019, with T2 chip: iBridge Display */
>> +    { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
>> +    { }
>> +};
>> +MODULE_DEVICE_TABLE(hid, appletb_kbd_hid_ids);
>> +
>> +static struct hid_driver appletb_kbd_hid_driver = {
>> +    .name = "hid-appletb-kbd",
>> +    .id_table = appletb_kbd_hid_ids,
>> +    .probe = appletb_kbd_probe,
>> +    .remove = appletb_kbd_remove,
>> +    .event = appletb_kbd_hid_event,
>> +    .input_configured = appletb_kbd_input_configured,
>> +#ifdef CONFIG_PM
>> +    .suspend = appletb_kbd_suspend,
>> +    .reset_resume = appletb_kbd_reset_resume,
>> +#endif
>> +    .driver.dev_groups = appletb_kbd_groups,
>> +};
>> +module_hid_driver(appletb_kbd_hid_driver);
>> +
>> +MODULE_AUTHOR("Ronald Tschalär");
>> +MODULE_AUTHOR("Kerem Karabay <[e-mail]>");
>> +MODULE_DESCRIPTION("MacBookPro Touch Bar Keyboard Mode Driver");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c
>> index 818d41a35..7c576d654 100644
>> --- a/drivers/hid/hid-quirks.c
>> +++ b/drivers/hid/hid-quirks.c
>> @@ -328,7 +328,6 @@ static const struct hid_device_id hid_have_special_driver[] = {
>>    { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_GEYSER1_TP_ONLY) },
>>    { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_2021) },
>>    { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_FINGERPRINT_2021) },
>> -    { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
>> #endif
>> #if IS_ENABLED(CONFIG_HID_APPLEIR)
>>    { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL) },
>> @@ -340,6 +339,9 @@ static const struct hid_device_id hid_have_special_driver[] = {
>> #if IS_ENABLED(CONFIG_HID_APPLETB_BL)
>>    { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT) },
>> #endif
>> +#if IS_ENABLED(CONFIG_HID_APPLETB_KBD)
>> +    { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
>> +#endif
>> #if IS_ENABLED(CONFIG_HID_ASUS)
>>    { HID_I2C_DEVICE(USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_I2C_KEYBOARD) },
>>    { HID_I2C_DEVICE(USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_I2C_TOUCHPAD) },
>> --
>> 2.43.0
>>

Patch

diff --git a/Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd b/Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd
new file mode 100644
index 000000000..2a19584d0
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-hid-appletb-kbd
@@ -0,0 +1,13 @@ 
+What:		/sys/bus/hid/drivers/hid-appletb-kbd/<dev>/mode
+Date:		September, 2023
+KernelVersion:	6.5
+Contact:	[e-mail]
+Description:
+		The set of keys displayed on the Touch Bar.
+		Valid values are:
+		== =================
+		0  Escape key only
+		1  Function keys
+		2  Media/brightness keys
+		3  None
+		== =================
diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 4988c1fb2..72b665eda 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -158,6 +158,17 @@  config HID_APPLETB_BL
 	  To compile this driver as a module, choose M here: the
 	  module will be called hid-appletb-bl.
 
+config HID_APPLETB_KBD
+	tristate "Apple Touch Bar Keyboard Mode"
+	depends on USB_HID
+	help
+	  Say Y here if you want support for the keyboard mode (escape,
+	  function, media and brightness keys) of Touch Bars on x86 MacBook
+	  Pros.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called hid-appletb-kbd.
+
 config HID_ASUS
 	tristate "Asus"
 	depends on USB_HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 1d825a474..d903c9a26 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -30,6 +30,7 @@  obj-$(CONFIG_HID_ACRUX)		+= hid-axff.o
 obj-$(CONFIG_HID_APPLE)		+= hid-apple.o
 obj-$(CONFIG_HID_APPLEIR)	+= hid-appleir.o
 obj-$(CONFIG_HID_APPLETB_BL)	+= hid-appletb-bl.o
+obj-$(CONFIG_HID_APPLETB_KBD)	+= hid-appletb-kbd.o
 obj-$(CONFIG_HID_CREATIVE_SB0540)	+= hid-creative-sb0540.o
 obj-$(CONFIG_HID_ASUS)		+= hid-asus.o
 obj-$(CONFIG_HID_AUREAL)	+= hid-aureal.o
diff --git a/drivers/hid/hid-appletb-kbd.c b/drivers/hid/hid-appletb-kbd.c
new file mode 100644
index 000000000..ecac68fc7
--- /dev/null
+++ b/drivers/hid/hid-appletb-kbd.c
@@ -0,0 +1,304 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Apple Touch Bar Keyboard Mode Driver
+ *
+ * Copyright (c) 2017-2018 Ronald Tschalär
+ * Copyright (c) 2022-2023 Kerem Karabay <[e-mail]>
+ * Copyright (c) 2024 Aditya Garg <[e-mail]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/hid.h>
+#include <linux/usb.h>
+#include <linux/input.h>
+#include <linux/sysfs.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/input/sparse-keymap.h>
+
+#include "hid-ids.h"
+
+#define APPLETB_KBD_MODE_ESC	0
+#define APPLETB_KBD_MODE_FN	1
+#define APPLETB_KBD_MODE_SPCL	2
+#define APPLETB_KBD_MODE_OFF	3
+#define APPLETB_KBD_MODE_MAX	APPLETB_KBD_MODE_OFF
+
+#define HID_USAGE_MODE		0x00ff0004
+
+static int appletb_tb_def_mode = APPLETB_KBD_MODE_SPCL;
+module_param_named(mode, appletb_tb_def_mode, int, 0444);
+MODULE_PARM_DESC(mode, "Default touchbar mode:\n"
+			 "    0 - escape key only\n"
+			 "    1 - function-keys\n"
+			 "    [2] - special keys");
+
+struct appletb_kbd {
+	struct hid_field *mode_field;
+
+	u8 saved_mode;
+	u8 current_mode;
+};
+
+static const struct key_entry appletb_kbd_keymap[] = {
+	{ KE_KEY, KEY_ESC, { KEY_ESC } },
+	{ KE_KEY, KEY_F1,  { KEY_BRIGHTNESSDOWN } },
+	{ KE_KEY, KEY_F2,  { KEY_BRIGHTNESSUP } },
+	{ KE_KEY, KEY_F3,  { KEY_RESERVED } },
+	{ KE_KEY, KEY_F4,  { KEY_RESERVED } },
+	{ KE_KEY, KEY_F5,  { KEY_KBDILLUMDOWN } },
+	{ KE_KEY, KEY_F6,  { KEY_KBDILLUMUP } },
+	{ KE_KEY, KEY_F7,  { KEY_PREVIOUSSONG } },
+	{ KE_KEY, KEY_F8,  { KEY_PLAYPAUSE } },
+	{ KE_KEY, KEY_F9,  { KEY_NEXTSONG } },
+	{ KE_KEY, KEY_F10, { KEY_MUTE } },
+	{ KE_KEY, KEY_F11, { KEY_VOLUMEDOWN } },
+	{ KE_KEY, KEY_F12, { KEY_VOLUMEUP } },
+	{ KE_END, 0 }
+};
+
+static int appletb_kbd_set_mode(struct appletb_kbd *kbd, u8 mode)
+{
+	struct hid_report *report = kbd->mode_field->report;
+	struct hid_device *hdev = report->device;
+	int ret;
+
+	ret = hid_hw_power(hdev, PM_HINT_FULLON);
+	if (ret) {
+		hid_err(hdev, "Device didn't resume (%pe)\n", ERR_PTR(ret));
+		return ret;
+	}
+
+	ret = hid_set_field(kbd->mode_field, 0, mode);
+	if (ret) {
+		hid_err(hdev, "Failed to set mode field to %u (%pe)\n", mode, ERR_PTR(ret));
+		goto power_normal;
+	}
+
+	hid_hw_request(hdev, report, HID_REQ_SET_REPORT);
+
+	kbd->current_mode = mode;
+
+power_normal:
+	hid_hw_power(hdev, PM_HINT_NORMAL);
+
+	return ret;
+}
+
+static ssize_t mode_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct appletb_kbd *kbd = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", kbd->current_mode);
+}
+
+static ssize_t mode_store(struct device *dev,
+			  struct device_attribute *attr,
+			  const char *buf, size_t size)
+{
+	struct appletb_kbd *kbd = dev_get_drvdata(dev);
+	u8 mode;
+	int ret;
+
+	ret = kstrtou8(buf, 0, &mode);
+	if (ret)
+		return ret;
+
+	if (mode > APPLETB_KBD_MODE_MAX)
+		return -EINVAL;
+
+	ret = appletb_kbd_set_mode(kbd, mode);
+
+	return ret < 0 ? ret : size;
+}
+static DEVICE_ATTR_RW(mode);
+
+struct attribute *appletb_kbd_attrs[] = {
+	&dev_attr_mode.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(appletb_kbd);
+
+static int appletb_tb_key_to_slot(unsigned int code)
+{
+	switch (code) {
+	case KEY_ESC:
+		return 0;
+	case KEY_F1 ... KEY_F10:
+		return code - KEY_F1 + 1;
+	case KEY_F11 ... KEY_F12:
+		return code - KEY_F11 + 11;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int appletb_kbd_hid_event(struct hid_device *hdev, struct hid_field *field,
+				      struct hid_usage *usage, __s32 value)
+{
+	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
+	struct key_entry *translation;
+	struct input_dev *input;
+	int slot;
+
+	if ((usage->hid & HID_USAGE_PAGE) != HID_UP_KEYBOARD || usage->type != EV_KEY)
+		return 0;
+
+	input = field->hidinput->input;
+
+	/*
+	 * Skip non-touch-bar keys.
+	 *
+	 * Either the touch bar itself or usbhid generate a slew of key-down
+	 * events for all the meta keys. None of which we're at all interested
+	 * in.
+	 */
+	slot = appletb_tb_key_to_slot(usage->code);
+	if (slot < 0)
+		return 0;
+
+	translation = sparse_keymap_entry_from_scancode(input, usage->code);
+
+	if (translation && kbd->current_mode == APPLETB_KBD_MODE_SPCL) {
+		input_event(input, usage->type, translation->keycode, value);
+
+		return 1;
+	}
+
+	return kbd->current_mode == APPLETB_KBD_MODE_OFF;
+}
+
+static int appletb_kbd_input_configured(struct hid_device *hdev, struct hid_input *hidinput)
+{
+	int idx;
+	struct input_dev *input = hidinput->input;
+
+	/*
+	 * Clear various input capabilities that are blindly set by the hid
+	 * driver (usbkbd.c)
+	 */
+	memset(input->evbit, 0, sizeof(input->evbit));
+	memset(input->keybit, 0, sizeof(input->keybit));
+	memset(input->ledbit, 0, sizeof(input->ledbit));
+
+	__set_bit(EV_REP, input->evbit);
+
+	sparse_keymap_setup(input, appletb_kbd_keymap, NULL);
+
+	for (idx = 0; appletb_kbd_keymap[idx].type != KE_END; idx++) {
+		input_set_capability(input, EV_KEY, appletb_kbd_keymap[idx].code);
+	}
+
+	return 0;
+}
+
+static int appletb_kbd_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct appletb_kbd *kbd;
+	struct device *dev = &hdev->dev;
+	struct hid_field *mode_field;
+	int ret;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return dev_err_probe(dev, ret, "HID parse failed\n");
+
+	mode_field = hid_find_field(hdev, HID_OUTPUT_REPORT,
+				    HID_GD_KEYBOARD, HID_USAGE_MODE);
+	if (!mode_field)
+		return -ENODEV;
+
+	kbd = devm_kzalloc(dev, sizeof(*kbd), GFP_KERNEL);
+	if (!kbd)
+		return -ENOMEM;
+
+	kbd->mode_field = mode_field;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDINPUT);
+	if (ret)
+		return dev_err_probe(dev, ret, "HID hw start failed\n");
+
+	ret = hid_hw_open(hdev);
+	if (ret) {
+		dev_err_probe(dev, ret, "HID hw open failed\n");
+		goto stop_hw;
+	}
+
+	ret = appletb_kbd_set_mode(kbd, appletb_tb_def_mode);
+	if (ret) {
+		dev_err_probe(dev, ret, "Failed to set touchbar mode\n");
+		goto close_hw;
+	}
+
+	hid_set_drvdata(hdev, kbd);
+
+	return 0;
+
+close_hw:
+	hid_hw_close(hdev);
+stop_hw:
+	hid_hw_stop(hdev);
+	return ret;
+}
+
+static void appletb_kbd_remove(struct hid_device *hdev)
+{
+	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
+
+	appletb_kbd_set_mode(kbd, APPLETB_KBD_MODE_OFF);
+
+	hid_hw_close(hdev);
+	hid_hw_stop(hdev);
+}
+
+#ifdef CONFIG_PM
+static int appletb_kbd_suspend(struct hid_device *hdev, pm_message_t msg)
+{
+	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
+
+	kbd->saved_mode = kbd->current_mode;
+	appletb_kbd_set_mode(kbd, APPLETB_KBD_MODE_OFF);
+
+	return 0;
+}
+
+static int appletb_kbd_reset_resume(struct hid_device *hdev)
+{
+	struct appletb_kbd *kbd = hid_get_drvdata(hdev);
+
+	appletb_kbd_set_mode(kbd, kbd->saved_mode);
+
+	return 0;
+}
+#endif
+
+static const struct hid_device_id appletb_kbd_hid_ids[] = {
+	/* MacBook Pro's 2018, 2019, with T2 chip: iBridge Display */
+	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, appletb_kbd_hid_ids);
+
+static struct hid_driver appletb_kbd_hid_driver = {
+	.name = "hid-appletb-kbd",
+	.id_table = appletb_kbd_hid_ids,
+	.probe = appletb_kbd_probe,
+	.remove = appletb_kbd_remove,
+	.event = appletb_kbd_hid_event,
+	.input_configured = appletb_kbd_input_configured,
+#ifdef CONFIG_PM
+	.suspend = appletb_kbd_suspend,
+	.reset_resume = appletb_kbd_reset_resume,
+#endif
+	.driver.dev_groups = appletb_kbd_groups,
+};
+module_hid_driver(appletb_kbd_hid_driver);
+
+MODULE_AUTHOR("Ronald Tschalär");
+MODULE_AUTHOR("Kerem Karabay <[e-mail]>");
+MODULE_DESCRIPTION("MacBookPro Touch Bar Keyboard Mode Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c
index 818d41a35..7c576d654 100644
--- a/drivers/hid/hid-quirks.c
+++ b/drivers/hid/hid-quirks.c
@@ -328,7 +328,6 @@  static const struct hid_device_id hid_have_special_driver[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_GEYSER1_TP_ONLY) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_2021) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_FINGERPRINT_2021) },
-	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
 #endif
 #if IS_ENABLED(CONFIG_HID_APPLEIR)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL) },
@@ -340,6 +339,9 @@  static const struct hid_device_id hid_have_special_driver[] = {
 #if IS_ENABLED(CONFIG_HID_APPLETB_BL)
 	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT) },
 #endif
+#if IS_ENABLED(CONFIG_HID_APPLETB_KBD)
+	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },
+#endif
 #if IS_ENABLED(CONFIG_HID_ASUS)
 	{ HID_I2C_DEVICE(USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_I2C_KEYBOARD) },
 	{ HID_I2C_DEVICE(USB_VENDOR_ID_ASUSTEK, USB_DEVICE_ID_ASUSTEK_I2C_TOUCHPAD) },