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 ATTRIBUTE_GROUPS(tbt);
55 
56 static const struct wmi_device_id intel_wmi_thunderbolt_id_table[] = {
57 	{ .guid_string = INTEL_WMI_THUNDERBOLT_GUID },
58 	{ },
59 };
60 
61 static struct wmi_driver intel_wmi_thunderbolt_driver = {
62 	.driver = {
63 		.name = "intel-wmi-thunderbolt",
64 		.dev_groups = tbt_groups,
65 	},
66 	.id_table = intel_wmi_thunderbolt_id_table,
67 };
68 
69 module_wmi_driver(intel_wmi_thunderbolt_driver);
70 
71 MODULE_DEVICE_TABLE(wmi, intel_wmi_thunderbolt_id_table);
72 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>");
73 MODULE_DESCRIPTION("Intel WMI Thunderbolt force power driver");
74 MODULE_LICENSE("GPL v2");
75