tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Apple Touch Bar Backlight Driver
4 *
5 * Copyright (c) 2017-2018 Ronald Tschalär
6 * Copyright (c) 2022-2023 Kerem Karabay <kekrby@gmail.com>
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/hid.h>
12#include <linux/backlight.h>
13#include <linux/device.h>
14
15#include "hid-ids.h"
16
17#define APPLETB_BL_ON 1
18#define APPLETB_BL_DIM 3
19#define APPLETB_BL_OFF 4
20
21#define HID_UP_APPLEVENDOR_TB_BL 0xff120000
22
23#define HID_VD_APPLE_TB_BRIGHTNESS 0xff120001
24#define HID_USAGE_AUX1 0xff120020
25#define HID_USAGE_BRIGHTNESS 0xff120021
26
27static int appletb_bl_def_brightness = 2;
28module_param_named(brightness, appletb_bl_def_brightness, int, 0444);
29MODULE_PARM_DESC(brightness, "Default brightness:\n"
30 " 0 - Touchbar is off\n"
31 " 1 - Dim brightness\n"
32 " [2] - Full brightness");
33
34struct appletb_bl {
35 struct hid_field *aux1_field, *brightness_field;
36 struct backlight_device *bdev;
37
38 bool full_on;
39};
40
41static const u8 appletb_bl_brightness_map[] = {
42 APPLETB_BL_OFF,
43 APPLETB_BL_DIM,
44 APPLETB_BL_ON,
45};
46
47static int appletb_bl_set_brightness(struct appletb_bl *bl, u8 brightness)
48{
49 struct hid_report *report = bl->brightness_field->report;
50 struct hid_device *hdev = report->device;
51 int ret;
52
53 ret = hid_set_field(bl->aux1_field, 0, 1);
54 if (ret) {
55 hid_err(hdev, "Failed to set auxiliary field (%pe)\n", ERR_PTR(ret));
56 return ret;
57 }
58
59 ret = hid_set_field(bl->brightness_field, 0, brightness);
60 if (ret) {
61 hid_err(hdev, "Failed to set brightness field (%pe)\n", ERR_PTR(ret));
62 return ret;
63 }
64
65 if (!bl->full_on) {
66 ret = hid_hw_power(hdev, PM_HINT_FULLON);
67 if (ret < 0) {
68 hid_err(hdev, "Device didn't power on (%pe)\n", ERR_PTR(ret));
69 return ret;
70 }
71
72 bl->full_on = true;
73 }
74
75 hid_hw_request(hdev, report, HID_REQ_SET_REPORT);
76
77 if (brightness == APPLETB_BL_OFF) {
78 hid_hw_power(hdev, PM_HINT_NORMAL);
79 bl->full_on = false;
80 }
81
82 return 0;
83}
84
85static int appletb_bl_update_status(struct backlight_device *bdev)
86{
87 struct appletb_bl *bl = bl_get_data(bdev);
88 u8 brightness;
89
90 if (backlight_is_blank(bdev))
91 brightness = APPLETB_BL_OFF;
92 else
93 brightness = appletb_bl_brightness_map[backlight_get_brightness(bdev)];
94
95 return appletb_bl_set_brightness(bl, brightness);
96}
97
98static const struct backlight_ops appletb_bl_backlight_ops = {
99 .options = BL_CORE_SUSPENDRESUME,
100 .update_status = appletb_bl_update_status,
101};
102
103static int appletb_bl_probe(struct hid_device *hdev, const struct hid_device_id *id)
104{
105 struct hid_field *aux1_field, *brightness_field;
106 struct backlight_properties bl_props = { 0 };
107 struct device *dev = &hdev->dev;
108 struct appletb_bl *bl;
109 int ret;
110
111 ret = hid_parse(hdev);
112 if (ret)
113 return dev_err_probe(dev, ret, "HID parse failed\n");
114
115 aux1_field = hid_find_field(hdev, HID_FEATURE_REPORT,
116 HID_VD_APPLE_TB_BRIGHTNESS, HID_USAGE_AUX1);
117
118 brightness_field = hid_find_field(hdev, HID_FEATURE_REPORT,
119 HID_VD_APPLE_TB_BRIGHTNESS, HID_USAGE_BRIGHTNESS);
120
121 if (!aux1_field || !brightness_field)
122 return -ENODEV;
123
124 if (aux1_field->report != brightness_field->report)
125 return dev_err_probe(dev, -ENODEV, "Encountered unexpected report structure\n");
126
127 bl = devm_kzalloc(dev, sizeof(*bl), GFP_KERNEL);
128 if (!bl)
129 return -ENOMEM;
130
131 ret = hid_hw_start(hdev, HID_CONNECT_DRIVER);
132 if (ret)
133 return dev_err_probe(dev, ret, "HID hardware start failed\n");
134
135 ret = hid_hw_open(hdev);
136 if (ret) {
137 dev_err_probe(dev, ret, "HID hardware open failed\n");
138 goto stop_hw;
139 }
140
141 bl->aux1_field = aux1_field;
142 bl->brightness_field = brightness_field;
143
144 ret = appletb_bl_set_brightness(bl,
145 appletb_bl_brightness_map[(appletb_bl_def_brightness > 2) ? 2 : appletb_bl_def_brightness]);
146
147 if (ret) {
148 dev_err_probe(dev, ret, "Failed to set default touch bar brightness to %d\n",
149 appletb_bl_def_brightness);
150 goto close_hw;
151 }
152
153 bl_props.type = BACKLIGHT_RAW;
154 bl_props.max_brightness = ARRAY_SIZE(appletb_bl_brightness_map) - 1;
155
156 bl->bdev = devm_backlight_device_register(dev, "appletb_backlight", dev, bl,
157 &appletb_bl_backlight_ops, &bl_props);
158 if (IS_ERR(bl->bdev)) {
159 ret = PTR_ERR(bl->bdev);
160 dev_err_probe(dev, ret, "Failed to register backlight device\n");
161 goto close_hw;
162 }
163
164 hid_set_drvdata(hdev, bl);
165
166 return 0;
167
168close_hw:
169 hid_hw_close(hdev);
170stop_hw:
171 hid_hw_stop(hdev);
172
173 return ret;
174}
175
176static void appletb_bl_remove(struct hid_device *hdev)
177{
178 struct appletb_bl *bl = hid_get_drvdata(hdev);
179
180 appletb_bl_set_brightness(bl, APPLETB_BL_OFF);
181
182 hid_hw_close(hdev);
183 hid_hw_stop(hdev);
184}
185
186static const struct hid_device_id appletb_bl_hid_ids[] = {
187 /* MacBook Pro's 2018, 2019, with T2 chip: iBridge DFR Brightness */
188 { HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT) },
189 { }
190};
191MODULE_DEVICE_TABLE(hid, appletb_bl_hid_ids);
192
193static struct hid_driver appletb_bl_hid_driver = {
194 .name = "hid-appletb-bl",
195 .id_table = appletb_bl_hid_ids,
196 .probe = appletb_bl_probe,
197 .remove = appletb_bl_remove,
198};
199module_hid_driver(appletb_bl_hid_driver);
200
201MODULE_AUTHOR("Ronald Tschalär");
202MODULE_AUTHOR("Kerem Karabay <kekrby@gmail.com>");
203MODULE_DESCRIPTION("MacBook Pro Touch Bar Backlight driver");
204MODULE_LICENSE("GPL");