drivers/acpi/fan_hwmon.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * hwmon interface for the ACPI Fan driver.
   4  *
   5  * Copyright (C) 2024 Armin Wolf <W_Armin@gmx.de>
   6  */
   7
   8 #include <linux/acpi.h>
   9 #include <linux/device.h>
  10 #include <linux/err.h>
  11 #include <linux/hwmon.h>
  12 #include <linux/limits.h>
  13 #include <linux/types.h>
  14 #include <linux/units.h>
  15
  16 #include "fan.h"
  17
  18 /* Returned when the ACPI fan does not support speed reporting */
  19 #define FAN_SPEED_UNAVAILABLE   U32_MAX
  20 #define FAN_POWER_UNAVAILABLE   U32_MAX
  21
  22 static struct acpi_fan_fps *acpi_fan_get_current_fps(struct acpi_fan *fan, u64 control)
  23 {
  24         unsigned int i;
  25
  26         for (i = 0; i < fan->fps_count; i++) {
  27                 if (fan->fps[i].control == control)
  28                         return &fan->fps[i];
  29         }
  30
  31         return NULL;
  32 }
  33
  34 static umode_t acpi_fan_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_types type,
  35                                          u32 attr, int channel)
  36 {
  37         const struct acpi_fan *fan = drvdata;
  38         unsigned int i;
  39
  40         switch (type) {
  41         case hwmon_fan:
  42                 switch (attr) {
  43                 case hwmon_fan_input:
  44                         return 0444;
  45                 case hwmon_fan_target:
  46                         /*
  47                          * When in fine grain control mode, not every fan control value
  48                          * has an associated fan performance state.
  49                          */
  50                         if (fan->fif.fine_grain_ctrl)
  51                                 return 0;
  52
  53                         return 0444;
  54                 default:
  55                         return 0;
  56                 }
  57         case hwmon_power:
  58                 switch (attr) {
  59                 case hwmon_power_input:
  60                         /*
  61                          * When in fine grain control mode, not every fan control value
  62                          * has an associated fan performance state.
  63                          */
  64                         if (fan->fif.fine_grain_ctrl)
  65                                 return 0;
  66
  67                         /*
  68                          * When all fan performance states contain no valid power data,
  69                          * when the associated attribute should not be created.
  70                          */
  71                         for (i = 0; i < fan->fps_count; i++) {
  72                                 if (fan->fps[i].power != FAN_POWER_UNAVAILABLE)
  73                                         return 0444;
  74                         }
  75
  76                         return 0;
  77                 default:
  78                         return 0;
  79                 }
  80         default:
  81                 return 0;
  82         }
  83 }
  84
  85 static int acpi_fan_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
  86                                int channel, long *val)
  87 {
  88         struct acpi_device *adev = to_acpi_device(dev->parent);
  89         struct acpi_fan *fan = dev_get_drvdata(dev);
  90         struct acpi_fan_fps *fps;
  91         struct acpi_fan_fst fst;
  92         int ret;
  93
  94         ret = acpi_fan_get_fst(adev, &fst);
  95         if (ret < 0)
  96                 return ret;
  97
  98         switch (type) {
  99         case hwmon_fan:
 100                 switch (attr) {
 101                 case hwmon_fan_input:
 102                         if (fst.speed == FAN_SPEED_UNAVAILABLE)
 103                                 return -ENODEV;
 104
 105                         if (fst.speed > LONG_MAX)
 106                                 return -EOVERFLOW;
 107
 108                         *val = fst.speed;
 109                         return 0;
 110                 case hwmon_fan_target:
 111                         fps = acpi_fan_get_current_fps(fan, fst.control);
 112                         if (!fps)
 113                                 return -EIO;
 114
 115                         if (fps->speed > LONG_MAX)
 116                                 return -EOVERFLOW;
 117
 118                         *val = fps->speed;
 119                         return 0;
 120                 default:
 121                         return -EOPNOTSUPP;
 122                 }
 123         case hwmon_power:
 124                 switch (attr) {
 125                 case hwmon_power_input:
 126                         fps = acpi_fan_get_current_fps(fan, fst.control);
 127                         if (!fps)
 128                                 return -EIO;
 129
 130                         if (fps->power == FAN_POWER_UNAVAILABLE)
 131                                 return -ENODEV;
 132
 133                         if (fps->power > LONG_MAX / MICROWATT_PER_MILLIWATT)
 134                                 return -EOVERFLOW;
 135
 136                         *val = fps->power * MICROWATT_PER_MILLIWATT;
 137                         return 0;
 138                 default:
 139                         return -EOPNOTSUPP;
 140                 }
 141         default:
 142                 return -EOPNOTSUPP;
 143         }
 144 }
 145
 146 static const struct hwmon_ops acpi_fan_hwmon_ops = {
 147         .is_visible = acpi_fan_hwmon_is_visible,
 148         .read = acpi_fan_hwmon_read,
 149 };
 150
 151 static const struct hwmon_channel_info * const acpi_fan_hwmon_info[] = {
 152         HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET),
 153         HWMON_CHANNEL_INFO(power, HWMON_P_INPUT),
 154         NULL
 155 };
 156
 157 static const struct hwmon_chip_info acpi_fan_hwmon_chip_info = {
 158         .ops = &acpi_fan_hwmon_ops,
 159         .info = acpi_fan_hwmon_info,
 160 };
 161
 162 int devm_acpi_fan_create_hwmon(struct acpi_device *device)
 163 {
 164         struct acpi_fan *fan = acpi_driver_data(device);
 165         struct device *hdev;
 166
 167         hdev = devm_hwmon_device_register_with_info(&device->dev, "acpi_fan", fan,
 168                                                     &acpi_fan_hwmon_chip_info, NULL);
 169         return PTR_ERR_OR_ZERO(hdev);
 170 }