Root/drivers/macintosh/via-pmu-backlight.c

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 int pmu_backlight_get_brightness(struct backlight_device *bd)
114{
115    return bd->props.brightness;
116}
117
118static const struct backlight_ops pmu_backlight_data = {
119    .get_brightness = pmu_backlight_get_brightness,
120    .update_status = pmu_backlight_update_status,
121
122};
123
124#ifdef CONFIG_PM
125void pmu_backlight_set_sleep(int sleep)
126{
127    unsigned long flags;
128
129    spin_lock_irqsave(&pmu_backlight_lock, flags);
130    sleeping = sleep;
131    if (pmac_backlight && uses_pmu_bl) {
132        if (sleep) {
133            struct adb_request req;
134
135            pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
136                    PMU_POW_BACKLIGHT | PMU_POW_OFF);
137            pmu_wait_complete(&req);
138        } else
139            __pmu_backlight_update_status(pmac_backlight);
140    }
141    spin_unlock_irqrestore(&pmu_backlight_lock, flags);
142}
143#endif /* CONFIG_PM */
144
145void __init pmu_backlight_init()
146{
147    struct backlight_properties props;
148    struct backlight_device *bd;
149    char name[10];
150    int level, autosave;
151
152    /* Special case for the old PowerBook since I can't test on it */
153    autosave =
154        of_machine_is_compatible("AAPL,3400/2400") ||
155        of_machine_is_compatible("AAPL,3500");
156
157    if (!autosave &&
158        !pmac_has_backlight_type("pmu") &&
159        !of_machine_is_compatible("AAPL,PowerBook1998") &&
160        !of_machine_is_compatible("PowerBook1,1"))
161        return;
162
163    snprintf(name, sizeof(name), "pmubl");
164
165    memset(&props, 0, sizeof(struct backlight_properties));
166    props.type = BACKLIGHT_PLATFORM;
167    props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
168    bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
169                       &props);
170    if (IS_ERR(bd)) {
171        printk(KERN_ERR "PMU Backlight registration failed\n");
172        return;
173    }
174    uses_pmu_bl = 1;
175    pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
176
177    level = bd->props.max_brightness;
178
179    if (autosave) {
180        /* read autosaved value if available */
181        struct adb_request req;
182        pmu_request(&req, NULL, 2, 0xd9, 0);
183        pmu_wait_complete(&req);
184
185        level = pmu_backlight_curve_lookup(
186                (req.reply[0] >> 4) *
187                bd->props.max_brightness / 15);
188    }
189
190    bd->props.brightness = level;
191    bd->props.power = FB_BLANK_UNBLANK;
192    backlight_update_status(bd);
193
194    printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
195}
196

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