1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright (C) 2021 Thomas Weißschuh <thomas@weissschuh.net>
4  */
5 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
6 
7 #include <linux/acpi.h>
8 #include <linux/hwmon.h>
9 #include <linux/module.h>
10 #include <linux/wmi.h>
11 
12 #define GIGABYTE_WMI_GUID	"DEADBEEF-2001-0000-00A0-C90629100000"
13 #define NUM_TEMPERATURE_SENSORS	6
14 
15 static u8 usable_sensors_mask;
16 
17 enum gigabyte_wmi_commandtype {
18 	GIGABYTE_WMI_BUILD_DATE_QUERY       =   0x1,
19 	GIGABYTE_WMI_MAINBOARD_TYPE_QUERY   =   0x2,
20 	GIGABYTE_WMI_FIRMWARE_VERSION_QUERY =   0x4,
21 	GIGABYTE_WMI_MAINBOARD_NAME_QUERY   =   0x5,
22 	GIGABYTE_WMI_TEMPERATURE_QUERY      = 0x125,
23 };
24 
25 struct gigabyte_wmi_args {
26 	u32 arg1;
27 };
28 
29 static int gigabyte_wmi_perform_query(struct wmi_device *wdev,
30 				      enum gigabyte_wmi_commandtype command,
31 				      struct gigabyte_wmi_args *args, struct acpi_buffer *out)
32 {
33 	const struct acpi_buffer in = {
34 		.length = sizeof(*args),
35 		.pointer = args,
36 	};
37 
38 	acpi_status ret = wmidev_evaluate_method(wdev, 0x0, command, &in, out);
39 
40 	if (ACPI_FAILURE(ret))
41 		return -EIO;
42 
43 	return 0;
44 }
45 
46 static int gigabyte_wmi_query_integer(struct wmi_device *wdev,
47 				      enum gigabyte_wmi_commandtype command,
48 				      struct gigabyte_wmi_args *args, u64 *res)
49 {
50 	union acpi_object *obj;
51 	struct acpi_buffer result = { ACPI_ALLOCATE_BUFFER, NULL };
52 	int ret;
53 
54 	ret = gigabyte_wmi_perform_query(wdev, command, args, &result);
55 	if (ret)
56 		return ret;
57 	obj = result.pointer;
58 	if (obj && obj->type == ACPI_TYPE_INTEGER)
59 		*res = obj->integer.value;
60 	else
61 		ret = -EIO;
62 	kfree(result.pointer);
63 	return ret;
64 }
65 
66 static int gigabyte_wmi_temperature(struct wmi_device *wdev, u8 sensor, long *res)
67 {
68 	struct gigabyte_wmi_args args = {
69 		.arg1 = sensor,
70 	};
71 	u64 temp;
72 	acpi_status ret;
73 
74 	ret = gigabyte_wmi_query_integer(wdev, GIGABYTE_WMI_TEMPERATURE_QUERY, &args, &temp);
75 	if (ret == 0) {
76 		if (temp == 0)
77 			return -ENODEV;
78 		*res = (s8)temp * 1000; // value is a signed 8-bit integer
79 	}
80 	return ret;
81 }
82 
83 static int gigabyte_wmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
84 				   u32 attr, int channel, long *val)
85 {
86 	struct wmi_device *wdev = dev_get_drvdata(dev);
87 
88 	return gigabyte_wmi_temperature(wdev, channel, val);
89 }
90 
91 static umode_t gigabyte_wmi_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
92 					     u32 attr, int channel)
93 {
94 	return usable_sensors_mask & BIT(channel) ? 0444  : 0;
95 }
96 
97 static const struct hwmon_channel_info * const gigabyte_wmi_hwmon_info[] = {
98 	HWMON_CHANNEL_INFO(temp,
99 			   HWMON_T_INPUT,
100 			   HWMON_T_INPUT,
101 			   HWMON_T_INPUT,
102 			   HWMON_T_INPUT,
103 			   HWMON_T_INPUT,
104 			   HWMON_T_INPUT),
105 	NULL
106 };
107 
108 static const struct hwmon_ops gigabyte_wmi_hwmon_ops = {
109 	.read = gigabyte_wmi_hwmon_read,
110 	.is_visible = gigabyte_wmi_hwmon_is_visible,
111 };
112 
113 static const struct hwmon_chip_info gigabyte_wmi_hwmon_chip_info = {
114 	.ops = &gigabyte_wmi_hwmon_ops,
115 	.info = gigabyte_wmi_hwmon_info,
116 };
117 
118 static u8 gigabyte_wmi_detect_sensor_usability(struct wmi_device *wdev)
119 {
120 	int i;
121 	long temp;
122 	u8 r = 0;
123 
124 	for (i = 0; i < NUM_TEMPERATURE_SENSORS; i++) {
125 		if (!gigabyte_wmi_temperature(wdev, i, &temp))
126 			r |= BIT(i);
127 	}
128 	return r;
129 }
130 
131 static int gigabyte_wmi_probe(struct wmi_device *wdev, const void *context)
132 {
133 	struct device *hwmon_dev;
134 
135 	usable_sensors_mask = gigabyte_wmi_detect_sensor_usability(wdev);
136 	if (!usable_sensors_mask) {
137 		dev_info(&wdev->dev, "No temperature sensors usable");
138 		return -ENODEV;
139 	}
140 
141 	hwmon_dev = devm_hwmon_device_register_with_info(&wdev->dev, "gigabyte_wmi", wdev,
142 							 &gigabyte_wmi_hwmon_chip_info, NULL);
143 
144 	return PTR_ERR_OR_ZERO(hwmon_dev);
145 }
146 
147 static const struct wmi_device_id gigabyte_wmi_id_table[] = {
148 	{ GIGABYTE_WMI_GUID, NULL },
149 	{ }
150 };
151 
152 static struct wmi_driver gigabyte_wmi_driver = {
153 	.driver = {
154 		.name = "gigabyte-wmi",
155 	},
156 	.id_table = gigabyte_wmi_id_table,
157 	.probe = gigabyte_wmi_probe,
158 };
159 module_wmi_driver(gigabyte_wmi_driver);
160 
161 MODULE_DEVICE_TABLE(wmi, gigabyte_wmi_id_table);
162 MODULE_AUTHOR("Thomas Weißschuh <thomas@weissschuh.net>");
163 MODULE_DESCRIPTION("Gigabyte WMI temperature driver");
164 MODULE_LICENSE("GPL");
165