1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * INT3406 thermal driver for display participant device
4 *
5 * Copyright (C) 2016, Intel Corporation
6 * Authors: Aaron Lu <aaron.lu@intel.com>
7 */
8
9 #include <linux/module.h>
10 #include <linux/platform_device.h>
11 #include <linux/acpi.h>
12 #include <linux/backlight.h>
13 #include <linux/thermal.h>
14 #include <acpi/video.h>
15
16 #define INT3406_BRIGHTNESS_LIMITS_CHANGED 0x80
17
18 struct int3406_thermal_data {
19 int upper_limit;
20 int lower_limit;
21 acpi_handle handle;
22 struct acpi_video_device_brightness *br;
23 struct backlight_device *raw_bd;
24 struct thermal_cooling_device *cooling_dev;
25 };
26
27 /*
28 * According to the ACPI spec,
29 * "Each brightness level is represented by a number between 0 and 100,
30 * and can be thought of as a percentage. For example, 50 can be 50%
31 * power consumption or 50% brightness, as defined by the OEM."
32 *
33 * As int3406 device uses this value to communicate with the native
34 * graphics driver, we make the assumption that it represents
35 * the percentage of brightness only
36 */
37 #define ACPI_TO_RAW(v, d) (d->raw_bd->props.max_brightness * v / 100)
38 #define RAW_TO_ACPI(v, d) (v * 100 / d->raw_bd->props.max_brightness)
39
40 static int
int3406_thermal_get_max_state(struct thermal_cooling_device * cooling_dev,unsigned long * state)41 int3406_thermal_get_max_state(struct thermal_cooling_device *cooling_dev,
42 unsigned long *state)
43 {
44 struct int3406_thermal_data *d = cooling_dev->devdata;
45
46 *state = d->upper_limit - d->lower_limit;
47 return 0;
48 }
49
50 static int
int3406_thermal_set_cur_state(struct thermal_cooling_device * cooling_dev,unsigned long state)51 int3406_thermal_set_cur_state(struct thermal_cooling_device *cooling_dev,
52 unsigned long state)
53 {
54 struct int3406_thermal_data *d = cooling_dev->devdata;
55 int acpi_level, raw_level;
56
57 if (state > d->upper_limit - d->lower_limit)
58 return -EINVAL;
59
60 acpi_level = d->br->levels[d->upper_limit - state];
61
62 raw_level = ACPI_TO_RAW(acpi_level, d);
63
64 return backlight_device_set_brightness(d->raw_bd, raw_level);
65 }
66
67 static int
int3406_thermal_get_cur_state(struct thermal_cooling_device * cooling_dev,unsigned long * state)68 int3406_thermal_get_cur_state(struct thermal_cooling_device *cooling_dev,
69 unsigned long *state)
70 {
71 struct int3406_thermal_data *d = cooling_dev->devdata;
72 int acpi_level;
73 int index;
74
75 acpi_level = RAW_TO_ACPI(d->raw_bd->props.brightness, d);
76
77 /*
78 * There is no 1:1 mapping between the firmware interface level
79 * with the raw interface level, we will have to find one that is
80 * right above it.
81 */
82 for (index = d->lower_limit; index < d->upper_limit; index++) {
83 if (acpi_level <= d->br->levels[index])
84 break;
85 }
86
87 *state = d->upper_limit - index;
88 return 0;
89 }
90
91 static const struct thermal_cooling_device_ops video_cooling_ops = {
92 .get_max_state = int3406_thermal_get_max_state,
93 .get_cur_state = int3406_thermal_get_cur_state,
94 .set_cur_state = int3406_thermal_set_cur_state,
95 };
96
int3406_thermal_get_index(int * array,int nr,int value)97 static int int3406_thermal_get_index(int *array, int nr, int value)
98 {
99 int i;
100
101 for (i = 2; i < nr; i++) {
102 if (array[i] == value)
103 break;
104 }
105 return i == nr ? -ENOENT : i;
106 }
107
int3406_thermal_get_limit(struct int3406_thermal_data * d)108 static void int3406_thermal_get_limit(struct int3406_thermal_data *d)
109 {
110 acpi_status status;
111 unsigned long long lower_limit, upper_limit;
112
113 status = acpi_evaluate_integer(d->handle, "DDDL", NULL, &lower_limit);
114 if (ACPI_SUCCESS(status))
115 d->lower_limit = int3406_thermal_get_index(d->br->levels,
116 d->br->count, lower_limit);
117
118 status = acpi_evaluate_integer(d->handle, "DDPC", NULL, &upper_limit);
119 if (ACPI_SUCCESS(status))
120 d->upper_limit = int3406_thermal_get_index(d->br->levels,
121 d->br->count, upper_limit);
122
123 /* lower_limit and upper_limit should be always set */
124 d->lower_limit = d->lower_limit > 0 ? d->lower_limit : 2;
125 d->upper_limit = d->upper_limit > 0 ? d->upper_limit : d->br->count - 1;
126 }
127
int3406_notify(acpi_handle handle,u32 event,void * data)128 static void int3406_notify(acpi_handle handle, u32 event, void *data)
129 {
130 if (event == INT3406_BRIGHTNESS_LIMITS_CHANGED)
131 int3406_thermal_get_limit(data);
132 }
133
int3406_thermal_probe(struct platform_device * pdev)134 static int int3406_thermal_probe(struct platform_device *pdev)
135 {
136 struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
137 struct int3406_thermal_data *d;
138 struct backlight_device *bd;
139 int ret;
140
141 if (!ACPI_HANDLE(&pdev->dev))
142 return -ENODEV;
143
144 d = devm_kzalloc(&pdev->dev, sizeof(*d), GFP_KERNEL);
145 if (!d)
146 return -ENOMEM;
147 d->handle = ACPI_HANDLE(&pdev->dev);
148
149 bd = backlight_device_get_by_type(BACKLIGHT_RAW);
150 if (!bd)
151 return -ENODEV;
152 d->raw_bd = bd;
153
154 ret = acpi_video_get_levels(ACPI_COMPANION(&pdev->dev), &d->br, NULL);
155 if (ret)
156 return ret;
157
158 int3406_thermal_get_limit(d);
159
160 d->cooling_dev = thermal_cooling_device_register(acpi_device_bid(adev),
161 d, &video_cooling_ops);
162 if (IS_ERR(d->cooling_dev))
163 goto err;
164
165 ret = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
166 int3406_notify, d);
167 if (ret)
168 goto err_cdev;
169
170 platform_set_drvdata(pdev, d);
171
172 return 0;
173
174 err_cdev:
175 thermal_cooling_device_unregister(d->cooling_dev);
176 err:
177 kfree(d->br);
178 return -ENODEV;
179 }
180
int3406_thermal_remove(struct platform_device * pdev)181 static int int3406_thermal_remove(struct platform_device *pdev)
182 {
183 struct int3406_thermal_data *d = platform_get_drvdata(pdev);
184
185 thermal_cooling_device_unregister(d->cooling_dev);
186 kfree(d->br);
187 return 0;
188 }
189
190 static const struct acpi_device_id int3406_thermal_match[] = {
191 {"INT3406", 0},
192 {}
193 };
194
195 MODULE_DEVICE_TABLE(acpi, int3406_thermal_match);
196
197 static struct platform_driver int3406_thermal_driver = {
198 .probe = int3406_thermal_probe,
199 .remove = int3406_thermal_remove,
200 .driver = {
201 .name = "int3406 thermal",
202 .acpi_match_table = int3406_thermal_match,
203 },
204 };
205
206 module_platform_driver(int3406_thermal_driver);
207
208 MODULE_DESCRIPTION("INT3406 Thermal driver");
209 MODULE_LICENSE("GPL v2");
210