Pull sim-fixes into release branch
[linux-2.6] / drivers / video / backlight / lcd.c
1 /*
2  * LCD Lowlevel Control Abstraction
3  *
4  * Copyright (C) 2003,2004 Hewlett-Packard Company
5  *
6  */
7
8 #include <linux/version.h>
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/device.h>
12 #include <linux/lcd.h>
13 #include <linux/notifier.h>
14 #include <linux/ctype.h>
15 #include <linux/err.h>
16 #include <linux/fb.h>
17 #include <asm/bug.h>
18
19 static ssize_t lcd_show_power(struct class_device *cdev, char *buf)
20 {
21         int rc;
22         struct lcd_device *ld = to_lcd_device(cdev);
23
24         down(&ld->sem);
25         if (likely(ld->props && ld->props->get_power))
26                 rc = sprintf(buf, "%d\n", ld->props->get_power(ld));
27         else
28                 rc = -ENXIO;
29         up(&ld->sem);
30
31         return rc;
32 }
33
34 static ssize_t lcd_store_power(struct class_device *cdev, const char *buf, size_t count)
35 {
36         int rc, power;
37         char *endp;
38         struct lcd_device *ld = to_lcd_device(cdev);
39
40         power = simple_strtoul(buf, &endp, 0);
41         if (*endp && !isspace(*endp))
42                 return -EINVAL;
43
44         down(&ld->sem);
45         if (likely(ld->props && ld->props->set_power)) {
46                 pr_debug("lcd: set power to %d\n", power);
47                 ld->props->set_power(ld, power);
48                 rc = count;
49         } else
50                 rc = -ENXIO;
51         up(&ld->sem);
52
53         return rc;
54 }
55
56 static ssize_t lcd_show_contrast(struct class_device *cdev, char *buf)
57 {
58         int rc;
59         struct lcd_device *ld = to_lcd_device(cdev);
60
61         down(&ld->sem);
62         if (likely(ld->props && ld->props->get_contrast))
63                 rc = sprintf(buf, "%d\n", ld->props->get_contrast(ld));
64         else
65                 rc = -ENXIO;
66         up(&ld->sem);
67
68         return rc;
69 }
70
71 static ssize_t lcd_store_contrast(struct class_device *cdev, const char *buf, size_t count)
72 {
73         int rc, contrast;
74         char *endp;
75         struct lcd_device *ld = to_lcd_device(cdev);
76
77         contrast = simple_strtoul(buf, &endp, 0);
78         if (*endp && !isspace(*endp))
79                 return -EINVAL;
80
81         down(&ld->sem);
82         if (likely(ld->props && ld->props->set_contrast)) {
83                 pr_debug("lcd: set contrast to %d\n", contrast);
84                 ld->props->set_contrast(ld, contrast);
85                 rc = count;
86         } else
87                 rc = -ENXIO;
88         up(&ld->sem);
89
90         return rc;
91 }
92
93 static ssize_t lcd_show_max_contrast(struct class_device *cdev, char *buf)
94 {
95         int rc;
96         struct lcd_device *ld = to_lcd_device(cdev);
97
98         down(&ld->sem);
99         if (likely(ld->props))
100                 rc = sprintf(buf, "%d\n", ld->props->max_contrast);
101         else
102                 rc = -ENXIO;
103         up(&ld->sem);
104
105         return rc;
106 }
107
108 static void lcd_class_release(struct class_device *dev)
109 {
110         struct lcd_device *ld = to_lcd_device(dev);
111         kfree(ld);
112 }
113
114 static struct class lcd_class = {
115         .name = "lcd",
116         .release = lcd_class_release,
117 };
118
119 #define DECLARE_ATTR(_name,_mode,_show,_store)                  \
120 {                                                               \
121         .attr   = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE },  \
122         .show   = _show,                                        \
123         .store  = _store,                                       \
124 }
125
126 static struct class_device_attribute lcd_class_device_attributes[] = {
127         DECLARE_ATTR(power, 0644, lcd_show_power, lcd_store_power),
128         DECLARE_ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast),
129         DECLARE_ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL),
130 };
131
132 /* This callback gets called when something important happens inside a
133  * framebuffer driver. We're looking if that important event is blanking,
134  * and if it is, we're switching lcd power as well ...
135  */
136 static int fb_notifier_callback(struct notifier_block *self,
137                                  unsigned long event, void *data)
138 {
139         struct lcd_device *ld;
140         struct fb_event *evdata =(struct fb_event *)data;
141
142         /* If we aren't interested in this event, skip it immediately ... */
143         if (event != FB_EVENT_BLANK)
144                 return 0;
145
146         ld = container_of(self, struct lcd_device, fb_notif);
147         down(&ld->sem);
148         if (ld->props)
149                 if (!ld->props->check_fb || ld->props->check_fb(evdata->info))
150                         ld->props->set_power(ld, *(int *)evdata->data);
151         up(&ld->sem);
152         return 0;
153 }
154
155 /**
156  * lcd_device_register - register a new object of lcd_device class.
157  * @name: the name of the new object(must be the same as the name of the
158  *   respective framebuffer device).
159  * @devdata: an optional pointer to be stored in the class_device. The
160  *   methods may retrieve it by using class_get_devdata(ld->class_dev).
161  * @lp: the lcd properties structure.
162  *
163  * Creates and registers a new lcd class_device. Returns either an ERR_PTR()
164  * or a pointer to the newly allocated device.
165  */
166 struct lcd_device *lcd_device_register(const char *name, void *devdata,
167                                        struct lcd_properties *lp)
168 {
169         int i, rc;
170         struct lcd_device *new_ld;
171
172         pr_debug("lcd_device_register: name=%s\n", name);
173
174         new_ld = kmalloc(sizeof(struct lcd_device), GFP_KERNEL);
175         if (unlikely(!new_ld))
176                 return ERR_PTR(ENOMEM);
177
178         init_MUTEX(&new_ld->sem);
179         new_ld->props = lp;
180         memset(&new_ld->class_dev, 0, sizeof(new_ld->class_dev));
181         new_ld->class_dev.class = &lcd_class;
182         strlcpy(new_ld->class_dev.class_id, name, KOBJ_NAME_LEN);
183         class_set_devdata(&new_ld->class_dev, devdata);
184
185         rc = class_device_register(&new_ld->class_dev);
186         if (unlikely(rc)) {
187 error:          kfree(new_ld);
188                 return ERR_PTR(rc);
189         }
190
191         memset(&new_ld->fb_notif, 0, sizeof(new_ld->fb_notif));
192         new_ld->fb_notif.notifier_call = fb_notifier_callback;
193
194         rc = fb_register_client(&new_ld->fb_notif);
195         if (unlikely(rc))
196                 goto error;
197
198         for (i = 0; i < ARRAY_SIZE(lcd_class_device_attributes); i++) {
199                 rc = class_device_create_file(&new_ld->class_dev,
200                                               &lcd_class_device_attributes[i]);
201                 if (unlikely(rc)) {
202                         while (--i >= 0)
203                                 class_device_remove_file(&new_ld->class_dev,
204                                                          &lcd_class_device_attributes[i]);
205                         class_device_unregister(&new_ld->class_dev);
206                         /* No need to kfree(new_ld) since release() method was called */
207                         return ERR_PTR(rc);
208                 }
209         }
210
211         return new_ld;
212 }
213 EXPORT_SYMBOL(lcd_device_register);
214
215 /**
216  * lcd_device_unregister - unregisters a object of lcd_device class.
217  * @ld: the lcd device object to be unregistered and freed.
218  *
219  * Unregisters a previously registered via lcd_device_register object.
220  */
221 void lcd_device_unregister(struct lcd_device *ld)
222 {
223         int i;
224
225         if (!ld)
226                 return;
227
228         pr_debug("lcd_device_unregister: name=%s\n", ld->class_dev.class_id);
229
230         for (i = 0; i < ARRAY_SIZE(lcd_class_device_attributes); i++)
231                 class_device_remove_file(&ld->class_dev,
232                                          &lcd_class_device_attributes[i]);
233
234         down(&ld->sem);
235         ld->props = NULL;
236         up(&ld->sem);
237
238         fb_unregister_client(&ld->fb_notif);
239
240         class_device_unregister(&ld->class_dev);
241 }
242 EXPORT_SYMBOL(lcd_device_unregister);
243
244 static void __exit lcd_class_exit(void)
245 {
246         class_unregister(&lcd_class);
247 }
248
249 static int __init lcd_class_init(void)
250 {
251         return class_register(&lcd_class);
252 }
253
254 /*
255  * if this is compiled into the kernel, we need to ensure that the
256  * class is registered before users of the class try to register lcd's
257  */
258 postcore_initcall(lcd_class_init);
259 module_exit(lcd_class_exit);
260
261 MODULE_LICENSE("GPL");
262 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
263 MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");