drivers/hwmon/nzxt-kraken2.c

   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 <linux/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
  21 static const char *const kraken2_temp_label[] = {
  22         "Coolant",
  23 };
  24
  25 static const char *const kraken2_fan_label[] = {
  26         "Fan",
  27         "Pump",
  28 };
  29
  30 struct 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
  38 static int kraken2_read(struct device *dev, enum hwmon_sensor_types type,
  39                         u32 attr, int channel, long *val)
  40 {
  41         struct kraken2_priv_data *priv = dev_get_drvdata(dev);
  42
  43         if (time_after(jiffies, priv->updated + STATUS_VALIDITY * HZ))
  44                 return -ENODATA;
  45
  46         switch (type) {
  47         case hwmon_temp:
  48                 *val = priv->temp_input[channel];
  49                 break;
  50         case hwmon_fan:
  51                 *val = priv->fan_input[channel];
  52                 break;
  53         default:
  54                 return -EOPNOTSUPP; /* unreachable */
  55         }
  56
  57         return 0;
  58 }
  59
  60 static int kraken2_read_string(struct device *dev, enum hwmon_sensor_types type,
  61                                u32 attr, int channel, const char **str)
  62 {
  63         switch (type) {
  64         case hwmon_temp:
  65                 *str = kraken2_temp_label[channel];
  66                 break;
  67         case hwmon_fan:
  68                 *str = kraken2_fan_label[channel];
  69                 break;
  70         default:
  71                 return -EOPNOTSUPP; /* unreachable */
  72         }
  73         return 0;
  74 }
  75
  76 static const struct hwmon_ops kraken2_hwmon_ops = {
  77         .visible = 0444,
  78         .read = kraken2_read,
  79         .read_string = kraken2_read_string,
  80 };
  81
  82 static const struct hwmon_channel_info * const kraken2_info[] = {
  83         HWMON_CHANNEL_INFO(temp,
  84                            HWMON_T_INPUT | HWMON_T_LABEL),
  85         HWMON_CHANNEL_INFO(fan,
  86                            HWMON_F_INPUT | HWMON_F_LABEL,
  87                            HWMON_F_INPUT | HWMON_F_LABEL),
  88         NULL
  89 };
  90
  91 static const struct hwmon_chip_info kraken2_chip_info = {
  92         .ops = &kraken2_hwmon_ops,
  93         .info = kraken2_info,
  94 };
  95
  96 static int kraken2_raw_event(struct hid_device *hdev,
  97                              struct hid_report *report, u8 *data, int size)
  98 {
  99         struct kraken2_priv_data *priv;
 100
 101         if (size < 7 || report->id != STATUS_REPORT_ID)
 102                 return 0;
 103
 104         priv = hid_get_drvdata(hdev);
 105
 106         /*
 107          * The fractional byte of the coolant temperature has been observed to
 108          * be in the interval [1,9], but some of these steps are also
 109          * consistently skipped for certain integer parts.
 110          *
 111          * For the lack of a better idea, assume that the resolution is 0.1°C,
 112          * and that the missing steps are artifacts of how the firmware
 113          * processes the raw sensor data.
 114          */
 115         priv->temp_input[0] = data[1] * 1000 + data[2] * 100;
 116
 117         priv->fan_input[0] = get_unaligned_be16(data + 3);
 118         priv->fan_input[1] = get_unaligned_be16(data + 5);
 119
 120         priv->updated = jiffies;
 121
 122         return 0;
 123 }
 124
 125 static int kraken2_probe(struct hid_device *hdev,
 126                          const struct hid_device_id *id)
 127 {
 128         struct kraken2_priv_data *priv;
 129         int ret;
 130
 131         priv = devm_kzalloc(&hdev->dev, sizeof(*priv), GFP_KERNEL);
 132         if (!priv)
 133                 return -ENOMEM;
 134
 135         priv->hid_dev = hdev;
 136         hid_set_drvdata(hdev, priv);
 137
 138         /*
 139          * Initialize ->updated to STATUS_VALIDITY seconds in the past, making
 140          * the initial empty data invalid for kraken2_read without the need for
 141          * a special case there.
 142          */
 143         priv->updated = jiffies - STATUS_VALIDITY * HZ;
 144
 145         ret = hid_parse(hdev);
 146         if (ret) {
 147                 hid_err(hdev, "hid parse failed with %d\n", ret);
 148                 return ret;
 149         }
 150
 151         /*
 152          * Enable hidraw so existing user-space tools can continue to work.
 153          */
 154         ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
 155         if (ret) {
 156                 hid_err(hdev, "hid hw start failed with %d\n", ret);
 157                 return ret;
 158         }
 159
 160         ret = hid_hw_open(hdev);
 161         if (ret) {
 162                 hid_err(hdev, "hid hw open failed with %d\n", ret);
 163                 goto fail_and_stop;
 164         }
 165
 166         priv->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "kraken2",
 167                                                           priv, &kraken2_chip_info,
 168                                                           NULL);
 169         if (IS_ERR(priv->hwmon_dev)) {
 170                 ret = PTR_ERR(priv->hwmon_dev);
 171                 hid_err(hdev, "hwmon registration failed with %d\n", ret);
 172                 goto fail_and_close;
 173         }
 174
 175         return 0;
 176
 177 fail_and_close:
 178         hid_hw_close(hdev);
 179 fail_and_stop:
 180         hid_hw_stop(hdev);
 181         return ret;
 182 }
 183
 184 static void kraken2_remove(struct hid_device *hdev)
 185 {
 186         struct kraken2_priv_data *priv = hid_get_drvdata(hdev);
 187
 188         hwmon_device_unregister(priv->hwmon_dev);
 189
 190         hid_hw_close(hdev);
 191         hid_hw_stop(hdev);
 192 }
 193
 194 static const struct hid_device_id kraken2_table[] = {
 195         { HID_USB_DEVICE(0x1e71, 0x170e) }, /* NZXT Kraken X42/X52/X62/X72 */
 196         { }
 197 };
 198
 199 MODULE_DEVICE_TABLE(hid, kraken2_table);
 200
 201 static struct hid_driver kraken2_driver = {
 202         .name = "nzxt-kraken2",
 203         .id_table = kraken2_table,
 204         .probe = kraken2_probe,
 205         .remove = kraken2_remove,
 206         .raw_event = kraken2_raw_event,
 207 };
 208
 209 static int __init kraken2_init(void)
 210 {
 211         return hid_register_driver(&kraken2_driver);
 212 }
 213
 214 static void __exit kraken2_exit(void)
 215 {
 216         hid_unregister_driver(&kraken2_driver);
 217 }
 218
 219 /*
 220  * When compiled into the kernel, initialize after the hid bus.
 221  */
 222 late_initcall(kraken2_init);
 223 module_exit(kraken2_exit);
 224
 225 MODULE_LICENSE("GPL");
 226 MODULE_AUTHOR("Jonas Malaco <jonas@protocubo.io>");
 227 MODULE_DESCRIPTION("Hwmon driver for NZXT Kraken X42/X52/X62/X72 coolers");