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/fb.h>
15 #include <linux/of.h>
16 #include <linux/pmu.h>
17 #include <asm/backlight.h>
18
19 #define MAX_PMU_LEVEL 0xFF
20
21 static const struct backlight_ops pmu_backlight_data;
22 static DEFINE_SPINLOCK(pmu_backlight_lock);
23 static int sleeping, uses_pmu_bl;
24 static u8 bl_curve[FB_BACKLIGHT_LEVELS];
25
pmu_backlight_init_curve(u8 off,u8 min,u8 max)26 static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
27 {
28 int i, flat, count, range = (max - min);
29
30 bl_curve[0] = off;
31
32 for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
33 bl_curve[flat] = min;
34
35 count = FB_BACKLIGHT_LEVELS * 15 / 16;
36 for (i = 0; i < count; ++i)
37 bl_curve[flat + i] = min + (range * (i + 1) / count);
38 }
39
pmu_backlight_curve_lookup(int value)40 static int pmu_backlight_curve_lookup(int value)
41 {
42 int level = (FB_BACKLIGHT_LEVELS - 1);
43 int i, max = 0;
44
45 /* Look for biggest value */
46 for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
47 max = max((int)bl_curve[i], max);
48
49 /* Look for nearest value */
50 for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
51 int diff = abs(bl_curve[i] - value);
52 if (diff < max) {
53 max = diff;
54 level = i;
55 }
56 }
57 return level;
58 }
59
pmu_backlight_get_level_brightness(int level)60 static int pmu_backlight_get_level_brightness(int level)
61 {
62 int pmulevel;
63
64 /* Get and convert the value */
65 pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;
66 if (pmulevel < 0)
67 pmulevel = 0;
68 else if (pmulevel > MAX_PMU_LEVEL)
69 pmulevel = MAX_PMU_LEVEL;
70
71 return pmulevel;
72 }
73
__pmu_backlight_update_status(struct backlight_device * bd)74 static int __pmu_backlight_update_status(struct backlight_device *bd)
75 {
76 struct adb_request req;
77 int level = backlight_get_brightness(bd);
78
79 if (level > 0) {
80 int pmulevel = pmu_backlight_get_level_brightness(level);
81
82 pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
83 pmu_wait_complete(&req);
84
85 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
86 PMU_POW_BACKLIGHT | PMU_POW_ON);
87 pmu_wait_complete(&req);
88 } else {
89 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
90 PMU_POW_BACKLIGHT | PMU_POW_OFF);
91 pmu_wait_complete(&req);
92 }
93
94 return 0;
95 }
96
pmu_backlight_update_status(struct backlight_device * bd)97 static int pmu_backlight_update_status(struct backlight_device *bd)
98 {
99 unsigned long flags;
100 int rc = 0;
101
102 spin_lock_irqsave(&pmu_backlight_lock, flags);
103 /* Don't update brightness when sleeping */
104 if (!sleeping)
105 rc = __pmu_backlight_update_status(bd);
106 spin_unlock_irqrestore(&pmu_backlight_lock, flags);
107 return rc;
108 }
109
110
111 static const struct backlight_ops pmu_backlight_data = {
112 .update_status = pmu_backlight_update_status,
113
114 };
115
116 #ifdef CONFIG_PM
pmu_backlight_set_sleep(int sleep)117 void pmu_backlight_set_sleep(int sleep)
118 {
119 unsigned long flags;
120
121 spin_lock_irqsave(&pmu_backlight_lock, flags);
122 sleeping = sleep;
123 if (pmac_backlight && uses_pmu_bl) {
124 if (sleep) {
125 struct adb_request req;
126
127 pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
128 PMU_POW_BACKLIGHT | PMU_POW_OFF);
129 pmu_wait_complete(&req);
130 } else
131 __pmu_backlight_update_status(pmac_backlight);
132 }
133 spin_unlock_irqrestore(&pmu_backlight_lock, flags);
134 }
135 #endif /* CONFIG_PM */
136
pmu_backlight_init(void)137 void __init pmu_backlight_init(void)
138 {
139 struct backlight_properties props;
140 struct backlight_device *bd;
141 char name[10];
142 int level, autosave;
143
144 /* Special case for the old PowerBook since I can't test on it */
145 autosave =
146 of_machine_is_compatible("AAPL,3400/2400") ||
147 of_machine_is_compatible("AAPL,3500");
148
149 if (!autosave &&
150 !pmac_has_backlight_type("pmu") &&
151 !of_machine_is_compatible("AAPL,PowerBook1998") &&
152 !of_machine_is_compatible("PowerBook1,1"))
153 return;
154
155 snprintf(name, sizeof(name), "pmubl");
156
157 memset(&props, 0, sizeof(struct backlight_properties));
158 props.type = BACKLIGHT_PLATFORM;
159 props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
160 bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
161 &props);
162 if (IS_ERR(bd)) {
163 printk(KERN_ERR "PMU Backlight registration failed\n");
164 return;
165 }
166 uses_pmu_bl = 1;
167 pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
168
169 level = bd->props.max_brightness;
170
171 if (autosave) {
172 /* read autosaved value if available */
173 struct adb_request req;
174 pmu_request(&req, NULL, 2, 0xd9, 0);
175 pmu_wait_complete(&req);
176
177 level = pmu_backlight_curve_lookup(
178 (req.reply[0] >> 4) *
179 bd->props.max_brightness / 15);
180 }
181
182 bd->props.brightness = level;
183 bd->props.power = BACKLIGHT_POWER_ON;
184 backlight_update_status(bd);
185
186 printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
187 }
188