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 <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
  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 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
  45 static 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
  67 static 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
  83 static 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
  89 static const struct hwmon_channel_info *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
  98 static const struct hwmon_chip_info kraken2_chip_info = {
  99         .ops = &kraken2_hwmon_ops,
 100         .info = kraken2_info,
 101 };
 102
 103 static 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
 132 static 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                 goto fail_and_stop;
 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_close;
 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
 184 fail_and_close:
 185         hid_hw_close(hdev);
 186 fail_and_stop:
 187         hid_hw_stop(hdev);
 188         return ret;
 189 }
 190
 191 static 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
 201 static const struct hid_device_id kraken2_table[] = {
 202         { HID_USB_DEVICE(0x1e71, 0x170e) }, /* NZXT Kraken X42/X52/X62/X72 */
 203         { }
 204 };
 205
 206 MODULE_DEVICE_TABLE(hid, kraken2_table);
 207
 208 static 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
 216 static int __init kraken2_init(void)
 217 {
 218         return hid_register_driver(&kraken2_driver);
 219 }
 220
 221 static 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  */
 229 late_initcall(kraken2_init);
 230 module_exit(kraken2_exit);
 231
 232 MODULE_LICENSE("GPL");
 233 MODULE_AUTHOR("Jonas Malaco <jonas@protocubo.io>");
 234 MODULE_DESCRIPTION("Hwmon driver for NZXT Kraken X42/X52/X62/X72 coolers");