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 27 static int appletb_bl_def_brightness = 2; 28 module_param_named(brightness, appletb_bl_def_brightness, int, 0444); 29 MODULE_PARM_DESC(brightness, "Default brightness:\n" 30 " 0 - Touchbar is off\n" 31 " 1 - Dim brightness\n" 32 " [2] - Full brightness"); 33 34 struct appletb_bl { 35 struct hid_field *aux1_field, *brightness_field; 36 struct backlight_device *bdev; 37 38 bool full_on; 39 }; 40 41 static const u8 appletb_bl_brightness_map[] = { 42 APPLETB_BL_OFF, 43 APPLETB_BL_DIM, 44 APPLETB_BL_ON, 45 }; 46 47 static 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 85 static 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 98 static const struct backlight_ops appletb_bl_backlight_ops = { 99 .options = BL_CORE_SUSPENDRESUME, 100 .update_status = appletb_bl_update_status, 101 }; 102 103 static 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; 167 168 close_hw: 169 hid_hw_close(hdev); 170 stop_hw: 171 hid_hw_stop(hdev); 172 173 return ret; 174 } 175 176 static 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 } 185 186 static 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 }; 191 MODULE_DEVICE_TABLE(hid, appletb_bl_hid_ids); 192 193 static 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 }; 199 module_hid_driver(appletb_bl_hid_driver); 200 201 MODULE_AUTHOR("Ronald Tschalär"); 202 MODULE_AUTHOR("Kerem Karabay <kekrby@gmail.com>"); 203 MODULE_DESCRIPTION("MacBook Pro Touch Bar Backlight driver"); 204 MODULE_LICENSE("GPL"); 205