backlight: Fix external uses of backlight internal semaphore
[linux-3.10.git] / 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 DEFINE_SPINLOCK(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         .get_brightness = pmu_backlight_get_brightness,
115         .update_status  = pmu_backlight_update_status,
116         .max_brightness = (FB_BACKLIGHT_LEVELS - 1),
117 };
118
119 #ifdef CONFIG_PM
120 void pmu_backlight_set_sleep(int sleep)
121 {
122         unsigned long flags;
123
124         spin_lock_irqsave(&pmu_backlight_lock, flags);
125         sleeping = sleep;
126         spin_unlock_irqrestore(&pmu_backlight_lock, flags);
127 }
128 #endif /* CONFIG_PM */
129
130 void __init pmu_backlight_init()
131 {
132         struct backlight_device *bd;
133         char name[10];
134         int level, autosave;
135
136         /* Special case for the old PowerBook since I can't test on it */
137         autosave =
138                 machine_is_compatible("AAPL,3400/2400") ||
139                 machine_is_compatible("AAPL,3500");
140
141         if (!autosave &&
142             !pmac_has_backlight_type("pmu") &&
143             !machine_is_compatible("AAPL,PowerBook1998") &&
144             !machine_is_compatible("PowerBook1,1"))
145                 return;
146
147         snprintf(name, sizeof(name), "pmubl");
148
149         bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data);
150         if (IS_ERR(bd)) {
151                 printk("pmubl: Backlight registration failed\n");
152                 goto error;
153         }
154         pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
155
156         level = pmu_backlight_data.max_brightness;
157
158         if (autosave) {
159                 /* read autosaved value if available */
160                 struct adb_request req;
161                 pmu_request(&req, NULL, 2, 0xd9, 0);
162                 pmu_wait_complete(&req);
163
164                 level = pmu_backlight_curve_lookup(
165                                 (req.reply[0] >> 4) *
166                                 pmu_backlight_data.max_brightness / 15);
167         }
168
169         bd->props->brightness = level;
170         bd->props->power = FB_BLANK_UNBLANK;
171         backlight_update_status(bd);
172
173         mutex_lock(&pmac_backlight_mutex);
174         if (!pmac_backlight)
175                 pmac_backlight = bd;
176         mutex_unlock(&pmac_backlight_mutex);
177
178         printk("pmubl: Backlight initialized (%s)\n", name);
179
180         return;
181
182 error:
183         return;
184 }