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/backlight.h> |
14 | #include <linux/pmu.h> |
15 | #include <asm/backlight.h> |
16 | |
17 | #define MAX_PMU_LEVEL 0xFF |
18 | |
19 | static const struct backlight_ops pmu_backlight_data; |
20 | static DEFINE_SPINLOCK(pmu_backlight_lock); |
21 | static int sleeping, uses_pmu_bl; |
22 | static u8 bl_curve[FB_BACKLIGHT_LEVELS]; |
23 | |
24 | static void pmu_backlight_init_curve(u8 off, u8 min, u8 max) |
25 | { |
26 | int i, flat, count, range = (max - min); |
27 | |
28 | bl_curve[0] = off; |
29 | |
30 | for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat) |
31 | bl_curve[flat] = min; |
32 | |
33 | count = FB_BACKLIGHT_LEVELS * 15 / 16; |
34 | for (i = 0; i < count; ++i) |
35 | bl_curve[flat + i] = min + (range * (i + 1) / count); |
36 | } |
37 | |
38 | static int pmu_backlight_curve_lookup(int value) |
39 | { |
40 | int level = (FB_BACKLIGHT_LEVELS - 1); |
41 | int i, max = 0; |
42 | |
43 | /* Look for biggest value */ |
44 | for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) |
45 | max = max((int)bl_curve[i], max); |
46 | |
47 | /* Look for nearest value */ |
48 | for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) { |
49 | int diff = abs(bl_curve[i] - value); |
50 | if (diff < max) { |
51 | max = diff; |
52 | level = i; |
53 | } |
54 | } |
55 | return level; |
56 | } |
57 | |
58 | static int pmu_backlight_get_level_brightness(int level) |
59 | { |
60 | int pmulevel; |
61 | |
62 | /* Get and convert the value */ |
63 | pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL; |
64 | if (pmulevel < 0) |
65 | pmulevel = 0; |
66 | else if (pmulevel > MAX_PMU_LEVEL) |
67 | pmulevel = MAX_PMU_LEVEL; |
68 | |
69 | return pmulevel; |
70 | } |
71 | |
72 | static int __pmu_backlight_update_status(struct backlight_device *bd) |
73 | { |
74 | struct adb_request req; |
75 | int level = backlight_get_brightness(bd); |
76 | |
77 | if (level > 0) { |
78 | int pmulevel = pmu_backlight_get_level_brightness(level); |
79 | |
80 | pmu_request(req: &req, NULL, nbytes: 2, PMU_BACKLIGHT_BRIGHT, pmulevel); |
81 | pmu_wait_complete(req: &req); |
82 | |
83 | pmu_request(req: &req, NULL, nbytes: 2, PMU_POWER_CTRL, |
84 | PMU_POW_BACKLIGHT | PMU_POW_ON); |
85 | pmu_wait_complete(req: &req); |
86 | } else { |
87 | pmu_request(req: &req, NULL, nbytes: 2, PMU_POWER_CTRL, |
88 | PMU_POW_BACKLIGHT | PMU_POW_OFF); |
89 | pmu_wait_complete(req: &req); |
90 | } |
91 | |
92 | return 0; |
93 | } |
94 | |
95 | static int pmu_backlight_update_status(struct backlight_device *bd) |
96 | { |
97 | unsigned long flags; |
98 | int rc = 0; |
99 | |
100 | spin_lock_irqsave(&pmu_backlight_lock, flags); |
101 | /* Don't update brightness when sleeping */ |
102 | if (!sleeping) |
103 | rc = __pmu_backlight_update_status(bd); |
104 | spin_unlock_irqrestore(lock: &pmu_backlight_lock, flags); |
105 | return rc; |
106 | } |
107 | |
108 | |
109 | static const struct backlight_ops pmu_backlight_data = { |
110 | .update_status = pmu_backlight_update_status, |
111 | |
112 | }; |
113 | |
114 | #ifdef CONFIG_PM |
115 | void pmu_backlight_set_sleep(int sleep) |
116 | { |
117 | unsigned long flags; |
118 | |
119 | spin_lock_irqsave(&pmu_backlight_lock, flags); |
120 | sleeping = sleep; |
121 | if (pmac_backlight && uses_pmu_bl) { |
122 | if (sleep) { |
123 | struct adb_request req; |
124 | |
125 | pmu_request(req: &req, NULL, nbytes: 2, PMU_POWER_CTRL, |
126 | PMU_POW_BACKLIGHT | PMU_POW_OFF); |
127 | pmu_wait_complete(req: &req); |
128 | } else |
129 | __pmu_backlight_update_status(bd: pmac_backlight); |
130 | } |
131 | spin_unlock_irqrestore(lock: &pmu_backlight_lock, flags); |
132 | } |
133 | #endif /* CONFIG_PM */ |
134 | |
135 | void __init pmu_backlight_init(void) |
136 | { |
137 | struct backlight_properties props; |
138 | struct backlight_device *bd; |
139 | char name[10]; |
140 | int level, autosave; |
141 | |
142 | /* Special case for the old PowerBook since I can't test on it */ |
143 | autosave = |
144 | of_machine_is_compatible(compat: "AAPL,3400/2400" ) || |
145 | of_machine_is_compatible(compat: "AAPL,3500" ); |
146 | |
147 | if (!autosave && |
148 | !pmac_has_backlight_type("pmu" ) && |
149 | !of_machine_is_compatible(compat: "AAPL,PowerBook1998" ) && |
150 | !of_machine_is_compatible(compat: "PowerBook1,1" )) |
151 | return; |
152 | |
153 | snprintf(buf: name, size: sizeof(name), fmt: "pmubl" ); |
154 | |
155 | memset(&props, 0, sizeof(struct backlight_properties)); |
156 | props.type = BACKLIGHT_PLATFORM; |
157 | props.max_brightness = FB_BACKLIGHT_LEVELS - 1; |
158 | bd = backlight_device_register(name, NULL, NULL, ops: &pmu_backlight_data, |
159 | props: &props); |
160 | if (IS_ERR(ptr: bd)) { |
161 | printk(KERN_ERR "PMU Backlight registration failed\n" ); |
162 | return; |
163 | } |
164 | uses_pmu_bl = 1; |
165 | pmu_backlight_init_curve(off: 0x7F, min: 0x46, max: 0x0E); |
166 | |
167 | level = bd->props.max_brightness; |
168 | |
169 | if (autosave) { |
170 | /* read autosaved value if available */ |
171 | struct adb_request req; |
172 | pmu_request(req: &req, NULL, nbytes: 2, 0xd9, 0); |
173 | pmu_wait_complete(req: &req); |
174 | |
175 | level = pmu_backlight_curve_lookup( |
176 | value: (req.reply[0] >> 4) * |
177 | bd->props.max_brightness / 15); |
178 | } |
179 | |
180 | bd->props.brightness = level; |
181 | bd->props.power = FB_BLANK_UNBLANK; |
182 | backlight_update_status(bd); |
183 | |
184 | printk(KERN_INFO "PMU Backlight initialized (%s)\n" , name); |
185 | } |
186 | |