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