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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 | /* * Backlight Lowlevel Control Abstraction * * Copyright (C) 2003,2004 Hewlett-Packard Company * */ #include <linux/module.h> #include <linux/init.h> #include <linux/device.h> #include <linux/backlight.h> #include <linux/notifier.h> #include <linux/ctype.h> #include <linux/err.h> #include <linux/fb.h> static ssize_t backlight_show_power(struct class_device *cdev, char *buf) { int rc; struct backlight_device *bd = to_backlight_device(cdev); down(&bd->sem); if (likely(bd->props && bd->props->get_power)) rc = sprintf(buf, "%d\n", bd->props->get_power(bd)); else rc = -ENXIO; up(&bd->sem); return rc; } static ssize_t backlight_store_power(struct class_device *cdev, const char *buf, size_t count) { int rc, power; char *endp; struct backlight_device *bd = to_backlight_device(cdev); power = simple_strtoul(buf, &endp, 0); if (*endp && !isspace(*endp)) return -EINVAL; down(&bd->sem); if (likely(bd->props && bd->props->set_power)) { pr_debug("backlight: set power to %d\n", power); bd->props->set_power(bd, power); rc = count; } else rc = -ENXIO; up(&bd->sem); return rc; } static ssize_t backlight_show_brightness(struct class_device *cdev, char *buf) { int rc; struct backlight_device *bd = to_backlight_device(cdev); down(&bd->sem); if (likely(bd->props && bd->props->get_brightness)) rc = sprintf(buf, "%d\n", bd->props->get_brightness(bd)); else rc = -ENXIO; up(&bd->sem); return rc; } static ssize_t backlight_store_brightness(struct class_device *cdev, const char *buf, size_t count) { int rc, brightness; char *endp; struct backlight_device *bd = to_backlight_device(cdev); brightness = simple_strtoul(buf, &endp, 0); if (*endp && !isspace(*endp)) return -EINVAL; down(&bd->sem); if (likely(bd->props && bd->props->set_brightness)) { pr_debug("backlight: set brightness to %d\n", brightness); bd->props->set_brightness(bd, brightness); rc = count; } else rc = -ENXIO; up(&bd->sem); return rc; } static ssize_t backlight_show_max_brightness(struct class_device *cdev, char *buf) { int rc; struct backlight_device *bd = to_backlight_device(cdev); down(&bd->sem); if (likely(bd->props)) rc = sprintf(buf, "%d\n", bd->props->max_brightness); else rc = -ENXIO; up(&bd->sem); return rc; } static void backlight_class_release(struct class_device *dev) { struct backlight_device *bd = to_backlight_device(dev); kfree(bd); } static struct class backlight_class = { .name = "backlight", .release = backlight_class_release, }; #define DECLARE_ATTR(_name,_mode,_show,_store) \ { \ .attr = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE }, \ .show = _show, \ .store = _store, \ } static struct class_device_attribute bl_class_device_attributes[] = { DECLARE_ATTR(power, 0644, backlight_show_power, backlight_store_power), DECLARE_ATTR(brightness, 0644, backlight_show_brightness, backlight_store_brightness), DECLARE_ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL), }; /* This callback gets called when something important happens inside a * framebuffer driver. We're looking if that important event is blanking, * and if it is, we're switching backlight power as well ... */ static int fb_notifier_callback(struct notifier_block *self, unsigned long event, void *data) { struct backlight_device *bd; struct fb_event *evdata =(struct fb_event *)data; /* If we aren't interested in this event, skip it immediately ... */ if (event != FB_EVENT_BLANK) return 0; bd = container_of(self, struct backlight_device, fb_notif); down(&bd->sem); if (bd->props) if (!bd->props->check_fb || bd->props->check_fb(evdata->info)) bd->props->set_power(bd, *(int *)evdata->data); up(&bd->sem); return 0; } /** * backlight_device_register - create and register a new object of * backlight_device class. * @name: the name of the new object(must be the same as the name of the * respective framebuffer device). * @devdata: an optional pointer to be stored in the class_device. The * methods may retrieve it by using class_get_devdata(&bd->class_dev). * @bp: the backlight properties structure. * * Creates and registers new backlight class_device. Returns either an * ERR_PTR() or a pointer to the newly allocated device. */ struct backlight_device *backlight_device_register(const char *name, void *devdata, struct backlight_properties *bp) { int i, rc; struct backlight_device *new_bd; pr_debug("backlight_device_alloc: name=%s\n", name); new_bd = kmalloc(sizeof(struct backlight_device), GFP_KERNEL); if (unlikely(!new_bd)) return ERR_PTR(-ENOMEM); init_MUTEX(&new_bd->sem); new_bd->props = bp; memset(&new_bd->class_dev, 0, sizeof(new_bd->class_dev)); new_bd->class_dev.class = &backlight_class; strlcpy(new_bd->class_dev.class_id, name, KOBJ_NAME_LEN); class_set_devdata(&new_bd->class_dev, devdata); rc = class_device_register(&new_bd->class_dev); if (unlikely(rc)) { error: kfree(new_bd); return ERR_PTR(rc); } memset(&new_bd->fb_notif, 0, sizeof(new_bd->fb_notif)); new_bd->fb_notif.notifier_call = fb_notifier_callback; rc = fb_register_client(&new_bd->fb_notif); if (unlikely(rc)) goto error; for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++) { rc = class_device_create_file(&new_bd->class_dev, &bl_class_device_attributes[i]); if (unlikely(rc)) { while (--i >= 0) class_device_remove_file(&new_bd->class_dev, &bl_class_device_attributes[i]); class_device_unregister(&new_bd->class_dev); /* No need to kfree(new_bd) since release() method was called */ return ERR_PTR(rc); } } return new_bd; } EXPORT_SYMBOL(backlight_device_register); /** * backlight_device_unregister - unregisters a backlight device object. * @bd: the backlight device object to be unregistered and freed. * * Unregisters a previously registered via backlight_device_register object. */ void backlight_device_unregister(struct backlight_device *bd) { int i; if (!bd) return; pr_debug("backlight_device_unregister: name=%s\n", bd->class_dev.class_id); for (i = 0; i < ARRAY_SIZE(bl_class_device_attributes); i++) class_device_remove_file(&bd->class_dev, &bl_class_device_attributes[i]); down(&bd->sem); bd->props = NULL; up(&bd->sem); fb_unregister_client(&bd->fb_notif); class_device_unregister(&bd->class_dev); } EXPORT_SYMBOL(backlight_device_unregister); static void __exit backlight_class_exit(void) { class_unregister(&backlight_class); } static int __init backlight_class_init(void) { return class_register(&backlight_class); } /* * if this is compiled into the kernel, we need to ensure that the * class is registered before users of the class try to register lcd's */ postcore_initcall(backlight_class_init); module_exit(backlight_class_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction"); |