1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Backlight code for via-pmu |
4 | * |
5 | * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi. |
6 | * Copyright (C) 2001-2002 Benjamin Herrenschmidt |
7 | * Copyright (C) 2006 Michael Hanselmann <linux-kernel@hansmi.ch> |
8 | * |
9 | */ |
10 | |
11 | #include <asm/ptrace.h> |
12 | #include <linux/adb.h> |
13 | #include <linux/pmu.h> |
14 | #include <asm/backlight.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 = backlight_get_brightness(bd); |
75 | |
76 | if (level > 0) { |
77 | int pmulevel = pmu_backlight_get_level_brightness(level); |
78 | |
79 | pmu_request(req: &req, NULL, nbytes: 2, PMU_BACKLIGHT_BRIGHT, pmulevel); |
80 | pmu_wait_complete(req: &req); |
81 | |
82 | pmu_request(req: &req, NULL, nbytes: 2, PMU_POWER_CTRL, |
83 | PMU_POW_BACKLIGHT | PMU_POW_ON); |
84 | pmu_wait_complete(req: &req); |
85 | } else { |
86 | pmu_request(req: &req, NULL, nbytes: 2, PMU_POWER_CTRL, |
87 | PMU_POW_BACKLIGHT | PMU_POW_OFF); |
88 | pmu_wait_complete(req: &req); |
89 | } |
90 | |
91 | return 0; |
92 | } |
93 | |
94 | static int pmu_backlight_update_status(struct backlight_device *bd) |
95 | { |
96 | unsigned long flags; |
97 | int rc = 0; |
98 | |
99 | spin_lock_irqsave(&pmu_backlight_lock, flags); |
100 | /* Don't update brightness when sleeping */ |
101 | if (!sleeping) |
102 | rc = __pmu_backlight_update_status(bd); |
103 | spin_unlock_irqrestore(lock: &pmu_backlight_lock, flags); |
104 | return rc; |
105 | } |
106 | |
107 | |
108 | static const struct backlight_ops pmu_backlight_data = { |
109 | .update_status = pmu_backlight_update_status, |
110 | |
111 | }; |
112 | |
113 | #ifdef CONFIG_PM |
114 | void pmu_backlight_set_sleep(int sleep) |
115 | { |
116 | unsigned long flags; |
117 | |
118 | spin_lock_irqsave(&pmu_backlight_lock, flags); |
119 | sleeping = sleep; |
120 | if (pmac_backlight && uses_pmu_bl) { |
121 | if (sleep) { |
122 | struct adb_request req; |
123 | |
124 | pmu_request(req: &req, NULL, nbytes: 2, PMU_POWER_CTRL, |
125 | PMU_POW_BACKLIGHT | PMU_POW_OFF); |
126 | pmu_wait_complete(req: &req); |
127 | } else |
128 | __pmu_backlight_update_status(bd: pmac_backlight); |
129 | } |
130 | spin_unlock_irqrestore(lock: &pmu_backlight_lock, flags); |
131 | } |
132 | #endif /* CONFIG_PM */ |
133 | |
134 | void __init pmu_backlight_init(void) |
135 | { |
136 | struct backlight_properties props; |
137 | struct backlight_device *bd; |
138 | char name[10]; |
139 | int level, autosave; |
140 | |
141 | /* Special case for the old PowerBook since I can't test on it */ |
142 | autosave = |
143 | of_machine_is_compatible("AAPL,3400/2400" ) || |
144 | of_machine_is_compatible("AAPL,3500" ); |
145 | |
146 | if (!autosave && |
147 | !pmac_has_backlight_type("pmu" ) && |
148 | !of_machine_is_compatible("AAPL,PowerBook1998" ) && |
149 | !of_machine_is_compatible("PowerBook1,1" )) |
150 | return; |
151 | |
152 | snprintf(buf: name, size: sizeof(name), fmt: "pmubl" ); |
153 | |
154 | memset(&props, 0, sizeof(struct backlight_properties)); |
155 | props.type = BACKLIGHT_PLATFORM; |
156 | props.max_brightness = FB_BACKLIGHT_LEVELS - 1; |
157 | bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data, |
158 | &props); |
159 | if (IS_ERR(ptr: bd)) { |
160 | printk(KERN_ERR "PMU Backlight registration failed\n" ); |
161 | return; |
162 | } |
163 | uses_pmu_bl = 1; |
164 | pmu_backlight_init_curve(off: 0x7F, min: 0x46, max: 0x0E); |
165 | |
166 | level = bd->props.max_brightness; |
167 | |
168 | if (autosave) { |
169 | /* read autosaved value if available */ |
170 | struct adb_request req; |
171 | pmu_request(req: &req, NULL, nbytes: 2, 0xd9, 0); |
172 | pmu_wait_complete(req: &req); |
173 | |
174 | level = pmu_backlight_curve_lookup( |
175 | value: (req.reply[0] >> 4) * |
176 | bd->props.max_brightness / 15); |
177 | } |
178 | |
179 | bd->props.brightness = level; |
180 | bd->props.power = FB_BLANK_UNBLANK; |
181 | backlight_update_status(bd); |
182 | |
183 | printk(KERN_INFO "PMU Backlight initialized (%s)\n" , name); |
184 | } |
185 | |