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
15static u8 usable_sensors_mask;
16
17enum 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
25struct gigabyte_wmi_args {
26	u32 arg1;
27};
28
29static 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
46static 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
66static 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
83static 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
91static 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
97static 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
108static const struct hwmon_ops gigabyte_wmi_hwmon_ops = {
109	.read = gigabyte_wmi_hwmon_read,
110	.is_visible = gigabyte_wmi_hwmon_is_visible,
111};
112
113static const struct hwmon_chip_info gigabyte_wmi_hwmon_chip_info = {
114	.ops = &gigabyte_wmi_hwmon_ops,
115	.info = gigabyte_wmi_hwmon_info,
116};
117
118static 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
131static 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
147static const struct wmi_device_id gigabyte_wmi_id_table[] = {
148	{ GIGABYTE_WMI_GUID, NULL },
149	{ }
150};
151
152static 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};
159module_wmi_driver(gigabyte_wmi_driver);
160
161MODULE_DEVICE_TABLE(wmi, gigabyte_wmi_id_table);
162MODULE_AUTHOR("Thomas Weißschuh <thomas@weissschuh.net>");
163MODULE_DESCRIPTION("Gigabyte WMI temperature driver");
164MODULE_LICENSE("GPL");
165