1 /*
2 * Miscellaneous procedures for dealing with the PowerMac hardware.
3 * Contains support for the backlight.
4 *
5 * Copyright (C) 2000 Benjamin Herrenschmidt
6 * Copyright (C) 2006 Michael Hanselmann <linux-kernel@hansmi.ch>
7 *
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/fb.h>
12 #include <linux/backlight.h>
13 #include <linux/adb.h>
14 #include <linux/pmu.h>
15 #include <asm/atomic.h>
16 #include <asm/prom.h>
17 #include <asm/backlight.h>
18
19 #define OLD_BACKLIGHT_MAX 15
20
21 static void pmac_backlight_key_worker(struct work_struct *work);
22 static void pmac_backlight_set_legacy_worker(struct work_struct *work);
23
24 static DECLARE_WORK(pmac_backlight_key_work, pmac_backlight_key_worker);
25 static DECLARE_WORK(pmac_backlight_set_legacy_work, pmac_backlight_set_legacy_worker);
26
27 /* Although these variables are used in interrupt context, it makes no sense to
28 * protect them. No user is able to produce enough key events per second and
29 * notice the errors that might happen.
30 */
31 static int pmac_backlight_key_queued;
32 static int pmac_backlight_set_legacy_queued;
33
34 /* The via-pmu code allows the backlight to be grabbed, in which case the
35 * in-kernel control of the brightness needs to be disabled. This should
36 * only be used by really old PowerBooks.
37 */
38 static atomic_t kernel_backlight_disabled = ATOMIC_INIT(0);
39
40 /* Protect the pmac_backlight variable below.
41 You should hold this lock when using the pmac_backlight pointer to
42 prevent its potential removal. */
43 DEFINE_MUTEX(pmac_backlight_mutex);
44
45 /* Main backlight storage
46 *
47 * Backlight drivers in this variable are required to have the "ops"
48 * attribute set and to have an update_status function.
49 *
50 * We can only store one backlight here, but since Apple laptops have only one
51 * internal display, it doesn't matter. Other backlight drivers can be used
52 * independently.
53 *
54 */
55 struct backlight_device *pmac_backlight;
56
pmac_has_backlight_type(const char * type)57 int pmac_has_backlight_type(const char *type)
58 {
59 struct device_node* bk_node = of_find_node_by_name(NULL, "backlight");
60
61 if (bk_node) {
62 const char *prop = of_get_property(bk_node,
63 "backlight-control", NULL);
64 if (prop && strncmp(prop, type, strlen(type)) == 0) {
65 of_node_put(bk_node);
66 return 1;
67 }
68 of_node_put(bk_node);
69 }
70
71 return 0;
72 }
73
pmac_backlight_curve_lookup(struct fb_info * info,int value)74 int pmac_backlight_curve_lookup(struct fb_info *info, int value)
75 {
76 int level = (FB_BACKLIGHT_LEVELS - 1);
77
78 if (info && info->bl_dev) {
79 int i, max = 0;
80
81 /* Look for biggest value */
82 for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
83 max = max((int)info->bl_curve[i], max);
84
85 /* Look for nearest value */
86 for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
87 int diff = abs(info->bl_curve[i] - value);
88 if (diff < max) {
89 max = diff;
90 level = i;
91 }
92 }
93
94 }
95
96 return level;
97 }
98
pmac_backlight_key_worker(struct work_struct * work)99 static void pmac_backlight_key_worker(struct work_struct *work)
100 {
101 if (atomic_read(&kernel_backlight_disabled))
102 return;
103
104 mutex_lock(&pmac_backlight_mutex);
105 if (pmac_backlight) {
106 struct backlight_properties *props;
107 int brightness;
108
109 props = &pmac_backlight->props;
110
111 brightness = props->brightness +
112 ((pmac_backlight_key_queued?-1:1) *
113 (props->max_brightness / 15));
114
115 if (brightness < 0)
116 brightness = 0;
117 else if (brightness > props->max_brightness)
118 brightness = props->max_brightness;
119
120 props->brightness = brightness;
121 backlight_update_status(pmac_backlight);
122 }
123 mutex_unlock(&pmac_backlight_mutex);
124 }
125
126 /* This function is called in interrupt context */
pmac_backlight_key(int direction)127 void pmac_backlight_key(int direction)
128 {
129 if (atomic_read(&kernel_backlight_disabled))
130 return;
131
132 /* we can receive multiple interrupts here, but the scheduled work
133 * will run only once, with the last value
134 */
135 pmac_backlight_key_queued = direction;
136 schedule_work(&pmac_backlight_key_work);
137 }
138
__pmac_backlight_set_legacy_brightness(int brightness)139 static int __pmac_backlight_set_legacy_brightness(int brightness)
140 {
141 int error = -ENXIO;
142
143 mutex_lock(&pmac_backlight_mutex);
144 if (pmac_backlight) {
145 struct backlight_properties *props;
146
147 props = &pmac_backlight->props;
148 props->brightness = brightness *
149 (props->max_brightness + 1) /
150 (OLD_BACKLIGHT_MAX + 1);
151
152 if (props->brightness > props->max_brightness)
153 props->brightness = props->max_brightness;
154 else if (props->brightness < 0)
155 props->brightness = 0;
156
157 backlight_update_status(pmac_backlight);
158
159 error = 0;
160 }
161 mutex_unlock(&pmac_backlight_mutex);
162
163 return error;
164 }
165
pmac_backlight_set_legacy_worker(struct work_struct * work)166 static void pmac_backlight_set_legacy_worker(struct work_struct *work)
167 {
168 if (atomic_read(&kernel_backlight_disabled))
169 return;
170
171 __pmac_backlight_set_legacy_brightness(pmac_backlight_set_legacy_queued);
172 }
173
174 /* This function is called in interrupt context */
pmac_backlight_set_legacy_brightness_pmu(int brightness)175 void pmac_backlight_set_legacy_brightness_pmu(int brightness) {
176 if (atomic_read(&kernel_backlight_disabled))
177 return;
178
179 pmac_backlight_set_legacy_queued = brightness;
180 schedule_work(&pmac_backlight_set_legacy_work);
181 }
182
pmac_backlight_set_legacy_brightness(int brightness)183 int pmac_backlight_set_legacy_brightness(int brightness)
184 {
185 return __pmac_backlight_set_legacy_brightness(brightness);
186 }
187
pmac_backlight_get_legacy_brightness()188 int pmac_backlight_get_legacy_brightness()
189 {
190 int result = -ENXIO;
191
192 mutex_lock(&pmac_backlight_mutex);
193 if (pmac_backlight) {
194 struct backlight_properties *props;
195
196 props = &pmac_backlight->props;
197
198 result = props->brightness *
199 (OLD_BACKLIGHT_MAX + 1) /
200 (props->max_brightness + 1);
201 }
202 mutex_unlock(&pmac_backlight_mutex);
203
204 return result;
205 }
206
pmac_backlight_disable()207 void pmac_backlight_disable()
208 {
209 atomic_inc(&kernel_backlight_disabled);
210 }
211
pmac_backlight_enable()212 void pmac_backlight_enable()
213 {
214 atomic_dec(&kernel_backlight_disabled);
215 }
216
217 EXPORT_SYMBOL_GPL(pmac_backlight);
218 EXPORT_SYMBOL_GPL(pmac_backlight_mutex);
219 EXPORT_SYMBOL_GPL(pmac_has_backlight_type);
220