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 const struct backlight_ops pmu_backlight_data;
19 static DEFINE_SPINLOCK(pmu_backlight_lock);
20 static int sleeping, uses_pmu_bl;
21 static u8 bl_curve[FB_BACKLIGHT_LEVELS];
22
pmu_backlight_init_curve(u8 off,u8 min,u8 max)23 static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
24 {
25 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
pmu_backlight_curve_lookup(int value)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
pmu_backlight_get_level_brightness(int level)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
__pmu_backlight_update_status(struct backlight_device * bd)71 static int __pmu_backlight_update_status(struct backlight_device *bd)
72 {
73 struct adb_request req;
74 int level = bd->props.brightness;
75
76
77 if (bd->props.power != FB_BLANK_UNBLANK ||
78 bd->props.fb_blank != FB_BLANK_UNBLANK)
79 level = 0;
80
81 if (level > 0) {
82 int pmulevel = pmu_backlight_get_level_brightness(level);
83
84 pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
85 pmu_wait_complete(&req);
86
87 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
88 PMU_POW_BACKLIGHT | PMU_POW_ON);
89 pmu_wait_complete(&req);
90 } else {
91 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
92 PMU_POW_BACKLIGHT | PMU_POW_OFF);
93 pmu_wait_complete(&req);
94 }
95
96 return 0;
97 }
98
pmu_backlight_update_status(struct backlight_device * bd)99 static int pmu_backlight_update_status(struct backlight_device *bd)
100 {
101 unsigned long flags;
102 int rc = 0;
103
104 spin_lock_irqsave(&pmu_backlight_lock, flags);
105 /* Don't update brightness when sleeping */
106 if (!sleeping)
107 rc = __pmu_backlight_update_status(bd);
108 spin_unlock_irqrestore(&pmu_backlight_lock, flags);
109 return rc;
110 }
111
112
pmu_backlight_get_brightness(struct backlight_device * bd)113 static int pmu_backlight_get_brightness(struct backlight_device *bd)
114 {
115 return bd->props.brightness;
116 }
117
118 static const struct backlight_ops pmu_backlight_data = {
119 .get_brightness = pmu_backlight_get_brightness,
120 .update_status = pmu_backlight_update_status,
121
122 };
123
124 #ifdef CONFIG_PM
pmu_backlight_set_sleep(int sleep)125 void pmu_backlight_set_sleep(int sleep)
126 {
127 unsigned long flags;
128
129 spin_lock_irqsave(&pmu_backlight_lock, flags);
130 sleeping = sleep;
131 if (pmac_backlight && uses_pmu_bl) {
132 if (sleep) {
133 struct adb_request req;
134
135 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
136 PMU_POW_BACKLIGHT | PMU_POW_OFF);
137 pmu_wait_complete(&req);
138 } else
139 __pmu_backlight_update_status(pmac_backlight);
140 }
141 spin_unlock_irqrestore(&pmu_backlight_lock, flags);
142 }
143 #endif /* CONFIG_PM */
144
pmu_backlight_init()145 void __init pmu_backlight_init()
146 {
147 struct backlight_properties props;
148 struct backlight_device *bd;
149 char name[10];
150 int level, autosave;
151
152 /* Special case for the old PowerBook since I can't test on it */
153 autosave =
154 of_machine_is_compatible("AAPL,3400/2400") ||
155 of_machine_is_compatible("AAPL,3500");
156
157 if (!autosave &&
158 !pmac_has_backlight_type("pmu") &&
159 !of_machine_is_compatible("AAPL,PowerBook1998") &&
160 !of_machine_is_compatible("PowerBook1,1"))
161 return;
162
163 snprintf(name, sizeof(name), "pmubl");
164
165 memset(&props, 0, sizeof(struct backlight_properties));
166 props.type = BACKLIGHT_PLATFORM;
167 props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
168 bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
169 &props);
170 if (IS_ERR(bd)) {
171 printk(KERN_ERR "PMU Backlight registration failed\n");
172 return;
173 }
174 uses_pmu_bl = 1;
175 pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
176
177 level = bd->props.max_brightness;
178
179 if (autosave) {
180 /* read autosaved value if available */
181 struct adb_request req;
182 pmu_request(&req, NULL, 2, 0xd9, 0);
183 pmu_wait_complete(&req);
184
185 level = pmu_backlight_curve_lookup(
186 (req.reply[0] >> 4) *
187 bd->props.max_brightness / 15);
188 }
189
190 bd->props.brightness = level;
191 bd->props.power = FB_BLANK_UNBLANK;
192 backlight_update_status(bd);
193
194 printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
195 }
196