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 put_device(&new_ld->dev); 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"); 365