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
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 = backlight_get_brightness(bd);
75
76 if (level > 0) {
77 int pmulevel = pmu_backlight_get_level_brightness(level);
78
79 pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
80 pmu_wait_complete(&req);
81
82 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
83 PMU_POW_BACKLIGHT | PMU_POW_ON);
84 pmu_wait_complete(&req);
85 } else {
86 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
87 PMU_POW_BACKLIGHT | PMU_POW_OFF);
88 pmu_wait_complete(&req);
89 }
90
91 return 0;
92 }
93
pmu_backlight_update_status(struct backlight_device * bd)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(&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
pmu_backlight_set_sleep(int sleep)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, NULL, 2, PMU_POWER_CTRL,
125 PMU_POW_BACKLIGHT | PMU_POW_OFF);
126 pmu_wait_complete(&req);
127 } else
128 __pmu_backlight_update_status(pmac_backlight);
129 }
130 spin_unlock_irqrestore(&pmu_backlight_lock, flags);
131 }
132 #endif /* CONFIG_PM */
133
pmu_backlight_init(void)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(name, sizeof(name), "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(bd)) {
160 printk(KERN_ERR "PMU Backlight registration failed\n");
161 return;
162 }
163 uses_pmu_bl = 1;
164 pmu_backlight_init_curve(0x7F, 0x46, 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, NULL, 2, 0xd9, 0);
172 pmu_wait_complete(&req);
173
174 level = pmu_backlight_curve_lookup(
175 (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