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