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 #ifdef CONFIG_PMAC_BACKLIGHT
  18 #include <asm/backlight.h>
  19 #endif
  20
  21 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
  22                            defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE))
  23 /* This callback gets called when something important happens inside a
  24  * framebuffer driver. We're looking if that important event is blanking,
  25  * and if it is, we're switching backlight power as well ...
  26  */
  27 static int fb_notifier_callback(struct notifier_block *self,
  28                                 unsigned long event, void *data)
  29 {
  30         struct backlight_device *bd;
  31         struct fb_event *evdata = data;
  32
  33         /* If we aren't interested in this event, skip it immediately ... */
  34         if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
  35                 return 0;
  36
  37         bd = container_of(self, struct backlight_device, fb_notif);
  38         mutex_lock(&bd->ops_lock);
  39         if (bd->ops)
  40                 if (!bd->ops->check_fb ||
  41                     bd->ops->check_fb(evdata->info)) {
  42                         bd->props.fb_blank = *(int *)evdata->data;
  43                         if (bd->props.fb_blank == FB_BLANK_UNBLANK)
  44                                 bd->props.state &= ~BL_CORE_FBBLANK;
  45                         else
  46                                 bd->props.state |= BL_CORE_FBBLANK;
  47                         backlight_update_status(bd);
  48                 }
  49         mutex_unlock(&bd->ops_lock);
  50         return 0;
  51 }
  52
  53 static int backlight_register_fb(struct backlight_device *bd)
  54 {
  55         memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));
  56         bd->fb_notif.notifier_call = fb_notifier_callback;
  57
  58         return fb_register_client(&bd->fb_notif);
  59 }
  60
  61 static void backlight_unregister_fb(struct backlight_device *bd)
  62 {
  63         fb_unregister_client(&bd->fb_notif);
  64 }
  65 #else
  66 static inline int backlight_register_fb(struct backlight_device *bd)
  67 {
  68         return 0;
  69 }
  70
  71 static inline void backlight_unregister_fb(struct backlight_device *bd)
  72 {
  73 }
  74 #endif /* CONFIG_FB */
  75
  76 static ssize_t backlight_show_power(struct device *dev,
  77                 struct device_attribute *attr,char *buf)
  78 {
  79         struct backlight_device *bd = to_backlight_device(dev);
  80
  81         return sprintf(buf, "%d\n", bd->props.power);
  82 }
  83
  84 static ssize_t backlight_store_power(struct device *dev,
  85                 struct device_attribute *attr, const char *buf, size_t count)
  86 {
  87         int rc;
  88         struct backlight_device *bd = to_backlight_device(dev);
  89         unsigned long power;
  90
  91         rc = strict_strtoul(buf, 0, &power);
  92         if (rc)
  93                 return rc;
  94
  95         rc = -ENXIO;
  96         mutex_lock(&bd->ops_lock);
  97         if (bd->ops) {
  98                 pr_debug("backlight: set power to %lu\n", power);
  99                 if (bd->props.power != power) {
 100                         bd->props.power = power;
 101                         backlight_update_status(bd);
 102                 }
 103                 rc = count;
 104         }
 105         mutex_unlock(&bd->ops_lock);
 106
 107         return rc;
 108 }
 109
 110 static ssize_t backlight_show_brightness(struct device *dev,
 111                 struct device_attribute *attr, char *buf)
 112 {
 113         struct backlight_device *bd = to_backlight_device(dev);
 114
 115         return sprintf(buf, "%d\n", bd->props.brightness);
 116 }
 117
 118 static ssize_t backlight_store_brightness(struct device *dev,
 119                 struct device_attribute *attr, const char *buf, size_t count)
 120 {
 121         int rc;
 122         struct backlight_device *bd = to_backlight_device(dev);
 123         unsigned long brightness;
 124
 125         rc = strict_strtoul(buf, 0, &brightness);
 126         if (rc)
 127                 return rc;
 128
 129         rc = -ENXIO;
 130
 131         mutex_lock(&bd->ops_lock);
 132         if (bd->ops) {
 133                 if (brightness > bd->props.max_brightness)
 134                         rc = -EINVAL;
 135                 else {
 136                         pr_debug("backlight: set brightness to %lu\n",
 137                                  brightness);
 138                         bd->props.brightness = brightness;
 139                         backlight_update_status(bd);
 140                         rc = count;
 141                 }
 142         }
 143         mutex_unlock(&bd->ops_lock);
 144
 145         return rc;
 146 }
 147
 148 static ssize_t backlight_show_max_brightness(struct device *dev,
 149                 struct device_attribute *attr, char *buf)
 150 {
 151         struct backlight_device *bd = to_backlight_device(dev);
 152
 153         return sprintf(buf, "%d\n", bd->props.max_brightness);
 154 }
 155
 156 static ssize_t backlight_show_actual_brightness(struct device *dev,
 157                 struct device_attribute *attr, char *buf)
 158 {
 159         int rc = -ENXIO;
 160         struct backlight_device *bd = to_backlight_device(dev);
 161
 162         mutex_lock(&bd->ops_lock);
 163         if (bd->ops && bd->ops->get_brightness)
 164                 rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));
 165         mutex_unlock(&bd->ops_lock);
 166
 167         return rc;
 168 }
 169
 170 static struct class *backlight_class;
 171
 172 static int backlight_suspend(struct device *dev, pm_message_t state)
 173 {
 174         struct backlight_device *bd = to_backlight_device(dev);
 175
 176         if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
 177                 mutex_lock(&bd->ops_lock);
 178                 bd->props.state |= BL_CORE_SUSPENDED;
 179                 backlight_update_status(bd);
 180                 mutex_unlock(&bd->ops_lock);
 181         }
 182
 183         return 0;
 184 }
 185
 186 static int backlight_resume(struct device *dev)
 187 {
 188         struct backlight_device *bd = to_backlight_device(dev);
 189
 190         if (bd->ops->options & BL_CORE_SUSPENDRESUME) {
 191                 mutex_lock(&bd->ops_lock);
 192                 bd->props.state &= ~BL_CORE_SUSPENDED;
 193                 backlight_update_status(bd);
 194                 mutex_unlock(&bd->ops_lock);
 195         }
 196
 197         return 0;
 198 }
 199
 200 static void bl_device_release(struct device *dev)
 201 {
 202         struct backlight_device *bd = to_backlight_device(dev);
 203         kfree(bd);
 204 }
 205
 206 static struct device_attribute bl_device_attributes[] = {
 207         __ATTR(bl_power, 0644, backlight_show_power, backlight_store_power),
 208         __ATTR(brightness, 0644, backlight_show_brightness,
 209                      backlight_store_brightness),
 210         __ATTR(actual_brightness, 0444, backlight_show_actual_brightness,
 211                      NULL),
 212         __ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),
 213         __ATTR_NULL,
 214 };
 215
 216 /**
 217  * backlight_device_register - create and register a new object of
 218  *   backlight_device class.
 219  * @name: the name of the new object(must be the same as the name of the
 220  *   respective framebuffer device).
 221  * @parent: a pointer to the parent device
 222  * @devdata: an optional pointer to be stored for private driver use. The
 223  *   methods may retrieve it by using bl_get_data(bd).
 224  * @ops: the backlight operations structure.
 225  *
 226  * Creates and registers new backlight device. Returns either an
 227  * ERR_PTR() or a pointer to the newly allocated device.
 228  */
 229 struct backlight_device *backlight_device_register(const char *name,
 230                 struct device *parent, void *devdata, struct backlight_ops *ops)
 231 {
 232         struct backlight_device *new_bd;
 233         int rc;
 234
 235         pr_debug("backlight_device_register: name=%s\n", name);
 236
 237         new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);
 238         if (!new_bd)
 239                 return ERR_PTR(-ENOMEM);
 240
 241         mutex_init(&new_bd->update_lock);
 242         mutex_init(&new_bd->ops_lock);
 243
 244         new_bd->dev.class = backlight_class;
 245         new_bd->dev.parent = parent;
 246         new_bd->dev.release = bl_device_release;
 247         dev_set_name(&new_bd->dev, name);
 248         dev_set_drvdata(&new_bd->dev, devdata);
 249
 250         rc = device_register(&new_bd->dev);
 251         if (rc) {
 252                 kfree(new_bd);
 253                 return ERR_PTR(rc);
 254         }
 255
 256         rc = backlight_register_fb(new_bd);
 257         if (rc) {
 258                 device_unregister(&new_bd->dev);
 259                 return ERR_PTR(rc);
 260         }
 261
 262         new_bd->ops = ops;
 263
 264 #ifdef CONFIG_PMAC_BACKLIGHT
 265         mutex_lock(&pmac_backlight_mutex);
 266         if (!pmac_backlight)
 267                 pmac_backlight = new_bd;
 268         mutex_unlock(&pmac_backlight_mutex);
 269 #endif
 270
 271         return new_bd;
 272 }
 273 EXPORT_SYMBOL(backlight_device_register);
 274
 275 /**
 276  * backlight_device_unregister - unregisters a backlight device object.
 277  * @bd: the backlight device object to be unregistered and freed.
 278  *
 279  * Unregisters a previously registered via backlight_device_register object.
 280  */
 281 void backlight_device_unregister(struct backlight_device *bd)
 282 {
 283         if (!bd)
 284                 return;
 285
 286 #ifdef CONFIG_PMAC_BACKLIGHT
 287         mutex_lock(&pmac_backlight_mutex);
 288         if (pmac_backlight == bd)
 289                 pmac_backlight = NULL;
 290         mutex_unlock(&pmac_backlight_mutex);
 291 #endif
 292         mutex_lock(&bd->ops_lock);
 293         bd->ops = NULL;
 294         mutex_unlock(&bd->ops_lock);
 295
 296         backlight_unregister_fb(bd);
 297         device_unregister(&bd->dev);
 298 }
 299 EXPORT_SYMBOL(backlight_device_unregister);
 300
 301 static void __exit backlight_class_exit(void)
 302 {
 303         class_destroy(backlight_class);
 304 }
 305
 306 static int __init backlight_class_init(void)
 307 {
 308         backlight_class = class_create(THIS_MODULE, "backlight");
 309         if (IS_ERR(backlight_class)) {
 310                 printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",
 311                                 PTR_ERR(backlight_class));
 312                 return PTR_ERR(backlight_class);
 313         }
 314
 315         backlight_class->dev_attrs = bl_device_attributes;
 316         backlight_class->suspend = backlight_suspend;
 317         backlight_class->resume = backlight_resume;
 318         return 0;
 319 }
 320
 321 /*
 322  * if this is compiled into the kernel, we need to ensure that the
 323  * class is registered before users of the class try to register lcd's
 324  */
 325 postcore_initcall(backlight_class_init);
 326 module_exit(backlight_class_exit);
 327
 328 MODULE_LICENSE("GPL");
 329 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
 330 MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");