aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/platforms/powermac/backlight.c
blob: c7a27eddca6d4b96f002f2c5b5a3725933849089 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
/*
 * Miscellaneous procedures for dealing with the PowerMac hardware.
 * Contains support for the backlight.
 *
 *   Copyright (C) 2000 Benjamin Herrenschmidt
 *   Copyright (C) 2006 Michael Hanselmann <linux-kernel@hansmi.ch>
 *
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <asm/prom.h>
#include <asm/backlight.h>

#define OLD_BACKLIGHT_MAX 15

/* Protect the pmac_backlight variable */
DEFINE_MUTEX(pmac_backlight_mutex);

/* Main backlight storage
 *
 * Backlight drivers in this variable are required to have the "props"
 * attribute set and to have an update_status function.
 *
 * We can only store one backlight here, but since Apple laptops have only one
 * internal display, it doesn't matter. Other backlight drivers can be used
 * independently.
 *
 * Lock ordering:
 * pmac_backlight_mutex (global, main backlight)
 *   pmac_backlight->sem (backlight class)
 */
struct backlight_device *pmac_backlight;

int pmac_has_backlight_type(const char *type)
{
	struct device_node* bk_node = find_devices("backlight");

	if (bk_node) {
		char *prop = get_property(bk_node, "backlight-control", NULL);
		if (prop && strncmp(prop, type, strlen(type)) == 0)
			return 1;
	}

	return 0;
}

int pmac_backlight_curve_lookup(struct fb_info *info, int value)
{
	int level = (FB_BACKLIGHT_LEVELS - 1);

	if (info && info->bl_dev) {
		int i, max = 0;

		/* Look for biggest value */
		for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
			max = max((int)info->bl_curve[i], max);

		/* Look for nearest value */
		for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
			int diff = abs(info->bl_curve[i] - value);
			if (diff < max) {
				max = diff;
				level = i;
			}
		}

	}

	return level;
}

static void pmac_backlight_key(int direction)
{
	mutex_lock(&pmac_backlight_mutex);
	if (pmac_backlight) {
		struct backlight_properties *props;
		int brightness;

		down(&pmac_backlight->sem);
		props = pmac_backlight->props;

		brightness = props->brightness +
			((direction?-1:1) * (props->max_brightness / 15));

		if (brightness < 0)
			brightness = 0;
		else if (brightness > props->max_brightness)
			brightness = props->max_brightness;

		props->brightness = brightness;
		props->update_status(pmac_backlight);

		up(&pmac_backlight->sem);
	}
	mutex_unlock(&pmac_backlight_mutex);
}

void pmac_backlight_key_up()
{
	pmac_backlight_key(0);
}

void pmac_backlight_key_down()
{
	pmac_backlight_key(1);
}

int pmac_backlight_set_legacy_brightness(int brightness)
{
	int error = -ENXIO;

	mutex_lock(&pmac_backlight_mutex);
	if (pmac_backlight) {
		struct backlight_properties *props;

		down(&pmac_backlight->sem);
		props = pmac_backlight->props;
		props->brightness = brightness *
			(props->max_brightness + 1) /
			(OLD_BACKLIGHT_MAX + 1);

		if (props->brightness > props->max_brightness)
			props->brightness = props->max_brightness;
		else if (props->brightness < 0)
			props->brightness = 0;

		props->update_status(pmac_backlight);
		up(&pmac_backlight->sem);

		error = 0;
	}
	mutex_unlock(&pmac_backlight_mutex);

	return error;
}

int pmac_backlight_get_legacy_brightness()
{
	int result = -ENXIO;

	mutex_lock(&pmac_backlight_mutex);
	if (pmac_backlight) {
		struct backlight_properties *props;

		down(&pmac_backlight->sem);
		props = pmac_backlight->props;

		result = props->brightness *
			(OLD_BACKLIGHT_MAX + 1) /
			(props->max_brightness + 1);

		up(&pmac_backlight->sem);
	}
	mutex_unlock(&pmac_backlight_mutex);

	return result;
}