1/*
2 * Backlight code for via-pmu
3 *
4 * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
5 * Copyright (C) 2001-2002 Benjamin Herrenschmidt
6 * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>
7 *
8 */
9
10#include <asm/ptrace.h>
11#include <linux/adb.h>
12#include <linux/pmu.h>
13#include <asm/backlight.h>
14#include <asm/prom.h>
15
16#define MAX_PMU_LEVEL 0xFF
17
18static const struct backlight_ops pmu_backlight_data;
19static DEFINE_SPINLOCK(pmu_backlight_lock);
20static int sleeping, uses_pmu_bl;
21static u8 bl_curve[FB_BACKLIGHT_LEVELS];
22
23static 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
37static 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
57static 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
71static int __pmu_backlight_update_status(struct backlight_device *bd)
72{
73	struct adb_request req;
74	int level = bd->props.brightness;
75
76
77	if (bd->props.power != FB_BLANK_UNBLANK ||
78	    bd->props.fb_blank != FB_BLANK_UNBLANK)
79		level = 0;
80
81	if (level > 0) {
82		int pmulevel = pmu_backlight_get_level_brightness(level);
83
84		pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
85		pmu_wait_complete(&req);
86
87		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
88			PMU_POW_BACKLIGHT | PMU_POW_ON);
89		pmu_wait_complete(&req);
90	} else {
91		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
92			PMU_POW_BACKLIGHT | PMU_POW_OFF);
93		pmu_wait_complete(&req);
94	}
95
96	return 0;
97}
98
99static int pmu_backlight_update_status(struct backlight_device *bd)
100{
101	unsigned long flags;
102	int rc = 0;
103
104	spin_lock_irqsave(&pmu_backlight_lock, flags);
105	/* Don't update brightness when sleeping */
106	if (!sleeping)
107		rc = __pmu_backlight_update_status(bd);
108	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
109	return rc;
110}
111
112
113static const struct backlight_ops pmu_backlight_data = {
114	.update_status	= pmu_backlight_update_status,
115
116};
117
118#ifdef CONFIG_PM
119void pmu_backlight_set_sleep(int sleep)
120{
121	unsigned long flags;
122
123	spin_lock_irqsave(&pmu_backlight_lock, flags);
124	sleeping = sleep;
125	if (pmac_backlight && uses_pmu_bl) {
126		if (sleep) {
127			struct adb_request req;
128
129			pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
130				    PMU_POW_BACKLIGHT | PMU_POW_OFF);
131			pmu_wait_complete(&req);
132		} else
133			__pmu_backlight_update_status(pmac_backlight);
134	}
135	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
136}
137#endif /* CONFIG_PM */
138
139void __init pmu_backlight_init()
140{
141	struct backlight_properties props;
142	struct backlight_device *bd;
143	char name[10];
144	int level, autosave;
145
146	/* Special case for the old PowerBook since I can't test on it */
147	autosave =
148		of_machine_is_compatible("AAPL,3400/2400") ||
149		of_machine_is_compatible("AAPL,3500");
150
151	if (!autosave &&
152	    !pmac_has_backlight_type("pmu") &&
153	    !of_machine_is_compatible("AAPL,PowerBook1998") &&
154	    !of_machine_is_compatible("PowerBook1,1"))
155		return;
156
157	snprintf(name, sizeof(name), "pmubl");
158
159	memset(&props, 0, sizeof(struct backlight_properties));
160	props.type = BACKLIGHT_PLATFORM;
161	props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
162	bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
163				       &props);
164	if (IS_ERR(bd)) {
165		printk(KERN_ERR "PMU Backlight registration failed\n");
166		return;
167	}
168	uses_pmu_bl = 1;
169	pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
170
171	level = bd->props.max_brightness;
172
173	if (autosave) {
174		/* read autosaved value if available */
175		struct adb_request req;
176		pmu_request(&req, NULL, 2, 0xd9, 0);
177		pmu_wait_complete(&req);
178
179		level = pmu_backlight_curve_lookup(
180				(req.reply[0] >> 4) *
181				bd->props.max_brightness / 15);
182	}
183
184	bd->props.brightness = level;
185	bd->props.power = FB_BLANK_UNBLANK;
186	backlight_update_status(bd);
187
188	printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
189}
190