summaryrefslogtreecommitdiffstats
path: root/drivers/macintosh/via-pmu-backlight.c
blob: 89ed51571b62b003a69e17c0e66bb346e97b01ae (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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
// SPDX-License-Identifier: GPL-2.0
/*
 * Backlight code for via-pmu
 *
 * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
 * Copyright (C) 2001-2002 Benjamin Herrenschmidt
 * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>
 *
 */

#include <asm/ptrace.h>
#include <linux/adb.h>
#include <linux/pmu.h>
#include <asm/backlight.h>
#include <asm/prom.h>

#define MAX_PMU_LEVEL 0xFF

static const struct backlight_ops pmu_backlight_data;
static DEFINE_SPINLOCK(pmu_backlight_lock);
static int sleeping, uses_pmu_bl;
static u8 bl_curve[FB_BACKLIGHT_LEVELS];

static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
{
	int i, flat, count, range = (max - min);

	bl_curve[0] = off;

	for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
		bl_curve[flat] = min;

	count = FB_BACKLIGHT_LEVELS * 15 / 16;
	for (i = 0; i < count; ++i)
		bl_curve[flat + i] = min + (range * (i + 1) / count);
}

static int pmu_backlight_curve_lookup(int value)
{
	int level = (FB_BACKLIGHT_LEVELS - 1);
	int i, max = 0;

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

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

static int pmu_backlight_get_level_brightness(int level)
{
	int pmulevel;

	/* Get and convert the value */
	pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;
	if (pmulevel < 0)
		pmulevel = 0;
	else if (pmulevel > MAX_PMU_LEVEL)
		pmulevel = MAX_PMU_LEVEL;

	return pmulevel;
}

static int __pmu_backlight_update_status(struct backlight_device *bd)
{
	struct adb_request req;
	int level = bd->props.brightness;


	if (bd->props.power != FB_BLANK_UNBLANK ||
	    bd->props.fb_blank != FB_BLANK_UNBLANK)
		level = 0;

	if (level > 0) {
		int pmulevel = pmu_backlight_get_level_brightness(level);

		pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
		pmu_wait_complete(&req);

		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
			PMU_POW_BACKLIGHT | PMU_POW_ON);
		pmu_wait_complete(&req);
	} else {
		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
			PMU_POW_BACKLIGHT | PMU_POW_OFF);
		pmu_wait_complete(&req);
	}

	return 0;
}

static int pmu_backlight_update_status(struct backlight_device *bd)
{
	unsigned long flags;
	int rc = 0;

	spin_lock_irqsave(&pmu_backlight_lock, flags);
	/* Don't update brightness when sleeping */
	if (!sleeping)
		rc = __pmu_backlight_update_status(bd);
	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
	return rc;
}


static const struct backlight_ops pmu_backlight_data = {
	.update_status	= pmu_backlight_update_status,

};

#ifdef CONFIG_PM
void pmu_backlight_set_sleep(int sleep)
{
	unsigned long flags;

	spin_lock_irqsave(&pmu_backlight_lock, flags);
	sleeping = sleep;
	if (pmac_backlight && uses_pmu_bl) {
		if (sleep) {
			struct adb_request req;

			pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
				    PMU_POW_BACKLIGHT | PMU_POW_OFF);
			pmu_wait_complete(&req);
		} else
			__pmu_backlight_update_status(pmac_backlight);
	}
	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
}
#endif /* CONFIG_PM */

void __init pmu_backlight_init()
{
	struct backlight_properties props;
	struct backlight_device *bd;
	char name[10];
	int level, autosave;

	/* Special case for the old PowerBook since I can't test on it */
	autosave =
		of_machine_is_compatible("AAPL,3400/2400") ||
		of_machine_is_compatible("AAPL,3500");

	if (!autosave &&
	    !pmac_has_backlight_type("pmu") &&
	    !of_machine_is_compatible("AAPL,PowerBook1998") &&
	    !of_machine_is_compatible("PowerBook1,1"))
		return;

	snprintf(name, sizeof(name), "pmubl");

	memset(&props, 0, sizeof(struct backlight_properties));
	props.type = BACKLIGHT_PLATFORM;
	props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
	bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
				       &props);
	if (IS_ERR(bd)) {
		printk(KERN_ERR "PMU Backlight registration failed\n");
		return;
	}
	uses_pmu_bl = 1;
	pmu_backlight_init_curve(0x7F, 0x46, 0x0E);

	level = bd->props.max_brightness;

	if (autosave) {
		/* read autosaved value if available */
		struct adb_request req;
		pmu_request(&req, NULL, 2, 0xd9, 0);
		pmu_wait_complete(&req);

		level = pmu_backlight_curve_lookup(
				(req.reply[0] >> 4) *
				bd->props.max_brightness / 15);
	}

	bd->props.brightness = level;
	bd->props.power = FB_BLANK_UNBLANK;
	backlight_update_status(bd);

	printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
}