1 /* 2 * LCD Lowlevel Control Abstraction 3 * 4 * Copyright (C) 2003,2004 Hewlett-Packard Company 5 * 6 */ 7 8 #include <linux/module.h> 9 #include <linux/init.h> 10 #include <linux/device.h> 11 #include <linux/lcd.h> 12 #include <linux/notifier.h> 13 #include <linux/ctype.h> 14 #include <linux/err.h> 15 #include <linux/fb.h> 16 17 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \ 18 defined(CONFIG_LCD_CLASS_DEVICE_MODULE)) 19 /* This callback gets called when something important happens inside a 20 * framebuffer driver. We're looking if that important event is blanking, 21 * and if it is, we're switching lcd power as well ... 22 */ 23 static int fb_notifier_callback(struct notifier_block *self, 24 unsigned long event, void *data) 25 { 26 struct lcd_device *ld; 27 struct fb_event *evdata = data; 28 29 /* If we aren't interested in this event, skip it immediately ... */ 30 if (event != FB_EVENT_BLANK) 31 return 0; 32 33 ld = container_of(self, struct lcd_device, fb_notif); 34 mutex_lock(&ld->ops_lock); 35 if (ld->ops) 36 if (!ld->ops->check_fb || ld->ops->check_fb(evdata->info)) 37 ld->ops->set_power(ld, *(int *)evdata->data); 38 mutex_unlock(&ld->ops_lock); 39 return 0; 40 } 41 42 static int lcd_register_fb(struct lcd_device *ld) 43 { 44 memset(&ld->fb_notif, 0, sizeof(&ld->fb_notif)); 45 ld->fb_notif.notifier_call = fb_notifier_callback; 46 return fb_register_client(&ld->fb_notif); 47 } 48 49 static void lcd_unregister_fb(struct lcd_device *ld) 50 { 51 fb_unregister_client(&ld->fb_notif); 52 } 53 #else 54 static int lcd_register_fb(struct lcd_device *ld) 55 { 56 return 0; 57 } 58 59 static inline void lcd_unregister_fb(struct lcd_device *ld) 60 { 61 } 62 #endif /* CONFIG_FB */ 63 64 static ssize_t lcd_show_power(struct class_device *cdev, char *buf) 65 { 66 int rc; 67 struct lcd_device *ld = to_lcd_device(cdev); 68 69 mutex_lock(&ld->ops_lock); 70 if (ld->ops && ld->ops->get_power) 71 rc = sprintf(buf, "%d\n", ld->ops->get_power(ld)); 72 else 73 rc = -ENXIO; 74 mutex_unlock(&ld->ops_lock); 75 76 return rc; 77 } 78 79 static ssize_t lcd_store_power(struct class_device *cdev, const char *buf, size_t count) 80 { 81 int rc = -ENXIO; 82 char *endp; 83 struct lcd_device *ld = to_lcd_device(cdev); 84 int power = simple_strtoul(buf, &endp, 0); 85 size_t size = endp - buf; 86 87 if (*endp && isspace(*endp)) 88 size++; 89 if (size != count) 90 return -EINVAL; 91 92 mutex_lock(&ld->ops_lock); 93 if (ld->ops && ld->ops->set_power) { 94 pr_debug("lcd: set power to %d\n", power); 95 ld->ops->set_power(ld, power); 96 rc = count; 97 } 98 mutex_unlock(&ld->ops_lock); 99 100 return rc; 101 } 102 103 static ssize_t lcd_show_contrast(struct class_device *cdev, char *buf) 104 { 105 int rc = -ENXIO; 106 struct lcd_device *ld = to_lcd_device(cdev); 107 108 mutex_lock(&ld->ops_lock); 109 if (ld->ops && ld->ops->get_contrast) 110 rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld)); 111 mutex_unlock(&ld->ops_lock); 112 113 return rc; 114 } 115 116 static ssize_t lcd_store_contrast(struct class_device *cdev, const char *buf, size_t count) 117 { 118 int rc = -ENXIO; 119 char *endp; 120 struct lcd_device *ld = to_lcd_device(cdev); 121 int contrast = simple_strtoul(buf, &endp, 0); 122 size_t size = endp - buf; 123 124 if (*endp && isspace(*endp)) 125 size++; 126 if (size != count) 127 return -EINVAL; 128 129 mutex_lock(&ld->ops_lock); 130 if (ld->ops && ld->ops->set_contrast) { 131 pr_debug("lcd: set contrast to %d\n", contrast); 132 ld->ops->set_contrast(ld, contrast); 133 rc = count; 134 } 135 mutex_unlock(&ld->ops_lock); 136 137 return rc; 138 } 139 140 static ssize_t lcd_show_max_contrast(struct class_device *cdev, char *buf) 141 { 142 struct lcd_device *ld = to_lcd_device(cdev); 143 144 return sprintf(buf, "%d\n", ld->props.max_contrast); 145 } 146 147 static void lcd_class_release(struct class_device *dev) 148 { 149 struct lcd_device *ld = to_lcd_device(dev); 150 kfree(ld); 151 } 152 153 static struct class lcd_class = { 154 .name = "lcd", 155 .release = lcd_class_release, 156 }; 157 158 #define DECLARE_ATTR(_name,_mode,_show,_store) \ 159 { \ 160 .attr = { .name = __stringify(_name), .mode = _mode, .owner = THIS_MODULE }, \ 161 .show = _show, \ 162 .store = _store, \ 163 } 164 165 static const struct class_device_attribute lcd_class_device_attributes[] = { 166 DECLARE_ATTR(power, 0644, lcd_show_power, lcd_store_power), 167 DECLARE_ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast), 168 DECLARE_ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL), 169 }; 170 171 /** 172 * lcd_device_register - register a new object of lcd_device class. 173 * @name: the name of the new object(must be the same as the name of the 174 * respective framebuffer device). 175 * @devdata: an optional pointer to be stored in the class_device. The 176 * methods may retrieve it by using class_get_devdata(ld->class_dev). 177 * @ops: the lcd operations structure. 178 * 179 * Creates and registers a new lcd class_device. Returns either an ERR_PTR() 180 * or a pointer to the newly allocated device. 181 */ 182 struct lcd_device *lcd_device_register(const char *name, void *devdata, 183 struct lcd_ops *ops) 184 { 185 int i, rc; 186 struct lcd_device *new_ld; 187 188 pr_debug("lcd_device_register: name=%s\n", name); 189 190 new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL); 191 if (!new_ld) 192 return ERR_PTR(-ENOMEM); 193 194 mutex_init(&new_ld->ops_lock); 195 mutex_init(&new_ld->update_lock); 196 new_ld->ops = ops; 197 new_ld->class_dev.class = &lcd_class; 198 strlcpy(new_ld->class_dev.class_id, name, KOBJ_NAME_LEN); 199 class_set_devdata(&new_ld->class_dev, devdata); 200 201 rc = class_device_register(&new_ld->class_dev); 202 if (rc) { 203 kfree(new_ld); 204 return ERR_PTR(rc); 205 } 206 207 rc = lcd_register_fb(new_ld); 208 if (rc) { 209 class_device_unregister(&new_ld->class_dev); 210 return ERR_PTR(rc); 211 } 212 213 for (i = 0; i < ARRAY_SIZE(lcd_class_device_attributes); i++) { 214 rc = class_device_create_file(&new_ld->class_dev, 215 &lcd_class_device_attributes[i]); 216 if (rc) { 217 while (--i >= 0) 218 class_device_remove_file(&new_ld->class_dev, 219 &lcd_class_device_attributes[i]); 220 class_device_unregister(&new_ld->class_dev); 221 /* No need to kfree(new_ld) since release() method was called */ 222 return ERR_PTR(rc); 223 } 224 } 225 226 return new_ld; 227 } 228 EXPORT_SYMBOL(lcd_device_register); 229 230 /** 231 * lcd_device_unregister - unregisters a object of lcd_device class. 232 * @ld: the lcd device object to be unregistered and freed. 233 * 234 * Unregisters a previously registered via lcd_device_register object. 235 */ 236 void lcd_device_unregister(struct lcd_device *ld) 237 { 238 int i; 239 240 if (!ld) 241 return; 242 243 pr_debug("lcd_device_unregister: name=%s\n", ld->class_dev.class_id); 244 245 for (i = 0; i < ARRAY_SIZE(lcd_class_device_attributes); i++) 246 class_device_remove_file(&ld->class_dev, 247 &lcd_class_device_attributes[i]); 248 249 mutex_lock(&ld->ops_lock); 250 ld->ops = NULL; 251 mutex_unlock(&ld->ops_lock); 252 lcd_unregister_fb(ld); 253 class_device_unregister(&ld->class_dev); 254 } 255 EXPORT_SYMBOL(lcd_device_unregister); 256 257 static void __exit lcd_class_exit(void) 258 { 259 class_unregister(&lcd_class); 260 } 261 262 static int __init lcd_class_init(void) 263 { 264 return class_register(&lcd_class); 265 } 266 267 /* 268 * if this is compiled into the kernel, we need to ensure that the 269 * class is registered before users of the class try to register lcd's 270 */ 271 postcore_initcall(lcd_class_init); 272 module_exit(lcd_class_exit); 273 274 MODULE_LICENSE("GPL"); 275 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 276 MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction"); 277