drivers/video/backlight/lcd.c

   1 /*
   2  * LCD Lowlevel Control Abstraction
   3  *
   4  * Copyright (C) 2003,2004 Hewlett-Packard Company
   5  *
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/device.h>
  13 #include <linux/lcd.h>
  14 #include <linux/notifier.h>
  15 #include <linux/ctype.h>
  16 #include <linux/err.h>
  17 #include <linux/fb.h>
  18 #include <linux/slab.h>
  19
  20 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
  21                            defined(CONFIG_LCD_CLASS_DEVICE_MODULE))
  22 /* This callback gets called when something important happens inside a
  23  * framebuffer driver. We're looking if that important event is blanking,
  24  * and if it is, we're switching lcd power as well ...
  25  */
  26 static int fb_notifier_callback(struct notifier_block *self,
  27                                  unsigned long event, void *data)
  28 {
  29         struct lcd_device *ld;
  30         struct fb_event *evdata = data;
  31
  32         /* If we aren't interested in this event, skip it immediately ... */
  33         switch (event) {
  34         case FB_EVENT_BLANK:
  35         case FB_EVENT_MODE_CHANGE:
  36         case FB_EVENT_MODE_CHANGE_ALL:
  37         case FB_EARLY_EVENT_BLANK:
  38         case FB_R_EARLY_EVENT_BLANK:
  39                 break;
  40         default:
  41                 return 0;
  42         }
  43
  44         ld = container_of(self, struct lcd_device, fb_notif);
  45         if (!ld->ops)
  46                 return 0;
  47
  48         mutex_lock(&ld->ops_lock);
  49         if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) {
  50                 if (event == FB_EVENT_BLANK) {
  51                         if (ld->ops->set_power)
  52                                 ld->ops->set_power(ld, *(int *)evdata->data);
  53                 } else if (event == FB_EARLY_EVENT_BLANK) {
  54                         if (ld->ops->early_set_power)
  55                                 ld->ops->early_set_power(ld,
  56                                                 *(int *)evdata->data);
  57                 } else if (event == FB_R_EARLY_EVENT_BLANK) {
  58                         if (ld->ops->r_early_set_power)
  59                                 ld->ops->r_early_set_power(ld,
  60                                                 *(int *)evdata->data);
  61                 } else {
  62                         if (ld->ops->set_mode)
  63                                 ld->ops->set_mode(ld, evdata->data);
  64                 }
  65         }
  66         mutex_unlock(&ld->ops_lock);
  67         return 0;
  68 }
  69
  70 static int lcd_register_fb(struct lcd_device *ld)
  71 {
  72         memset(&ld->fb_notif, 0, sizeof(ld->fb_notif));
  73         ld->fb_notif.notifier_call = fb_notifier_callback;
  74         return fb_register_client(&ld->fb_notif);
  75 }
  76
  77 static void lcd_unregister_fb(struct lcd_device *ld)
  78 {
  79         fb_unregister_client(&ld->fb_notif);
  80 }
  81 #else
  82 static int lcd_register_fb(struct lcd_device *ld)
  83 {
  84         return 0;
  85 }
  86
  87 static inline void lcd_unregister_fb(struct lcd_device *ld)
  88 {
  89 }
  90 #endif /* CONFIG_FB */
  91
  92 static ssize_t lcd_power_show(struct device *dev, struct device_attribute *attr,
  93                 char *buf)
  94 {
  95         int rc;
  96         struct lcd_device *ld = to_lcd_device(dev);
  97
  98         mutex_lock(&ld->ops_lock);
  99         if (ld->ops && ld->ops->get_power)
 100                 rc = sprintf(buf, "%d\n", ld->ops->get_power(ld));
 101         else
 102                 rc = -ENXIO;
 103         mutex_unlock(&ld->ops_lock);
 104
 105         return rc;
 106 }
 107
 108 static ssize_t lcd_power_store(struct device *dev,
 109                 struct device_attribute *attr, const char *buf, size_t count)
 110 {
 111         int rc;
 112         struct lcd_device *ld = to_lcd_device(dev);
 113         unsigned long power;
 114
 115         rc = kstrtoul(buf, 0, &power);
 116         if (rc)
 117                 return rc;
 118
 119         rc = -ENXIO;
 120
 121         mutex_lock(&ld->ops_lock);
 122         if (ld->ops && ld->ops->set_power) {
 123                 pr_debug("set power to %lu\n", power);
 124                 ld->ops->set_power(ld, power);
 125                 rc = count;
 126         }
 127         mutex_unlock(&ld->ops_lock);
 128
 129         return rc;
 130 }
 131 static DEVICE_ATTR_RW(lcd_power);
 132
 133 static ssize_t contrast_show(struct device *dev,
 134                 struct device_attribute *attr, char *buf)
 135 {
 136         int rc = -ENXIO;
 137         struct lcd_device *ld = to_lcd_device(dev);
 138
 139         mutex_lock(&ld->ops_lock);
 140         if (ld->ops && ld->ops->get_contrast)
 141                 rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld));
 142         mutex_unlock(&ld->ops_lock);
 143
 144         return rc;
 145 }
 146
 147 static ssize_t contrast_store(struct device *dev,
 148                 struct device_attribute *attr, const char *buf, size_t count)
 149 {
 150         int rc;
 151         struct lcd_device *ld = to_lcd_device(dev);
 152         unsigned long contrast;
 153
 154         rc = kstrtoul(buf, 0, &contrast);
 155         if (rc)
 156                 return rc;
 157
 158         rc = -ENXIO;
 159
 160         mutex_lock(&ld->ops_lock);
 161         if (ld->ops && ld->ops->set_contrast) {
 162                 pr_debug("set contrast to %lu\n", contrast);
 163                 ld->ops->set_contrast(ld, contrast);
 164                 rc = count;
 165         }
 166         mutex_unlock(&ld->ops_lock);
 167
 168         return rc;
 169 }
 170 static DEVICE_ATTR_RW(contrast);
 171
 172 static ssize_t max_contrast_show(struct device *dev,
 173                 struct device_attribute *attr, char *buf)
 174 {
 175         struct lcd_device *ld = to_lcd_device(dev);
 176
 177         return sprintf(buf, "%d\n", ld->props.max_contrast);
 178 }
 179 static DEVICE_ATTR_RO(max_contrast);
 180
 181 static struct class *lcd_class;
 182
 183 static void lcd_device_release(struct device *dev)
 184 {
 185         struct lcd_device *ld = to_lcd_device(dev);
 186         kfree(ld);
 187 }
 188
 189 static struct attribute *lcd_device_attrs[] = {
 190         &dev_attr_lcd_power.attr,
 191         &dev_attr_contrast.attr,
 192         &dev_attr_max_contrast.attr,
 193         NULL,
 194 };
 195 ATTRIBUTE_GROUPS(lcd_device);
 196
 197 /**
 198  * lcd_device_register - register a new object of lcd_device class.
 199  * @name: the name of the new object(must be the same as the name of the
 200  *   respective framebuffer device).
 201  * @devdata: an optional pointer to be stored in the device. The
 202  *   methods may retrieve it by using lcd_get_data(ld).
 203  * @ops: the lcd operations structure.
 204  *
 205  * Creates and registers a new lcd device. Returns either an ERR_PTR()
 206  * or a pointer to the newly allocated device.
 207  */
 208 struct lcd_device *lcd_device_register(const char *name, struct device *parent,
 209                 void *devdata, struct lcd_ops *ops)
 210 {
 211         struct lcd_device *new_ld;
 212         int rc;
 213
 214         pr_debug("lcd_device_register: name=%s\n", name);
 215
 216         new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL);
 217         if (!new_ld)
 218                 return ERR_PTR(-ENOMEM);
 219
 220         mutex_init(&new_ld->ops_lock);
 221         mutex_init(&new_ld->update_lock);
 222
 223         new_ld->dev.class = lcd_class;
 224         new_ld->dev.parent = parent;
 225         new_ld->dev.release = lcd_device_release;
 226         dev_set_name(&new_ld->dev, "%s", name);
 227         dev_set_drvdata(&new_ld->dev, devdata);
 228
 229         rc = device_register(&new_ld->dev);
 230         if (rc) {
 231                 kfree(new_ld);
 232                 return ERR_PTR(rc);
 233         }
 234
 235         rc = lcd_register_fb(new_ld);
 236         if (rc) {
 237                 device_unregister(&new_ld->dev);
 238                 return ERR_PTR(rc);
 239         }
 240
 241         new_ld->ops = ops;
 242
 243         return new_ld;
 244 }
 245 EXPORT_SYMBOL(lcd_device_register);
 246
 247 /**
 248  * lcd_device_unregister - unregisters a object of lcd_device class.
 249  * @ld: the lcd device object to be unregistered and freed.
 250  *
 251  * Unregisters a previously registered via lcd_device_register object.
 252  */
 253 void lcd_device_unregister(struct lcd_device *ld)
 254 {
 255         if (!ld)
 256                 return;
 257
 258         mutex_lock(&ld->ops_lock);
 259         ld->ops = NULL;
 260         mutex_unlock(&ld->ops_lock);
 261         lcd_unregister_fb(ld);
 262
 263         device_unregister(&ld->dev);
 264 }
 265 EXPORT_SYMBOL(lcd_device_unregister);
 266
 267 static void devm_lcd_device_release(struct device *dev, void *res)
 268 {
 269         struct lcd_device *lcd = *(struct lcd_device **)res;
 270
 271         lcd_device_unregister(lcd);
 272 }
 273
 274 static int devm_lcd_device_match(struct device *dev, void *res, void *data)
 275 {
 276         struct lcd_device **r = res;
 277
 278         return *r == data;
 279 }
 280
 281 /**
 282  * devm_lcd_device_register - resource managed lcd_device_register()
 283  * @dev: the device to register
 284  * @name: the name of the device
 285  * @parent: a pointer to the parent device
 286  * @devdata: an optional pointer to be stored for private driver use
 287  * @ops: the lcd operations structure
 288  *
 289  * @return a struct lcd on success, or an ERR_PTR on error
 290  *
 291  * Managed lcd_device_register(). The lcd_device returned from this function
 292  * are automatically freed on driver detach. See lcd_device_register()
 293  * for more information.
 294  */
 295 struct lcd_device *devm_lcd_device_register(struct device *dev,
 296                 const char *name, struct device *parent,
 297                 void *devdata, struct lcd_ops *ops)
 298 {
 299         struct lcd_device **ptr, *lcd;
 300
 301         ptr = devres_alloc(devm_lcd_device_release, sizeof(*ptr), GFP_KERNEL);
 302         if (!ptr)
 303                 return ERR_PTR(-ENOMEM);
 304
 305         lcd = lcd_device_register(name, parent, devdata, ops);
 306         if (!IS_ERR(lcd)) {
 307                 *ptr = lcd;
 308                 devres_add(dev, ptr);
 309         } else {
 310                 devres_free(ptr);
 311         }
 312
 313         return lcd;
 314 }
 315 EXPORT_SYMBOL(devm_lcd_device_register);
 316
 317 /**
 318  * devm_lcd_device_unregister - resource managed lcd_device_unregister()
 319  * @dev: the device to unregister
 320  * @ld: the lcd device to unregister
 321  *
 322  * Deallocated a lcd allocated with devm_lcd_device_register(). Normally
 323  * this function will not need to be called and the resource management
 324  * code will ensure that the resource is freed.
 325  */
 326 void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld)
 327 {
 328         int rc;
 329
 330         rc = devres_release(dev, devm_lcd_device_release,
 331                                 devm_lcd_device_match, ld);
 332         WARN_ON(rc);
 333 }
 334 EXPORT_SYMBOL(devm_lcd_device_unregister);
 335
 336
 337 static void __exit lcd_class_exit(void)
 338 {
 339         class_destroy(lcd_class);
 340 }
 341
 342 static int __init lcd_class_init(void)
 343 {
 344         lcd_class = class_create(THIS_MODULE, "lcd");
 345         if (IS_ERR(lcd_class)) {
 346                 pr_warn("Unable to create backlight class; errno = %ld\n",
 347                         PTR_ERR(lcd_class));
 348                 return PTR_ERR(lcd_class);
 349         }
 350
 351         lcd_class->dev_groups = lcd_device_groups;
 352         return 0;
 353 }
 354
 355 /*
 356  * if this is compiled into the kernel, we need to ensure that the
 357  * class is registered before users of the class try to register lcd's
 358  */
 359 postcore_initcall(lcd_class_init);
 360 module_exit(lcd_class_exit);
 361
 362 MODULE_LICENSE("GPL");
 363 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
 364 MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");