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