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, 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 
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
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 
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