1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * nzxt-kraken2.c - hwmon driver for NZXT Kraken X42/X52/X62/X72 coolers
4 *
5 * The device asynchronously sends HID reports (with id 0x04) twice a second to
6 * communicate current fan speed, pump speed and coolant temperature.  The
7 * device does not respond to Get_Report requests for this status report.
8 *
9 * Copyright 2019-2021  Jonas Malaco <jonas@protocubo.io>
10 */
11
12#include <asm/unaligned.h>
13#include <linux/hid.h>
14#include <linux/hwmon.h>
15#include <linux/jiffies.h>
16#include <linux/module.h>
17
18#define STATUS_REPORT_ID	0x04
19#define STATUS_VALIDITY		2 /* seconds; equivalent to 4 missed updates */
20
21static const char *const kraken2_temp_label[] = {
22	"Coolant",
23};
24
25static const char *const kraken2_fan_label[] = {
26	"Fan",
27	"Pump",
28};
29
30struct kraken2_priv_data {
31	struct hid_device *hid_dev;
32	struct device *hwmon_dev;
33	s32 temp_input[1];
34	u16 fan_input[2];
35	unsigned long updated; /* jiffies */
36};
37
38static umode_t kraken2_is_visible(const void *data,
39				  enum hwmon_sensor_types type,
40				  u32 attr, int channel)
41{
42	return 0444;
43}
44
45static int kraken2_read(struct device *dev, enum hwmon_sensor_types type,
46			u32 attr, int channel, long *val)
47{
48	struct kraken2_priv_data *priv = dev_get_drvdata(dev);
49
50	if (time_after(jiffies, priv->updated + STATUS_VALIDITY * HZ))
51		return -ENODATA;
52
53	switch (type) {
54	case hwmon_temp:
55		*val = priv->temp_input[channel];
56		break;
57	case hwmon_fan:
58		*val = priv->fan_input[channel];
59		break;
60	default:
61		return -EOPNOTSUPP; /* unreachable */
62	}
63
64	return 0;
65}
66
67static int kraken2_read_string(struct device *dev, enum hwmon_sensor_types type,
68			       u32 attr, int channel, const char **str)
69{
70	switch (type) {
71	case hwmon_temp:
72		*str = kraken2_temp_label[channel];
73		break;
74	case hwmon_fan:
75		*str = kraken2_fan_label[channel];
76		break;
77	default:
78		return -EOPNOTSUPP; /* unreachable */
79	}
80	return 0;
81}
82
83static const struct hwmon_ops kraken2_hwmon_ops = {
84	.is_visible = kraken2_is_visible,
85	.read = kraken2_read,
86	.read_string = kraken2_read_string,
87};
88
89static const struct hwmon_channel_info * const kraken2_info[] = {
90	HWMON_CHANNEL_INFO(temp,
91			   HWMON_T_INPUT | HWMON_T_LABEL),
92	HWMON_CHANNEL_INFO(fan,
93			   HWMON_F_INPUT | HWMON_F_LABEL,
94			   HWMON_F_INPUT | HWMON_F_LABEL),
95	NULL
96};
97
98static const struct hwmon_chip_info kraken2_chip_info = {
99	.ops = &kraken2_hwmon_ops,
100	.info = kraken2_info,
101};
102
103static int kraken2_raw_event(struct hid_device *hdev,
104			     struct hid_report *report, u8 *data, int size)
105{
106	struct kraken2_priv_data *priv;
107
108	if (size < 7 || report->id != STATUS_REPORT_ID)
109		return 0;
110
111	priv = hid_get_drvdata(hdev);
112
113	/*
114	 * The fractional byte of the coolant temperature has been observed to
115	 * be in the interval [1,9], but some of these steps are also
116	 * consistently skipped for certain integer parts.
117	 *
118	 * For the lack of a better idea, assume that the resolution is 0.1��C,
119	 * and that the missing steps are artifacts of how the firmware
120	 * processes the raw sensor data.
121	 */
122	priv->temp_input[0] = data[1] * 1000 + data[2] * 100;
123
124	priv->fan_input[0] = get_unaligned_be16(data + 3);
125	priv->fan_input[1] = get_unaligned_be16(data + 5);
126
127	priv->updated = jiffies;
128
129	return 0;
130}
131
132static int kraken2_probe(struct hid_device *hdev,
133			 const struct hid_device_id *id)
134{
135	struct kraken2_priv_data *priv;
136	int ret;
137
138	priv = devm_kzalloc(&hdev->dev, sizeof(*priv), GFP_KERNEL);
139	if (!priv)
140		return -ENOMEM;
141
142	priv->hid_dev = hdev;
143	hid_set_drvdata(hdev, priv);
144
145	/*
146	 * Initialize ->updated to STATUS_VALIDITY seconds in the past, making
147	 * the initial empty data invalid for kraken2_read without the need for
148	 * a special case there.
149	 */
150	priv->updated = jiffies - STATUS_VALIDITY * HZ;
151
152	ret = hid_parse(hdev);
153	if (ret) {
154		hid_err(hdev, "hid parse failed with %d\n", ret);
155		return ret;
156	}
157
158	/*
159	 * Enable hidraw so existing user-space tools can continue to work.
160	 */
161	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
162	if (ret) {
163		hid_err(hdev, "hid hw start failed with %d\n", ret);
164		return ret;
165	}
166
167	ret = hid_hw_open(hdev);
168	if (ret) {
169		hid_err(hdev, "hid hw open failed with %d\n", ret);
170		goto fail_and_stop;
171	}
172
173	priv->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "kraken2",
174							  priv, &kraken2_chip_info,
175							  NULL);
176	if (IS_ERR(priv->hwmon_dev)) {
177		ret = PTR_ERR(priv->hwmon_dev);
178		hid_err(hdev, "hwmon registration failed with %d\n", ret);
179		goto fail_and_close;
180	}
181
182	return 0;
183
184fail_and_close:
185	hid_hw_close(hdev);
186fail_and_stop:
187	hid_hw_stop(hdev);
188	return ret;
189}
190
191static void kraken2_remove(struct hid_device *hdev)
192{
193	struct kraken2_priv_data *priv = hid_get_drvdata(hdev);
194
195	hwmon_device_unregister(priv->hwmon_dev);
196
197	hid_hw_close(hdev);
198	hid_hw_stop(hdev);
199}
200
201static const struct hid_device_id kraken2_table[] = {
202	{ HID_USB_DEVICE(0x1e71, 0x170e) }, /* NZXT Kraken X42/X52/X62/X72 */
203	{ }
204};
205
206MODULE_DEVICE_TABLE(hid, kraken2_table);
207
208static struct hid_driver kraken2_driver = {
209	.name = "nzxt-kraken2",
210	.id_table = kraken2_table,
211	.probe = kraken2_probe,
212	.remove = kraken2_remove,
213	.raw_event = kraken2_raw_event,
214};
215
216static int __init kraken2_init(void)
217{
218	return hid_register_driver(&kraken2_driver);
219}
220
221static void __exit kraken2_exit(void)
222{
223	hid_unregister_driver(&kraken2_driver);
224}
225
226/*
227 * When compiled into the kernel, initialize after the hid bus.
228 */
229late_initcall(kraken2_init);
230module_exit(kraken2_exit);
231
232MODULE_LICENSE("GPL");
233MODULE_AUTHOR("Jonas Malaco <jonas@protocubo.io>");
234MODULE_DESCRIPTION("Hwmon driver for NZXT Kraken X42/X52/X62/X72 coolers");
235