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 
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 
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 	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 
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 
113 static const struct backlight_ops pmu_backlight_data = {
114 	.update_status	= pmu_backlight_update_status,
115 
116 };
117 
118 #ifdef CONFIG_PM
119 void pmu_backlight_set_sleep(int sleep)
120 {
121 	unsigned long flags;
122 
123 	spin_lock_irqsave(&pmu_backlight_lock, flags);
124 	sleeping = sleep;
125 	if (pmac_backlight && uses_pmu_bl) {
126 		if (sleep) {
127 			struct adb_request req;
128 
129 			pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
130 				    PMU_POW_BACKLIGHT | PMU_POW_OFF);
131 			pmu_wait_complete(&req);
132 		} else
133 			__pmu_backlight_update_status(pmac_backlight);
134 	}
135 	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
136 }
137 #endif /* CONFIG_PM */
138 
139 void __init pmu_backlight_init()
140 {
141 	struct backlight_properties props;
142 	struct backlight_device *bd;
143 	char name[10];
144 	int level, autosave;
145 
146 	/* Special case for the old PowerBook since I can't test on it */
147 	autosave =
148 		of_machine_is_compatible("AAPL,3400/2400") ||
149 		of_machine_is_compatible("AAPL,3500");
150 
151 	if (!autosave &&
152 	    !pmac_has_backlight_type("pmu") &&
153 	    !of_machine_is_compatible("AAPL,PowerBook1998") &&
154 	    !of_machine_is_compatible("PowerBook1,1"))
155 		return;
156 
157 	snprintf(name, sizeof(name), "pmubl");
158 
159 	memset(&props, 0, sizeof(struct backlight_properties));
160 	props.type = BACKLIGHT_PLATFORM;
161 	props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
162 	bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
163 				       &props);
164 	if (IS_ERR(bd)) {
165 		printk(KERN_ERR "PMU Backlight registration failed\n");
166 		return;
167 	}
168 	uses_pmu_bl = 1;
169 	pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
170 
171 	level = bd->props.max_brightness;
172 
173 	if (autosave) {
174 		/* read autosaved value if available */
175 		struct adb_request req;
176 		pmu_request(&req, NULL, 2, 0xd9, 0);
177 		pmu_wait_complete(&req);
178 
179 		level = pmu_backlight_curve_lookup(
180 				(req.reply[0] >> 4) *
181 				bd->props.max_brightness / 15);
182 	}
183 
184 	bd->props.brightness = level;
185 	bd->props.power = FB_BLANK_UNBLANK;
186 	backlight_update_status(bd);
187 
188 	printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
189 }
190