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");