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// 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;
ret = appletb_bl_set_brightness(bl,
appletb_bl_brightness_map[(appletb_bl_def_brightness > 2) ? 2 : appletb_bl_def_brightness]);
if (ret) {
dev_err_probe(dev, ret, "Failed to set default touch bar brightness to %d\n",
appletb_bl_def_brightness);
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("MacBook Pro Touch Bar Backlight driver");
MODULE_LICENSE("GPL");
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