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 
acpi_fan_get_current_fps(struct acpi_fan * fan,u64 control)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 
acpi_fan_hwmon_is_visible(const void * drvdata,enum hwmon_sensor_types type,u32 attr,int channel)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 
acpi_fan_hwmon_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)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_device *adev = to_acpi_device(dev->parent);
97 	struct acpi_fan *fan = dev_get_drvdata(dev);
98 	struct acpi_fan_fps *fps;
99 	struct acpi_fan_fst fst;
100 	int ret;
101 
102 	ret = acpi_fan_get_fst(adev, &fst);
103 	if (ret < 0)
104 		return ret;
105 
106 	switch (type) {
107 	case hwmon_fan:
108 		switch (attr) {
109 		case hwmon_fan_input:
110 			if (fst.speed == FAN_SPEED_UNAVAILABLE)
111 				return -ENODEV;
112 
113 			if (fst.speed > LONG_MAX)
114 				return -EOVERFLOW;
115 
116 			*val = fst.speed;
117 			return 0;
118 		case hwmon_fan_target:
119 			fps = acpi_fan_get_current_fps(fan, fst.control);
120 			if (!fps)
121 				return -EIO;
122 
123 			if (fps->speed > LONG_MAX)
124 				return -EOVERFLOW;
125 
126 			*val = fps->speed;
127 			return 0;
128 		default:
129 			return -EOPNOTSUPP;
130 		}
131 	case hwmon_power:
132 		switch (attr) {
133 		case hwmon_power_input:
134 			fps = acpi_fan_get_current_fps(fan, fst.control);
135 			if (!fps)
136 				return -EIO;
137 
138 			if (fps->power == FAN_POWER_UNAVAILABLE)
139 				return -ENODEV;
140 
141 			if (fps->power > LONG_MAX / MICROWATT_PER_MILLIWATT)
142 				return -EOVERFLOW;
143 
144 			*val = fps->power * MICROWATT_PER_MILLIWATT;
145 			return 0;
146 		default:
147 			return -EOPNOTSUPP;
148 		}
149 	default:
150 		return -EOPNOTSUPP;
151 	}
152 }
153 
154 static const struct hwmon_ops acpi_fan_hwmon_ops = {
155 	.is_visible = acpi_fan_hwmon_is_visible,
156 	.read = acpi_fan_hwmon_read,
157 };
158 
159 static const struct hwmon_channel_info * const acpi_fan_hwmon_info[] = {
160 	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_TARGET),
161 	HWMON_CHANNEL_INFO(power, HWMON_P_INPUT),
162 	NULL
163 };
164 
165 static const struct hwmon_chip_info acpi_fan_hwmon_chip_info = {
166 	.ops = &acpi_fan_hwmon_ops,
167 	.info = acpi_fan_hwmon_info,
168 };
169 
devm_acpi_fan_create_hwmon(struct acpi_device * device)170 int devm_acpi_fan_create_hwmon(struct acpi_device *device)
171 {
172 	struct acpi_fan *fan = acpi_driver_data(device);
173 	struct device *hdev;
174 
175 	hdev = devm_hwmon_device_register_with_info(&device->dev, "acpi_fan", fan,
176 						    &acpi_fan_hwmon_chip_info, NULL);
177 	return PTR_ERR_OR_ZERO(hdev);
178 }
179