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 /* Only acpi4 fans support fan control. */ 47 if (!fan->acpi4) 48 return 0; 49 50 /* 51 * When in fine grain control mode, not every fan control value 52 * has an associated fan performance state. 53 */ 54 if (fan->fif.fine_grain_ctrl) 55 return 0; 56 57 return 0444; 58 default: 59 return 0; 60 } 61 case hwmon_power: 62 switch (attr) { 63 case hwmon_power_input: 64 /* Only acpi4 fans support fan control. */ 65 if (!fan->acpi4) 66 return 0; 67 68 /* 69 * When in fine grain control mode, not every fan control value 70 * has an associated fan performance state. 71 */ 72 if (fan->fif.fine_grain_ctrl) 73 return 0; 74 75 /* 76 * When all fan performance states contain no valid power data, 77 * when the associated attribute should not be created. 78 */ 79 for (i = 0; i < fan->fps_count; i++) { 80 if (fan->fps[i].power != FAN_POWER_UNAVAILABLE) 81 return 0444; 82 } 83 84 return 0; 85 default: 86 return 0; 87 } 88 default: 89 return 0; 90 } 91 } 92 93 static int acpi_fan_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, 94 int channel, long *val) 95 { 96 struct acpi_fan *fan = dev_get_drvdata(dev); 97 struct acpi_fan_fps *fps; 98 struct acpi_fan_fst fst; 99 int ret; 100 101 ret = acpi_fan_get_fst(fan->handle, &fst); 102 if (ret < 0) 103 return ret; 104 105 switch (type) { 106 case hwmon_fan: 107 switch (attr) { 108 case hwmon_fan_input: 109 if (fst.speed == FAN_SPEED_UNAVAILABLE) 110 return -ENODEV; 111 112 if (fst.speed > LONG_MAX) 113 return -EOVERFLOW; 114 115 *val = fst.speed; 116 return 0; 117 case hwmon_fan_target: 118 fps = acpi_fan_get_current_fps(fan, fst.control); 119 if (!fps) 120 return -EIO; 121 122 if (fps->speed > LONG_MAX) 123 return -EOVERFLOW; 124 125 *val = fps->speed; 126 return 0; 127 default: 128 return -EOPNOTSUPP; 129 } 130 case hwmon_power: 131 switch (attr) { 132 case hwmon_power_input: 133 fps = acpi_fan_get_current_fps(fan, fst.control); 134 if (!fps) 135 return -EIO; 136 137 if (fps->power == FAN_POWER_UNAVAILABLE) 138 return -ENODEV; 139 140 if (fps->power > LONG_MAX / MICROWATT_PER_MILLIWATT) 141 return -EOVERFLOW; 142 143 *val = fps->power * MICROWATT_PER_MILLIWATT; 144 return 0; 145 default: 146 return -EOPNOTSUPP; 147 } 148 default: 149 return -EOPNOTSUPP; 150 } 151 } 152 153 static const struct hwmon_ops acpi_fan_hwmon_ops = { 154 .is_visible = acpi_fan_hwmon_is_visible, 155 .read = acpi_fan_hwmon_read, 156 }; 157 158 static const struct hwmon_channel_info * const acpi_fan_hwmon_info[] = { 159 HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET), 160 HWMON_CHANNEL_INFO(power, HWMON_P_INPUT), 161 NULL 162 }; 163 164 static const struct hwmon_chip_info acpi_fan_hwmon_chip_info = { 165 .ops = &acpi_fan_hwmon_ops, 166 .info = acpi_fan_hwmon_info, 167 }; 168 169 int devm_acpi_fan_create_hwmon(struct device *dev) 170 { 171 struct acpi_fan *fan = dev_get_drvdata(dev); 172 struct device *hdev; 173 174 hdev = devm_hwmon_device_register_with_info(dev, "acpi_fan", fan, &acpi_fan_hwmon_chip_info, 175 NULL); 176 return PTR_ERR_OR_ZERO(hdev); 177 } 178