Commit 1fd41e5e authored by Kerem Karabay's avatar Kerem Karabay Committed by Jiri Kosina
Browse files

HID: hid-appletb-bl: add driver for the backlight of Apple Touch Bars 



This commit adds a driver for the backlight of Apple Touch Bars on x86
Macs. Note that currently only T2 Macs are supported.

This driver is based on previous work done by Ronald Tschalär
<ronald@innovation.ch>.

Signed-off-by: default avatarKerem Karabay <kekrby@gmail.com>
Co-developed-by: default avatarAditya Garg <gargaditya08@live.com>
Signed-off-by: default avatarAditya Garg <gargaditya08@live.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.com>
parent 27c02784

drivers/hid/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -148,6 +148,16 @@ config HID_APPLEIR 


	Say Y here if you want support for Apple infrared remote control.



config HID_APPLETB_BL

	tristate "Apple Touch Bar Backlight"

	depends on BACKLIGHT_CLASS_DEVICE

	help

	  Say Y here if you want support for the backlight of Touch Bars on x86

	  MacBook Pros.



	  To compile this driver as a module, choose M here: the

	  module will be called hid-appletb-bl.



config HID_ASUS

	tristate "Asus"

	depends on USB_HID

drivers/hid/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ obj-$(CONFIG_HID_ALPS) += hid-alps.o 
obj-$(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_CREATIVE_SB0540)	+= hid-creative-sb0540.o

obj-$(CONFIG_HID_ASUS)		+= hid-asus.o

obj-$(CONFIG_HID_AUREAL)	+= hid-aureal.o

drivers/hid/hid-appletb-bl.c

0 → 100644
+207 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Apple Touch Bar Backlight Driver

 *

 * Copyright (c) 2017-2018 Ronald Tschalär

 * Copyright (c) 2022-2023 Kerem Karabay <kekrby@gmail.com>

 */



#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/hid.h>

#include <linux/backlight.h>

#include <linux/device.h>



#include "hid-ids.h"



#define APPLETB_BL_ON			1

#define APPLETB_BL_DIM			3

#define APPLETB_BL_OFF			4



#define HID_UP_APPLEVENDOR_TB_BL	0xff120000



#define HID_VD_APPLE_TB_BRIGHTNESS	0xff120001

#define HID_USAGE_AUX1			0xff120020

#define HID_USAGE_BRIGHTNESS		0xff120021



static int appletb_bl_def_brightness = 2;

module_param_named(brightness, appletb_bl_def_brightness, int, 0444);

MODULE_PARM_DESC(brightness, "Default brightness:\n"

			 "    0 - Touchbar is off\n"

			 "    1 - Dim brightness\n"

			 "    [2] - Full brightness");



struct appletb_bl {

	struct hid_field *aux1_field, *brightness_field;

	struct backlight_device *bdev;



	bool full_on;

};



static const u8 appletb_bl_brightness_map[] = {

	APPLETB_BL_OFF,

	APPLETB_BL_DIM,

	APPLETB_BL_ON,

};



static int appletb_bl_set_brightness(struct appletb_bl *bl, u8 brightness)

{

	struct hid_report *report = bl->brightness_field->report;

	struct hid_device *hdev = report->device;

	int ret;



	ret = hid_set_field(bl->aux1_field, 0, 1);

	if (ret) {

		hid_err(hdev, "Failed to set auxiliary field (%pe)\n", ERR_PTR(ret));

		return ret;

	}



	ret = hid_set_field(bl->brightness_field, 0, brightness);

	if (ret) {

		hid_err(hdev, "Failed to set brightness field (%pe)\n", ERR_PTR(ret));

		return ret;

	}



	if (!bl->full_on) {

		ret = hid_hw_power(hdev, PM_HINT_FULLON);

		if (ret < 0) {

			hid_err(hdev, "Device didn't power on (%pe)\n", ERR_PTR(ret));

			return ret;

		}



		bl->full_on = true;

	}



	hid_hw_request(hdev, report, HID_REQ_SET_REPORT);



	if (brightness == APPLETB_BL_OFF) {

		hid_hw_power(hdev, PM_HINT_NORMAL);

		bl->full_on = false;

	}



	return 0;

}



static int appletb_bl_update_status(struct backlight_device *bdev)

{

	struct appletb_bl *bl = bl_get_data(bdev);

	u8 brightness;



	if (backlight_is_blank(bdev))

		brightness = APPLETB_BL_OFF;

	else

		brightness = appletb_bl_brightness_map[backlight_get_brightness(bdev)];



	return appletb_bl_set_brightness(bl, brightness);

}



static const struct backlight_ops appletb_bl_backlight_ops = {

	.options = BL_CORE_SUSPENDRESUME,

	.update_status = appletb_bl_update_status,

};



static int appletb_bl_probe(struct hid_device *hdev, const struct hid_device_id *id)

{

	struct hid_field *aux1_field, *brightness_field;

	struct backlight_properties bl_props = { 0 };

	struct device *dev = &hdev->dev;

	struct appletb_bl *bl;

	int ret;



	ret = hid_parse(hdev);

	if (ret)

		return dev_err_probe(dev, ret, "HID parse failed\n");



	aux1_field = hid_find_field(hdev, HID_FEATURE_REPORT,

				    HID_VD_APPLE_TB_BRIGHTNESS, HID_USAGE_AUX1);



	brightness_field = hid_find_field(hdev, HID_FEATURE_REPORT,

					  HID_VD_APPLE_TB_BRIGHTNESS, HID_USAGE_BRIGHTNESS);



	if (!aux1_field || !brightness_field)

		return -ENODEV;



	if (aux1_field->report != brightness_field->report)

		return dev_err_probe(dev, -ENODEV, "Encountered unexpected report structure\n");



	bl = devm_kzalloc(dev, sizeof(*bl), GFP_KERNEL);

	if (!bl)

		return -ENOMEM;



	ret = hid_hw_start(hdev, HID_CONNECT_DRIVER);

	if (ret)

		return dev_err_probe(dev, ret, "HID hardware start failed\n");



	ret = hid_hw_open(hdev);

	if (ret) {

		dev_err_probe(dev, ret, "HID hardware open failed\n");

		goto stop_hw;

	}



	bl->aux1_field = aux1_field;

	bl->brightness_field = brightness_field;



	if (appletb_bl_def_brightness == 0)

		ret = appletb_bl_set_brightness(bl, APPLETB_BL_OFF);

	else if (appletb_bl_def_brightness == 1)

		ret = appletb_bl_set_brightness(bl, APPLETB_BL_DIM);

	else

		ret = appletb_bl_set_brightness(bl, APPLETB_BL_ON);



	if (ret) {

		dev_err_probe(dev, ret, "Failed to set touch bar brightness to off\n");

		goto close_hw;

	}



	bl_props.type = BACKLIGHT_RAW;

	bl_props.max_brightness = ARRAY_SIZE(appletb_bl_brightness_map) - 1;



	bl->bdev = devm_backlight_device_register(dev, "appletb_backlight", dev, bl,

						  &appletb_bl_backlight_ops, &bl_props);

	if (IS_ERR(bl->bdev)) {

		ret = PTR_ERR(bl->bdev);

		dev_err_probe(dev, ret, "Failed to register backlight device\n");

		goto close_hw;

	}



	hid_set_drvdata(hdev, bl);



	return 0;



close_hw:

	hid_hw_close(hdev);

stop_hw:

	hid_hw_stop(hdev);



	return ret;

}



static void appletb_bl_remove(struct hid_device *hdev)

{

	struct appletb_bl *bl = hid_get_drvdata(hdev);



	appletb_bl_set_brightness(bl, APPLETB_BL_OFF);



	hid_hw_close(hdev);

	hid_hw_stop(hdev);

}



static const struct hid_device_id appletb_bl_hid_ids[] = {

	/* MacBook Pro's 2018, 2019, with T2 chip: iBridge DFR Brightness */

	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT) },

	{ }

};

MODULE_DEVICE_TABLE(hid, appletb_bl_hid_ids);



static struct hid_driver appletb_bl_hid_driver = {

	.name = "hid-appletb-bl",

	.id_table = appletb_bl_hid_ids,

	.probe = appletb_bl_probe,

	.remove = appletb_bl_remove,

};

module_hid_driver(appletb_bl_hid_driver);



MODULE_AUTHOR("Ronald Tschalär");

MODULE_AUTHOR("Kerem Karabay <kekrby@gmail.com>");

MODULE_DESCRIPTION("MacBookPro Touch Bar Backlight Driver");

MODULE_LICENSE("GPL");

drivers/hid/hid-quirks.c

+3 −1
Original line number Diff line number Diff line
@@ -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_BACKLIGHT) },

	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_DISPLAY) },

#endif

#if IS_ENABLED(CONFIG_HID_APPLEIR)
@@ -338,6 +337,9 @@ static const struct hid_device_id hid_have_special_driver[] = { 
	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL4) },

	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL5) },

#endif

#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_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) },