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