Pull esi-support into release branch
[linux-2.6] / drivers / macintosh / via-pmu-backlight.c
1 /*
2  * Backlight code for via-pmu
3  *
4  * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
5  * Copyright (C) 2001-2002 Benjamin Herrenschmidt
6  * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>
7  *
8  */
9
10 #include <asm/ptrace.h>
11 #include <linux/adb.h>
12 #include <linux/pmu.h>
13 #include <asm/backlight.h>
14 #include <asm/prom.h>
15
16 #define MAX_PMU_LEVEL 0xFF
17
18 static struct backlight_properties pmu_backlight_data;
19 static spinlock_t pmu_backlight_lock;
20 static int sleeping;
21 static u8 bl_curve[FB_BACKLIGHT_LEVELS];
22
23 static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
24 {
25         unsigned int i, flat, count, range = (max - min);
26
27         bl_curve[0] = off;
28
29         for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
30                 bl_curve[flat] = min;
31
32         count = FB_BACKLIGHT_LEVELS * 15 / 16;
33         for (i = 0; i < count; ++i)
34                 bl_curve[flat + i] = min + (range * (i + 1) / count);
35 }
36
37 static int pmu_backlight_curve_lookup(int value)
38 {
39         int level = (FB_BACKLIGHT_LEVELS - 1);
40         int i, max = 0;
41
42         /* Look for biggest value */
43         for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
44                 max = max((int)bl_curve[i], max);
45
46         /* Look for nearest value */
47         for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
48                 int diff = abs(bl_curve[i] - value);
49                 if (diff < max) {
50                         max = diff;
51                         level = i;
52                 }
53         }
54         return level;
55 }
56
57 static int pmu_backlight_get_level_brightness(int level)
58 {
59         int pmulevel;
60
61         /* Get and convert the value */
62         pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;
63         if (pmulevel < 0)
64                 pmulevel = 0;
65         else if (pmulevel > MAX_PMU_LEVEL)
66                 pmulevel = MAX_PMU_LEVEL;
67
68         return pmulevel;
69 }
70
71 static int pmu_backlight_update_status(struct backlight_device *bd)
72 {
73         struct adb_request req;
74         unsigned long flags;
75         int level = bd->props->brightness;
76
77         spin_lock_irqsave(&pmu_backlight_lock, flags);
78
79         /* Don't update brightness when sleeping */
80         if (sleeping)
81                 goto out;
82
83         if (bd->props->power != FB_BLANK_UNBLANK ||
84             bd->props->fb_blank != FB_BLANK_UNBLANK)
85                 level = 0;
86
87         if (level > 0) {
88                 int pmulevel = pmu_backlight_get_level_brightness(level);
89
90                 pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
91                 pmu_wait_complete(&req);
92
93                 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
94                         PMU_POW_BACKLIGHT | PMU_POW_ON);
95                 pmu_wait_complete(&req);
96         } else {
97                 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
98                         PMU_POW_BACKLIGHT | PMU_POW_OFF);
99                 pmu_wait_complete(&req);
100         }
101
102 out:
103         spin_unlock_irqrestore(&pmu_backlight_lock, flags);
104
105         return 0;
106 }
107
108 static int pmu_backlight_get_brightness(struct backlight_device *bd)
109 {
110         return bd->props->brightness;
111 }
112
113 static struct backlight_properties pmu_backlight_data = {
114         .owner          = THIS_MODULE,
115         .get_brightness = pmu_backlight_get_brightness,
116         .update_status  = pmu_backlight_update_status,
117         .max_brightness = (FB_BACKLIGHT_LEVELS - 1),
118 };
119
120 #ifdef CONFIG_PM
121 void pmu_backlight_set_sleep(int sleep)
122 {
123         unsigned long flags;
124
125         spin_lock_irqsave(&pmu_backlight_lock, flags);
126         sleeping = sleep;
127         spin_unlock_irqrestore(&pmu_backlight_lock, flags);
128 }
129 #endif /* CONFIG_PM */
130
131 void __init pmu_backlight_init()
132 {
133         struct backlight_device *bd;
134         char name[10];
135         int level, autosave;
136
137         /* Special case for the old PowerBook since I can't test on it */
138         autosave =
139                 machine_is_compatible("AAPL,3400/2400") ||
140                 machine_is_compatible("AAPL,3500");
141
142         if (!autosave &&
143             !pmac_has_backlight_type("pmu") &&
144             !machine_is_compatible("AAPL,PowerBook1998") &&
145             !machine_is_compatible("PowerBook1,1"))
146                 return;
147
148         snprintf(name, sizeof(name), "pmubl");
149
150         bd = backlight_device_register(name, NULL, &pmu_backlight_data);
151         if (IS_ERR(bd)) {
152                 printk("pmubl: Backlight registration failed\n");
153                 goto error;
154         }
155         pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
156
157         level = pmu_backlight_data.max_brightness;
158
159         if (autosave) {
160                 /* read autosaved value if available */
161                 struct adb_request req;
162                 pmu_request(&req, NULL, 2, 0xd9, 0);
163                 pmu_wait_complete(&req);
164
165                 level = pmu_backlight_curve_lookup(
166                                 (req.reply[0] >> 4) *
167                                 pmu_backlight_data.max_brightness / 15);
168         }
169
170         down(&bd->sem);
171         bd->props->brightness = level;
172         bd->props->power = FB_BLANK_UNBLANK;
173         bd->props->update_status(bd);
174         up(&bd->sem);
175
176         mutex_lock(&pmac_backlight_mutex);
177         if (!pmac_backlight)
178                 pmac_backlight = bd;
179         mutex_unlock(&pmac_backlight_mutex);
180
181         printk("pmubl: Backlight initialized (%s)\n", name);
182
183         return;
184
185 error:
186         return;
187 }