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/slab.h> 19 20 static DEFINE_MUTEX(lcd_dev_list_mutex); 21 static LIST_HEAD(lcd_dev_list); 22 23 static void lcd_notify_blank(struct lcd_device *ld, struct device *display_dev, 24 int power) 25 { 26 guard(mutex)(&ld->ops_lock); 27 28 if (!ld->ops || !ld->ops->set_power) 29 return; 30 if (ld->ops->controls_device && !ld->ops->controls_device(ld, display_dev)) 31 return; 32 33 ld->ops->set_power(ld, power); 34 } 35 36 void lcd_notify_blank_all(struct device *display_dev, int power) 37 { 38 struct lcd_device *ld; 39 40 guard(mutex)(&lcd_dev_list_mutex); 41 42 list_for_each_entry(ld, &lcd_dev_list, entry) 43 lcd_notify_blank(ld, display_dev, power); 44 } 45 EXPORT_SYMBOL(lcd_notify_blank_all); 46 47 static void lcd_notify_mode_change(struct lcd_device *ld, struct device *display_dev, 48 unsigned int width, unsigned int height) 49 { 50 guard(mutex)(&ld->ops_lock); 51 52 if (!ld->ops || !ld->ops->set_mode) 53 return; 54 if (ld->ops->controls_device && !ld->ops->controls_device(ld, display_dev)) 55 return; 56 57 ld->ops->set_mode(ld, width, height); 58 } 59 60 void lcd_notify_mode_change_all(struct device *display_dev, 61 unsigned int width, unsigned int height) 62 { 63 struct lcd_device *ld; 64 65 guard(mutex)(&lcd_dev_list_mutex); 66 67 list_for_each_entry(ld, &lcd_dev_list, entry) 68 lcd_notify_mode_change(ld, display_dev, width, height); 69 } 70 EXPORT_SYMBOL(lcd_notify_mode_change_all); 71 72 static ssize_t lcd_power_show(struct device *dev, struct device_attribute *attr, 73 char *buf) 74 { 75 int rc; 76 struct lcd_device *ld = to_lcd_device(dev); 77 78 mutex_lock(&ld->ops_lock); 79 if (ld->ops && ld->ops->get_power) 80 rc = sprintf(buf, "%d\n", ld->ops->get_power(ld)); 81 else 82 rc = -ENXIO; 83 mutex_unlock(&ld->ops_lock); 84 85 return rc; 86 } 87 88 static ssize_t lcd_power_store(struct device *dev, 89 struct device_attribute *attr, const char *buf, size_t count) 90 { 91 int rc; 92 struct lcd_device *ld = to_lcd_device(dev); 93 unsigned long power; 94 95 rc = kstrtoul(buf, 0, &power); 96 if (rc) 97 return rc; 98 99 rc = -ENXIO; 100 101 mutex_lock(&ld->ops_lock); 102 if (ld->ops && ld->ops->set_power) { 103 pr_debug("set power to %lu\n", power); 104 ld->ops->set_power(ld, power); 105 rc = count; 106 } 107 mutex_unlock(&ld->ops_lock); 108 109 return rc; 110 } 111 static DEVICE_ATTR_RW(lcd_power); 112 113 static ssize_t contrast_show(struct device *dev, 114 struct device_attribute *attr, char *buf) 115 { 116 int rc = -ENXIO; 117 struct lcd_device *ld = to_lcd_device(dev); 118 119 mutex_lock(&ld->ops_lock); 120 if (ld->ops && ld->ops->get_contrast) 121 rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld)); 122 mutex_unlock(&ld->ops_lock); 123 124 return rc; 125 } 126 127 static ssize_t contrast_store(struct device *dev, 128 struct device_attribute *attr, const char *buf, size_t count) 129 { 130 int rc; 131 struct lcd_device *ld = to_lcd_device(dev); 132 unsigned long contrast; 133 134 rc = kstrtoul(buf, 0, &contrast); 135 if (rc) 136 return rc; 137 138 rc = -ENXIO; 139 140 mutex_lock(&ld->ops_lock); 141 if (ld->ops && ld->ops->set_contrast) { 142 pr_debug("set contrast to %lu\n", contrast); 143 ld->ops->set_contrast(ld, contrast); 144 rc = count; 145 } 146 mutex_unlock(&ld->ops_lock); 147 148 return rc; 149 } 150 static DEVICE_ATTR_RW(contrast); 151 152 static ssize_t max_contrast_show(struct device *dev, 153 struct device_attribute *attr, char *buf) 154 { 155 struct lcd_device *ld = to_lcd_device(dev); 156 157 return sprintf(buf, "%d\n", ld->props.max_contrast); 158 } 159 static DEVICE_ATTR_RO(max_contrast); 160 161 static void lcd_device_release(struct device *dev) 162 { 163 struct lcd_device *ld = to_lcd_device(dev); 164 kfree(ld); 165 } 166 167 static struct attribute *lcd_device_attrs[] = { 168 &dev_attr_lcd_power.attr, 169 &dev_attr_contrast.attr, 170 &dev_attr_max_contrast.attr, 171 NULL, 172 }; 173 ATTRIBUTE_GROUPS(lcd_device); 174 175 static const struct class lcd_class = { 176 .name = "lcd", 177 .dev_groups = lcd_device_groups, 178 }; 179 180 /** 181 * lcd_device_register - register a new object of lcd_device class. 182 * @name: the name of the new object(must be the same as the name of the 183 * respective framebuffer device). 184 * @parent: pointer to the parent's struct device . 185 * @devdata: an optional pointer to be stored in the device. The 186 * methods may retrieve it by using lcd_get_data(ld). 187 * @ops: the lcd operations structure. 188 * 189 * Creates and registers a new lcd device. Returns either an ERR_PTR() 190 * or a pointer to the newly allocated device. 191 */ 192 struct lcd_device *lcd_device_register(const char *name, struct device *parent, 193 void *devdata, const struct lcd_ops *ops) 194 { 195 struct lcd_device *new_ld; 196 int rc; 197 198 pr_debug("lcd_device_register: name=%s\n", name); 199 200 new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL); 201 if (!new_ld) 202 return ERR_PTR(-ENOMEM); 203 204 mutex_init(&new_ld->ops_lock); 205 mutex_init(&new_ld->update_lock); 206 207 new_ld->dev.class = &lcd_class; 208 new_ld->dev.parent = parent; 209 new_ld->dev.release = lcd_device_release; 210 dev_set_name(&new_ld->dev, "%s", name); 211 dev_set_drvdata(&new_ld->dev, devdata); 212 213 new_ld->ops = ops; 214 215 rc = device_register(&new_ld->dev); 216 if (rc) { 217 put_device(&new_ld->dev); 218 return ERR_PTR(rc); 219 } 220 221 guard(mutex)(&lcd_dev_list_mutex); 222 list_add(&new_ld->entry, &lcd_dev_list); 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 guard(mutex)(&lcd_dev_list_mutex); 240 list_del(&ld->entry); 241 242 mutex_lock(&ld->ops_lock); 243 ld->ops = NULL; 244 mutex_unlock(&ld->ops_lock); 245 246 device_unregister(&ld->dev); 247 } 248 EXPORT_SYMBOL(lcd_device_unregister); 249 250 static void devm_lcd_device_release(struct device *dev, void *res) 251 { 252 struct lcd_device *lcd = *(struct lcd_device **)res; 253 254 lcd_device_unregister(lcd); 255 } 256 257 static int devm_lcd_device_match(struct device *dev, void *res, void *data) 258 { 259 struct lcd_device **r = res; 260 261 return *r == data; 262 } 263 264 /** 265 * devm_lcd_device_register - resource managed lcd_device_register() 266 * @dev: the device to register 267 * @name: the name of the device 268 * @parent: a pointer to the parent device 269 * @devdata: an optional pointer to be stored for private driver use 270 * @ops: the lcd operations structure 271 * 272 * @return a struct lcd on success, or an ERR_PTR on error 273 * 274 * Managed lcd_device_register(). The lcd_device returned from this function 275 * are automatically freed on driver detach. See lcd_device_register() 276 * for more information. 277 */ 278 struct lcd_device *devm_lcd_device_register(struct device *dev, 279 const char *name, struct device *parent, 280 void *devdata, const struct lcd_ops *ops) 281 { 282 struct lcd_device **ptr, *lcd; 283 284 ptr = devres_alloc(devm_lcd_device_release, sizeof(*ptr), GFP_KERNEL); 285 if (!ptr) 286 return ERR_PTR(-ENOMEM); 287 288 lcd = lcd_device_register(name, parent, devdata, ops); 289 if (!IS_ERR(lcd)) { 290 *ptr = lcd; 291 devres_add(dev, ptr); 292 } else { 293 devres_free(ptr); 294 } 295 296 return lcd; 297 } 298 EXPORT_SYMBOL(devm_lcd_device_register); 299 300 /** 301 * devm_lcd_device_unregister - resource managed lcd_device_unregister() 302 * @dev: the device to unregister 303 * @ld: the lcd device to unregister 304 * 305 * Deallocated a lcd allocated with devm_lcd_device_register(). Normally 306 * this function will not need to be called and the resource management 307 * code will ensure that the resource is freed. 308 */ 309 void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld) 310 { 311 int rc; 312 313 rc = devres_release(dev, devm_lcd_device_release, 314 devm_lcd_device_match, ld); 315 WARN_ON(rc); 316 } 317 EXPORT_SYMBOL(devm_lcd_device_unregister); 318 319 320 static void __exit lcd_class_exit(void) 321 { 322 class_unregister(&lcd_class); 323 } 324 325 static int __init lcd_class_init(void) 326 { 327 int ret; 328 329 ret = class_register(&lcd_class); 330 if (ret) { 331 pr_warn("Unable to create backlight class; errno = %d\n", ret); 332 return ret; 333 } 334 335 return 0; 336 } 337 338 /* 339 * if this is compiled into the kernel, we need to ensure that the 340 * class is registered before users of the class try to register lcd's 341 */ 342 postcore_initcall(lcd_class_init); 343 module_exit(lcd_class_exit); 344 345 MODULE_LICENSE("GPL"); 346 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 347 MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction"); 348