2 * Miscellaneous procedures for dealing with the PowerMac hardware.
3 * Contains support for the backlight.
5 * Copyright (C) 2000 Benjamin Herrenschmidt
6 * Copyright (C) 2006 Michael Hanselmann <linux-kernel@hansmi.ch>
10 #include <linux/kernel.h>
12 #include <linux/backlight.h>
13 #include <linux/adb.h>
14 #include <linux/pmu.h>
15 #include <asm/atomic.h>
17 #include <asm/backlight.h>
19 #define OLD_BACKLIGHT_MAX 15
21 static void pmac_backlight_key_worker(void *data
);
22 static void pmac_backlight_set_legacy_worker(void *data
);
24 static DECLARE_WORK(pmac_backlight_key_work
, pmac_backlight_key_worker
, NULL
);
25 static DECLARE_WORK(pmac_backlight_set_legacy_work
, pmac_backlight_set_legacy_worker
, NULL
);
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.
31 static int pmac_backlight_key_queued
;
32 static int pmac_backlight_set_legacy_queued
;
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.
38 static atomic_t kernel_backlight_disabled
= ATOMIC_INIT(0);
40 /* Protect the pmac_backlight variable */
41 DEFINE_MUTEX(pmac_backlight_mutex
);
43 /* Main backlight storage
45 * Backlight drivers in this variable are required to have the "props"
46 * attribute set and to have an update_status function.
48 * We can only store one backlight here, but since Apple laptops have only one
49 * internal display, it doesn't matter. Other backlight drivers can be used
53 * pmac_backlight_mutex (global, main backlight)
54 * pmac_backlight->sem (backlight class)
56 struct backlight_device
*pmac_backlight
;
58 int pmac_has_backlight_type(const char *type
)
60 struct device_node
* bk_node
= find_devices("backlight");
63 char *prop
= get_property(bk_node
, "backlight-control", NULL
);
64 if (prop
&& strncmp(prop
, type
, strlen(type
)) == 0)
71 int pmac_backlight_curve_lookup(struct fb_info
*info
, int value
)
73 int level
= (FB_BACKLIGHT_LEVELS
- 1);
75 if (info
&& info
->bl_dev
) {
78 /* Look for biggest value */
79 for (i
= 0; i
< FB_BACKLIGHT_LEVELS
; i
++)
80 max
= max((int)info
->bl_curve
[i
], max
);
82 /* Look for nearest value */
83 for (i
= 0; i
< FB_BACKLIGHT_LEVELS
; i
++) {
84 int diff
= abs(info
->bl_curve
[i
] - value
);
96 static void pmac_backlight_key_worker(void *data
)
98 if (atomic_read(&kernel_backlight_disabled
))
101 mutex_lock(&pmac_backlight_mutex
);
102 if (pmac_backlight
) {
103 struct backlight_properties
*props
;
106 down(&pmac_backlight
->sem
);
107 props
= pmac_backlight
->props
;
109 brightness
= props
->brightness
+
110 ((pmac_backlight_key_queued
?-1:1) *
111 (props
->max_brightness
/ 15));
115 else if (brightness
> props
->max_brightness
)
116 brightness
= props
->max_brightness
;
118 props
->brightness
= brightness
;
119 props
->update_status(pmac_backlight
);
121 up(&pmac_backlight
->sem
);
123 mutex_unlock(&pmac_backlight_mutex
);
126 /* This function is called in interrupt context */
127 void pmac_backlight_key(int direction
)
129 if (atomic_read(&kernel_backlight_disabled
))
132 /* we can receive multiple interrupts here, but the scheduled work
133 * will run only once, with the last value
135 pmac_backlight_key_queued
= direction
;
136 schedule_work(&pmac_backlight_key_work
);
139 static int __pmac_backlight_set_legacy_brightness(int brightness
)
143 mutex_lock(&pmac_backlight_mutex
);
144 if (pmac_backlight
) {
145 struct backlight_properties
*props
;
147 down(&pmac_backlight
->sem
);
148 props
= pmac_backlight
->props
;
149 props
->brightness
= brightness
*
150 (props
->max_brightness
+ 1) /
151 (OLD_BACKLIGHT_MAX
+ 1);
153 if (props
->brightness
> props
->max_brightness
)
154 props
->brightness
= props
->max_brightness
;
155 else if (props
->brightness
< 0)
156 props
->brightness
= 0;
158 props
->update_status(pmac_backlight
);
159 up(&pmac_backlight
->sem
);
163 mutex_unlock(&pmac_backlight_mutex
);
168 static void pmac_backlight_set_legacy_worker(void *data
)
170 if (atomic_read(&kernel_backlight_disabled
))
173 __pmac_backlight_set_legacy_brightness(pmac_backlight_set_legacy_queued
);
176 /* This function is called in interrupt context */
177 void pmac_backlight_set_legacy_brightness_pmu(int brightness
) {
178 if (atomic_read(&kernel_backlight_disabled
))
181 pmac_backlight_set_legacy_queued
= brightness
;
182 schedule_work(&pmac_backlight_set_legacy_work
);
185 int pmac_backlight_set_legacy_brightness(int brightness
)
187 return __pmac_backlight_set_legacy_brightness(brightness
);
190 int pmac_backlight_get_legacy_brightness()
194 mutex_lock(&pmac_backlight_mutex
);
195 if (pmac_backlight
) {
196 struct backlight_properties
*props
;
198 down(&pmac_backlight
->sem
);
199 props
= pmac_backlight
->props
;
201 result
= props
->brightness
*
202 (OLD_BACKLIGHT_MAX
+ 1) /
203 (props
->max_brightness
+ 1);
205 up(&pmac_backlight
->sem
);
207 mutex_unlock(&pmac_backlight_mutex
);
212 void pmac_backlight_disable()
214 atomic_inc(&kernel_backlight_disabled
);
217 void pmac_backlight_enable()
219 atomic_dec(&kernel_backlight_disabled
);
222 EXPORT_SYMBOL_GPL(pmac_backlight
);
223 EXPORT_SYMBOL_GPL(pmac_backlight_mutex
);
224 EXPORT_SYMBOL_GPL(pmac_has_backlight_type
);