SAFE public projects git trees. - safe/jmp/linux-2.6/blob - drivers/video/backlight/backlight.c

   1 /*
   2  * Backlight Lowlevel Control Abstraction
   3  *
   4  * Copyright (C) 2003,2004 Hewlett-Packard Company
   5  *
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/device.h>
  11 #include <linux/backlight.h>
  12 #include <linux/notifier.h>
  13 #include <linux/ctype.h>
  14 #include <linux/err.h>
  15 #include <linux/fb.h>
  16
  17
  18 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
  19                            defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
  20 /* This callback gets called when something important happens inside a
  21  * framebuffer driver. We're looking if that important event is blanking,
  22  * and if it is, we're switching backlight power as well ...
  23  */
  24 static int fb_notifier_callback(struct notifier_block *self,
  25                                 unsigned long event, void *data)
  26 {
  27         struct backlight_device *bd;
  28         struct fb_event *evdata = data;
  29
  30         /* If we aren't interested in this event, skip it immediately ... */
  31         if (event != FB_EVENT_BLANK)
  32                 return 0;
  33
  34         bd = container_of(self, struct backlight_device, fb_notif);
  35         down(&bd->sem);
  36         if (bd->props)
  37                 if (!bd->props->check_fb ||
  38                     bd->props->check_fb(evdata->info)) {
  39                         bd->props->fb_blank = *(int *)evdata->data;
  40                         backlight_update_status(bd);
  41                 }
  42         up(&bd->sem);
  43         return 0;
  44 }
  45
  46 static int backlight_register_fb(struct backlight_device *bd)
  47 {
  48         memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
  49         bd->fb_notif.notifier_call = fb_notifier_callback;
  50
  51         return fb_register_client(&bd->fb_notif);
  52 }
  53
  54 static void backlight_unregister_fb(struct backlight_device *bd)
  55 {
  56         fb_unregister_client(&bd->fb_notif);
  57 }
  58 #else
  59 static inline int backlight_register_fb(struct backlight_device *bd)
  60 {
  61         return 0;
  62 }
  63
  64 static inline void backlight_unregister_fb(struct backlight_device *bd)
  65 {
  66 }
  67 #endif /* CONFIG_FB */
  68
  69 static ssize_t backlight_show_power(struct class_device *cdev, char *buf)
  70 {
  71         int rc = -ENXIO;
  72         struct backlight_device *bd = to_backlight_device(cdev);
  73
  74         down(&bd->sem);
  75         if (bd->props)
  76                 rc = sprintf(buf, "%d\n", bd->props->power);
  77         up(&bd->sem);
  78
  79         return rc;
  80 }
  81
  82 static ssize_t backlight_store_power(struct class_device *cdev, const char *buf, size_t count)
  83 {
  84         int rc = -ENXIO;
  85         char *endp;
  86         struct backlight_device *bd = to_backlight_device(cdev);
  87         int power = simple_strtoul(buf, &endp, 0);
  88         size_t size = endp - buf;
  89
  90         if (*endp && isspace(*endp))
  91                 size++;
  92         if (size != count)
  93                 return -EINVAL;
  94
  95         down(&bd->sem);
  96         if (bd->props) {
  97                 pr_debug("backlight: set power to %d\n", power);
  98                 bd->props->power = power;
  99                 backlight_update_status(bd);
 100                 rc = count;
 101         }
 102         up(&bd->sem);
 103
 104         return rc;
 105 }
 106
 107 static ssize_t backlight_show_brightness(struct class_device *cdev, char *buf)
 108 {
 109         int rc = -ENXIO;
 110         struct backlight_device *bd = to_backlight_device(cdev);
 111
 112         down(&bd->sem);
 113         if (bd->props)
 114                 rc = sprintf(buf, "%d\n", bd->props->brightness);
 115         up(&bd->sem);
 116
 117         return rc;
 118 }
 119
 120 static ssize_t backlight_store_brightness(struct class_device *cdev, const char *buf, size_t count)
 121 {
 122         int rc = -ENXIO;
 123         char *endp;
 124         struct backlight_device *bd = to_backlight_device(cdev);
 125         int brightness = simple_strtoul(buf, &endp, 0);
 126         size_t size = endp - buf;
 127
 128         if (*endp && isspace(*endp))
 129                 size++;
 130         if (size != count)
 131                 return -EINVAL;
 132
 133         down(&bd->sem);
 134         if (bd->props) {
 135                 if (brightness > bd->props->max_brightness)
 136                         rc = -EINVAL;
 137                 else {
 138                         pr_debug("backlight: set brightness to %d\n",
 139                                  brightness);
 140                         bd->props->brightness = brightness;
 141                         backlight_update_status(bd);
 142                         rc = count;
 143                 }
 144         }
 145         up(&bd->sem);
 146
 147         return rc;
 148 }
 149
 150 static ssize_t backlight_show_max_brightness(struct class_device *cdev, char *buf)
 151 {
 152         int rc = -ENXIO;
 153         struct backlight_device *bd = to_backlight_device(cdev);
 154
 155         down(&bd->sem);
 156         if (bd->props)
 157                 rc = sprintf(buf, "%d\n", bd->props->max_brightness);
 158         up(&bd->sem);
 159
 160         return rc;
 161 }
 162
 163 static ssize_t backlight_show_actual_brightness(struct class_device *cdev,
 164                                                 char *buf)
 165 {
 166         int rc = -ENXIO;
 167         struct backlight_device *bd = to_backlight_device(cdev);
 168
 169         down(&bd->sem);
 170         if (bd->props && bd->props->get_brightness)
 171                 rc = sprintf(buf, "%d\n", bd->props->get_brightness(bd));
 172         up(&bd->sem);
 173
 174         return rc;
 175 }
 176
 177 static void backlight_class_release(struct class_device *dev)
 178 {
 179         struct backlight_device *bd = to_backlight_device(dev);
 180         kfree(bd);
 181 }
 182
 183 static struct class backlight_class = {
 184         .name = "backlight",
 185         .release = backlight_class_release,
 186 };
 187
 188 #define DECLARE_ATTR(_name,_mode,_show,_store)                  \
 189 {                                                               \
 190         .attr   = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE },  \
 191         .show   = _show,                                        \
 192         .store  = _store,                                       \
 193 }
 194
 195 static const struct class_device_attribute bl_class_device_attributes[] = {
 196         DECLARE_ATTR(power, 0644, backlight_show_power, backlight_store_power),
 197         DECLARE_ATTR(brightness, 0644, backlight_show_brightness,
 198                      backlight_store_brightness),
 199         DECLARE_ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
 200                      NULL),
 201         DECLARE_ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
 202 };
 203
 204 /**
 205  * backlight_device_register - create and register a new object of
 206  *   backlight_device class.
 207  * @name: the name of the new object(must be the same as the name of the
 208  *   respective framebuffer device).
 209  * @devdata: an optional pointer to be stored in the class_device. The
 210  *   methods may retrieve it by using class_get_devdata(&bd->class_dev).
 211  * @bp: the backlight properties structure.
 212  *
 213  * Creates and registers new backlight class_device. Returns either an
 214  * ERR_PTR() or a pointer to the newly allocated device.
 215  */
 216 struct backlight_device *backlight_device_register(const char *name,
 217         struct device *dev,
 218         void *devdata,
 219         struct backlight_properties *bp)
 220 {
 221         int i, rc;
 222         struct backlight_device *new_bd;
 223
 224         pr_debug("backlight_device_alloc: name=%s\n", name);
 225
 226         new_bd = kmalloc(sizeof(struct backlight_device), GFP_KERNEL);
 227         if (!new_bd)
 228                 return ERR_PTR(-ENOMEM);
 229
 230         mutex_init(&new_bd->update_lock);
 231         init_MUTEX(&new_bd->sem);
 232         new_bd->props = bp;
 233         memset(&new_bd->class_dev, 0, sizeof(new_bd->class_dev));
 234         new_bd->class_dev.class = &backlight_class;
 235         new_bd->class_dev.dev = dev;
 236         strlcpy(new_bd->class_dev.class_id, name, KOBJ_NAME_LEN);
 237         class_set_devdata(&new_bd->class_dev, devdata);
 238
 239         rc = class_device_register(&new_bd->class_dev);
 240         if (rc) {
 241                 kfree(new_bd);
 242                 return ERR_PTR(rc);
 243         }
 244
 245         rc = backlight_register_fb(new_bd);
 246         if (rc) {
 247                 class_device_unregister(&new_bd->class_dev);
 248                 return ERR_PTR(rc);
 249         }
 250
 251
 252         for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++) {
 253                 rc = class_device_create_file(&new_bd->class_dev,
 254                                               &bl_class_device_attributes[i]);
 255                 if (rc) {
 256                         while (--i >= 0)
 257                                 class_device_remove_file(&new_bd->class_dev,
 258                                                          &bl_class_device_attributes[i]);
 259                         class_device_unregister(&new_bd->class_dev);
 260                         /* No need to kfree(new_bd) since release() method was called */
 261                         return ERR_PTR(rc);
 262                 }
 263         }
 264
 265         return new_bd;
 266 }
 267 EXPORT_SYMBOL(backlight_device_register);
 268
 269 /**
 270  * backlight_device_unregister - unregisters a backlight device object.
 271  * @bd: the backlight device object to be unregistered and freed.
 272  *
 273  * Unregisters a previously registered via backlight_device_register object.
 274  */
 275 void backlight_device_unregister(struct backlight_device *bd)
 276 {
 277         int i;
 278
 279         if (!bd)
 280                 return;
 281
 282         pr_debug("backlight_device_unregister: name=%s\n", bd->class_dev.class_id);
 283
 284         for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++)
 285                 class_device_remove_file(&bd->class_dev,
 286                                          &bl_class_device_attributes[i]);
 287
 288         down(&bd->sem);
 289         bd->props = NULL;
 290         up(&bd->sem);
 291
 292         backlight_unregister_fb(bd);
 293
 294         class_device_unregister(&bd->class_dev);
 295 }
 296 EXPORT_SYMBOL(backlight_device_unregister);
 297
 298 static void __exit backlight_class_exit(void)
 299 {
 300         class_unregister(&backlight_class);
 301 }
 302
 303 static int __init backlight_class_init(void)
 304 {
 305         return class_register(&backlight_class);
 306 }
 307
 308 /*
 309  * if this is compiled into the kernel, we need to ensure that the
 310  * class is registered before users of the class try to register lcd's
 311  */
 312 postcore_initcall(backlight_class_init);
 313 module_exit(backlight_class_exit);
 314
 315 MODULE_LICENSE("GPL");
 316 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
 317 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");