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
18struct 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
40static int
41int3406_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
50static int
51int3406_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
67static int
68int3406_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
91static 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
97static 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
108static 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
128static 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
134static 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
174err_cdev:
175	thermal_cooling_device_unregister(d->cooling_dev);
176err:
177	kfree(d->br);
178	return -ENODEV;
179}
180
181static 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
190static const struct acpi_device_id int3406_thermal_match[] = {
191	{"INT3406", 0},
192	{}
193};
194
195MODULE_DEVICE_TABLE(acpi, int3406_thermal_match);
196
197static 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
206module_platform_driver(int3406_thermal_driver);
207
208MODULE_DESCRIPTION("INT3406 Thermal driver");
209MODULE_LICENSE("GPL v2");
210