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