1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * WMI Thunderbolt driver
4  *
5  * Copyright (C) 2017 Dell Inc. All Rights Reserved.
6  */
7 
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 
10 #include <linux/acpi.h>
11 #include <linux/device.h>
12 #include <linux/fs.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/string.h>
16 #include <linux/sysfs.h>
17 #include <linux/types.h>
18 #include <linux/wmi.h>
19 
20 #define INTEL_WMI_THUNDERBOLT_GUID "86CCFD48-205E-4A77-9C48-2021CBEDE341"
21 
22 static ssize_t force_power_store(struct device *dev,
23 				 struct device_attribute *attr,
24 				 const char *buf, size_t count)
25 {
26 	struct acpi_buffer input;
27 	acpi_status status;
28 	u8 mode;
29 
30 	input.length = sizeof(u8);
31 	input.pointer = &mode;
32 	mode = hex_to_bin(buf[0]);
33 	dev_dbg(dev, "force_power: storing %#x\n", mode);
34 	if (mode == 0 || mode == 1) {
35 		status = wmi_evaluate_method(INTEL_WMI_THUNDERBOLT_GUID, 0, 1,
36 					     &input, NULL);
37 		if (ACPI_FAILURE(status)) {
38 			dev_dbg(dev, "force_power: failed to evaluate ACPI method\n");
39 			return -ENODEV;
40 		}
41 	} else {
42 		dev_dbg(dev, "force_power: unsupported mode\n");
43 		return -EINVAL;
44 	}
45 	return count;
46 }
47 
48 static DEVICE_ATTR_WO(force_power);
49 
50 static struct attribute *tbt_attrs[] = {
51 	&dev_attr_force_power.attr,
52 	NULL
53 };
54 
55 static const struct attribute_group tbt_attribute_group = {
56 	.attrs = tbt_attrs,
57 };
58 
59 static int intel_wmi_thunderbolt_probe(struct wmi_device *wdev,
60 				       const void *context)
61 {
62 	int ret;
63 
64 	ret = sysfs_create_group(&wdev->dev.kobj, &tbt_attribute_group);
65 	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
66 	return ret;
67 }
68 
69 static void intel_wmi_thunderbolt_remove(struct wmi_device *wdev)
70 {
71 	sysfs_remove_group(&wdev->dev.kobj, &tbt_attribute_group);
72 	kobject_uevent(&wdev->dev.kobj, KOBJ_CHANGE);
73 }
74 
75 static const struct wmi_device_id intel_wmi_thunderbolt_id_table[] = {
76 	{ .guid_string = INTEL_WMI_THUNDERBOLT_GUID },
77 	{ },
78 };
79 
80 static struct wmi_driver intel_wmi_thunderbolt_driver = {
81 	.driver = {
82 		.name = "intel-wmi-thunderbolt",
83 	},
84 	.probe = intel_wmi_thunderbolt_probe,
85 	.remove = intel_wmi_thunderbolt_remove,
86 	.id_table = intel_wmi_thunderbolt_id_table,
87 };
88 
89 module_wmi_driver(intel_wmi_thunderbolt_driver);
90 
91 MODULE_DEVICE_TABLE(wmi, intel_wmi_thunderbolt_id_table);
92 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>");
93 MODULE_DESCRIPTION("Intel WMI Thunderbolt force power driver");
94 MODULE_LICENSE("GPL v2");
95