1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * LCD Lowlevel Control Abstraction 4 * 5 * Copyright (C) 2003,2004 Hewlett-Packard Company 6 * 7 */ 8 9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 11 #include <linux/module.h> 12 #include <linux/init.h> 13 #include <linux/device.h> 14 #include <linux/lcd.h> 15 #include <linux/notifier.h> 16 #include <linux/ctype.h> 17 #include <linux/err.h> 18 #include <linux/fb.h> 19 #include <linux/slab.h> 20 21 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \ 22 defined(CONFIG_LCD_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 lcd power as well ... 26 */ 27 static int fb_notifier_callback(struct notifier_block *self, 28 unsigned long event, void *data) 29 { 30 struct lcd_device *ld; 31 struct fb_event *evdata = data; 32 33 /* If we aren't interested in this event, skip it immediately ... */ 34 switch (event) { 35 case FB_EVENT_BLANK: 36 case FB_EVENT_MODE_CHANGE: 37 case FB_EVENT_MODE_CHANGE_ALL: 38 case FB_EARLY_EVENT_BLANK: 39 case FB_R_EARLY_EVENT_BLANK: 40 break; 41 default: 42 return 0; 43 } 44 45 ld = container_of(self, struct lcd_device, fb_notif); 46 if (!ld->ops) 47 return 0; 48 49 mutex_lock(&ld->ops_lock); 50 if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) { 51 if (event == FB_EVENT_BLANK) { 52 if (ld->ops->set_power) 53 ld->ops->set_power(ld, *(int *)evdata->data); 54 } else if (event == FB_EARLY_EVENT_BLANK) { 55 if (ld->ops->early_set_power) 56 ld->ops->early_set_power(ld, 57 *(int *)evdata->data); 58 } else if (event == FB_R_EARLY_EVENT_BLANK) { 59 if (ld->ops->r_early_set_power) 60 ld->ops->r_early_set_power(ld, 61 *(int *)evdata->data); 62 } else { 63 if (ld->ops->set_mode) 64 ld->ops->set_mode(ld, evdata->data); 65 } 66 } 67 mutex_unlock(&ld->ops_lock); 68 return 0; 69 } 70 71 static int lcd_register_fb(struct lcd_device *ld) 72 { 73 memset(&ld->fb_notif, 0, sizeof(ld->fb_notif)); 74 ld->fb_notif.notifier_call = fb_notifier_callback; 75 return fb_register_client(&ld->fb_notif); 76 } 77 78 static void lcd_unregister_fb(struct lcd_device *ld) 79 { 80 fb_unregister_client(&ld->fb_notif); 81 } 82 #else 83 static int lcd_register_fb(struct lcd_device *ld) 84 { 85 return 0; 86 } 87 88 static inline void lcd_unregister_fb(struct lcd_device *ld) 89 { 90 } 91 #endif /* CONFIG_FB */ 92 93 static ssize_t lcd_power_show(struct device *dev, struct device_attribute *attr, 94 char *buf) 95 { 96 int rc; 97 struct lcd_device *ld = to_lcd_device(dev); 98 99 mutex_lock(&ld->ops_lock); 100 if (ld->ops && ld->ops->get_power) 101 rc = sprintf(buf, "%d\n", ld->ops->get_power(ld)); 102 else 103 rc = -ENXIO; 104 mutex_unlock(&ld->ops_lock); 105 106 return rc; 107 } 108 109 static ssize_t lcd_power_store(struct device *dev, 110 struct device_attribute *attr, const char *buf, size_t count) 111 { 112 int rc; 113 struct lcd_device *ld = to_lcd_device(dev); 114 unsigned long power; 115 116 rc = kstrtoul(buf, 0, &power); 117 if (rc) 118 return rc; 119 120 rc = -ENXIO; 121 122 mutex_lock(&ld->ops_lock); 123 if (ld->ops && ld->ops->set_power) { 124 pr_debug("set power to %lu\n", power); 125 ld->ops->set_power(ld, power); 126 rc = count; 127 } 128 mutex_unlock(&ld->ops_lock); 129 130 return rc; 131 } 132 static DEVICE_ATTR_RW(lcd_power); 133 134 static ssize_t contrast_show(struct device *dev, 135 struct device_attribute *attr, char *buf) 136 { 137 int rc = -ENXIO; 138 struct lcd_device *ld = to_lcd_device(dev); 139 140 mutex_lock(&ld->ops_lock); 141 if (ld->ops && ld->ops->get_contrast) 142 rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld)); 143 mutex_unlock(&ld->ops_lock); 144 145 return rc; 146 } 147 148 static ssize_t contrast_store(struct device *dev, 149 struct device_attribute *attr, const char *buf, size_t count) 150 { 151 int rc; 152 struct lcd_device *ld = to_lcd_device(dev); 153 unsigned long contrast; 154 155 rc = kstrtoul(buf, 0, &contrast); 156 if (rc) 157 return rc; 158 159 rc = -ENXIO; 160 161 mutex_lock(&ld->ops_lock); 162 if (ld->ops && ld->ops->set_contrast) { 163 pr_debug("set contrast to %lu\n", contrast); 164 ld->ops->set_contrast(ld, contrast); 165 rc = count; 166 } 167 mutex_unlock(&ld->ops_lock); 168 169 return rc; 170 } 171 static DEVICE_ATTR_RW(contrast); 172 173 static ssize_t max_contrast_show(struct device *dev, 174 struct device_attribute *attr, char *buf) 175 { 176 struct lcd_device *ld = to_lcd_device(dev); 177 178 return sprintf(buf, "%d\n", ld->props.max_contrast); 179 } 180 static DEVICE_ATTR_RO(max_contrast); 181 182 static struct class *lcd_class; 183 184 static void lcd_device_release(struct device *dev) 185 { 186 struct lcd_device *ld = to_lcd_device(dev); 187 kfree(ld); 188 } 189 190 static struct attribute *lcd_device_attrs[] = { 191 &dev_attr_lcd_power.attr, 192 &dev_attr_contrast.attr, 193 &dev_attr_max_contrast.attr, 194 NULL, 195 }; 196 ATTRIBUTE_GROUPS(lcd_device); 197 198 /** 199 * lcd_device_register - register a new object of lcd_device class. 200 * @name: the name of the new object(must be the same as the name of the 201 * respective framebuffer device). 202 * @devdata: an optional pointer to be stored in the device. The 203 * methods may retrieve it by using lcd_get_data(ld). 204 * @ops: the lcd operations structure. 205 * 206 * Creates and registers a new lcd device. Returns either an ERR_PTR() 207 * or a pointer to the newly allocated device. 208 */ 209 struct lcd_device *lcd_device_register(const char *name, struct device *parent, 210 void *devdata, struct lcd_ops *ops) 211 { 212 struct lcd_device *new_ld; 213 int rc; 214 215 pr_debug("lcd_device_register: name=%s\n", name); 216 217 new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL); 218 if (!new_ld) 219 return ERR_PTR(-ENOMEM); 220 221 mutex_init(&new_ld->ops_lock); 222 mutex_init(&new_ld->update_lock); 223 224 new_ld->dev.class = lcd_class; 225 new_ld->dev.parent = parent; 226 new_ld->dev.release = lcd_device_release; 227 dev_set_name(&new_ld->dev, "%s", name); 228 dev_set_drvdata(&new_ld->dev, devdata); 229 230 new_ld->ops = ops; 231 232 rc = device_register(&new_ld->dev); 233 if (rc) { 234 put_device(&new_ld->dev); 235 return ERR_PTR(rc); 236 } 237 238 rc = lcd_register_fb(new_ld); 239 if (rc) { 240 device_unregister(&new_ld->dev); 241 return ERR_PTR(rc); 242 } 243 244 return new_ld; 245 } 246 EXPORT_SYMBOL(lcd_device_register); 247 248 /** 249 * lcd_device_unregister - unregisters a object of lcd_device class. 250 * @ld: the lcd device object to be unregistered and freed. 251 * 252 * Unregisters a previously registered via lcd_device_register object. 253 */ 254 void lcd_device_unregister(struct lcd_device *ld) 255 { 256 if (!ld) 257 return; 258 259 mutex_lock(&ld->ops_lock); 260 ld->ops = NULL; 261 mutex_unlock(&ld->ops_lock); 262 lcd_unregister_fb(ld); 263 264 device_unregister(&ld->dev); 265 } 266 EXPORT_SYMBOL(lcd_device_unregister); 267 268 static void devm_lcd_device_release(struct device *dev, void *res) 269 { 270 struct lcd_device *lcd = *(struct lcd_device **)res; 271 272 lcd_device_unregister(lcd); 273 } 274 275 static int devm_lcd_device_match(struct device *dev, void *res, void *data) 276 { 277 struct lcd_device **r = res; 278 279 return *r == data; 280 } 281 282 /** 283 * devm_lcd_device_register - resource managed lcd_device_register() 284 * @dev: the device to register 285 * @name: the name of the device 286 * @parent: a pointer to the parent device 287 * @devdata: an optional pointer to be stored for private driver use 288 * @ops: the lcd operations structure 289 * 290 * @return a struct lcd on success, or an ERR_PTR on error 291 * 292 * Managed lcd_device_register(). The lcd_device returned from this function 293 * are automatically freed on driver detach. See lcd_device_register() 294 * for more information. 295 */ 296 struct lcd_device *devm_lcd_device_register(struct device *dev, 297 const char *name, struct device *parent, 298 void *devdata, struct lcd_ops *ops) 299 { 300 struct lcd_device **ptr, *lcd; 301 302 ptr = devres_alloc(devm_lcd_device_release, sizeof(*ptr), GFP_KERNEL); 303 if (!ptr) 304 return ERR_PTR(-ENOMEM); 305 306 lcd = lcd_device_register(name, parent, devdata, ops); 307 if (!IS_ERR(lcd)) { 308 *ptr = lcd; 309 devres_add(dev, ptr); 310 } else { 311 devres_free(ptr); 312 } 313 314 return lcd; 315 } 316 EXPORT_SYMBOL(devm_lcd_device_register); 317 318 /** 319 * devm_lcd_device_unregister - resource managed lcd_device_unregister() 320 * @dev: the device to unregister 321 * @ld: the lcd device to unregister 322 * 323 * Deallocated a lcd allocated with devm_lcd_device_register(). Normally 324 * this function will not need to be called and the resource management 325 * code will ensure that the resource is freed. 326 */ 327 void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld) 328 { 329 int rc; 330 331 rc = devres_release(dev, devm_lcd_device_release, 332 devm_lcd_device_match, ld); 333 WARN_ON(rc); 334 } 335 EXPORT_SYMBOL(devm_lcd_device_unregister); 336 337 338 static void __exit lcd_class_exit(void) 339 { 340 class_destroy(lcd_class); 341 } 342 343 static int __init lcd_class_init(void) 344 { 345 lcd_class = class_create(THIS_MODULE, "lcd"); 346 if (IS_ERR(lcd_class)) { 347 pr_warn("Unable to create backlight class; errno = %ld\n", 348 PTR_ERR(lcd_class)); 349 return PTR_ERR(lcd_class); 350 } 351 352 lcd_class->dev_groups = lcd_device_groups; 353 return 0; 354 } 355 356 /* 357 * if this is compiled into the kernel, we need to ensure that the 358 * class is registered before users of the class try to register lcd's 359 */ 360 postcore_initcall(lcd_class_init); 361 module_exit(lcd_class_exit); 362 363 MODULE_LICENSE("GPL"); 364 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 365 MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction"); 366