1 /* 2 * LCD Lowlevel Control Abstraction 3 * 4 * Copyright (C) 2003,2004 Hewlett-Packard Company 5 * 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/module.h> 11 #include <linux/init.h> 12 #include <linux/device.h> 13 #include <linux/lcd.h> 14 #include <linux/notifier.h> 15 #include <linux/ctype.h> 16 #include <linux/err.h> 17 #include <linux/fb.h> 18 #include <linux/slab.h> 19 20 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \ 21 defined(CONFIG_LCD_CLASS_DEVICE_MODULE)) 22 /* This callback gets called when something important happens inside a 23 * framebuffer driver. We're looking if that important event is blanking, 24 * and if it is, we're switching lcd power as well ... 25 */ 26 static int fb_notifier_callback(struct notifier_block *self, 27 unsigned long event, void *data) 28 { 29 struct lcd_device *ld; 30 struct fb_event *evdata = data; 31 32 /* If we aren't interested in this event, skip it immediately ... */ 33 switch (event) { 34 case FB_EVENT_BLANK: 35 case FB_EVENT_MODE_CHANGE: 36 case FB_EVENT_MODE_CHANGE_ALL: 37 case FB_EARLY_EVENT_BLANK: 38 case FB_R_EARLY_EVENT_BLANK: 39 break; 40 default: 41 return 0; 42 } 43 44 ld = container_of(self, struct lcd_device, fb_notif); 45 if (!ld->ops) 46 return 0; 47 48 mutex_lock(&ld->ops_lock); 49 if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) { 50 if (event == FB_EVENT_BLANK) { 51 if (ld->ops->set_power) 52 ld->ops->set_power(ld, *(int *)evdata->data); 53 } else if (event == FB_EARLY_EVENT_BLANK) { 54 if (ld->ops->early_set_power) 55 ld->ops->early_set_power(ld, 56 *(int *)evdata->data); 57 } else if (event == FB_R_EARLY_EVENT_BLANK) { 58 if (ld->ops->r_early_set_power) 59 ld->ops->r_early_set_power(ld, 60 *(int *)evdata->data); 61 } else { 62 if (ld->ops->set_mode) 63 ld->ops->set_mode(ld, evdata->data); 64 } 65 } 66 mutex_unlock(&ld->ops_lock); 67 return 0; 68 } 69 70 static int lcd_register_fb(struct lcd_device *ld) 71 { 72 memset(&ld->fb_notif, 0, sizeof(ld->fb_notif)); 73 ld->fb_notif.notifier_call = fb_notifier_callback; 74 return fb_register_client(&ld->fb_notif); 75 } 76 77 static void lcd_unregister_fb(struct lcd_device *ld) 78 { 79 fb_unregister_client(&ld->fb_notif); 80 } 81 #else 82 static int lcd_register_fb(struct lcd_device *ld) 83 { 84 return 0; 85 } 86 87 static inline void lcd_unregister_fb(struct lcd_device *ld) 88 { 89 } 90 #endif /* CONFIG_FB */ 91 92 static ssize_t lcd_show_power(struct device *dev, struct device_attribute *attr, 93 char *buf) 94 { 95 int rc; 96 struct lcd_device *ld = to_lcd_device(dev); 97 98 mutex_lock(&ld->ops_lock); 99 if (ld->ops && ld->ops->get_power) 100 rc = sprintf(buf, "%d\n", ld->ops->get_power(ld)); 101 else 102 rc = -ENXIO; 103 mutex_unlock(&ld->ops_lock); 104 105 return rc; 106 } 107 108 static ssize_t lcd_store_power(struct device *dev, 109 struct device_attribute *attr, const char *buf, size_t count) 110 { 111 int rc; 112 struct lcd_device *ld = to_lcd_device(dev); 113 unsigned long power; 114 115 rc = kstrtoul(buf, 0, &power); 116 if (rc) 117 return rc; 118 119 rc = -ENXIO; 120 121 mutex_lock(&ld->ops_lock); 122 if (ld->ops && ld->ops->set_power) { 123 pr_debug("set power to %lu\n", power); 124 ld->ops->set_power(ld, power); 125 rc = count; 126 } 127 mutex_unlock(&ld->ops_lock); 128 129 return rc; 130 } 131 132 static ssize_t lcd_show_contrast(struct device *dev, 133 struct device_attribute *attr, char *buf) 134 { 135 int rc = -ENXIO; 136 struct lcd_device *ld = to_lcd_device(dev); 137 138 mutex_lock(&ld->ops_lock); 139 if (ld->ops && ld->ops->get_contrast) 140 rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld)); 141 mutex_unlock(&ld->ops_lock); 142 143 return rc; 144 } 145 146 static ssize_t lcd_store_contrast(struct device *dev, 147 struct device_attribute *attr, const char *buf, size_t count) 148 { 149 int rc; 150 struct lcd_device *ld = to_lcd_device(dev); 151 unsigned long contrast; 152 153 rc = kstrtoul(buf, 0, &contrast); 154 if (rc) 155 return rc; 156 157 rc = -ENXIO; 158 159 mutex_lock(&ld->ops_lock); 160 if (ld->ops && ld->ops->set_contrast) { 161 pr_debug("set contrast to %lu\n", contrast); 162 ld->ops->set_contrast(ld, contrast); 163 rc = count; 164 } 165 mutex_unlock(&ld->ops_lock); 166 167 return rc; 168 } 169 170 static ssize_t lcd_show_max_contrast(struct device *dev, 171 struct device_attribute *attr, char *buf) 172 { 173 struct lcd_device *ld = to_lcd_device(dev); 174 175 return sprintf(buf, "%d\n", ld->props.max_contrast); 176 } 177 178 static struct class *lcd_class; 179 180 static void lcd_device_release(struct device *dev) 181 { 182 struct lcd_device *ld = to_lcd_device(dev); 183 kfree(ld); 184 } 185 186 static struct device_attribute lcd_device_attributes[] = { 187 __ATTR(lcd_power, 0644, lcd_show_power, lcd_store_power), 188 __ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast), 189 __ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL), 190 __ATTR_NULL, 191 }; 192 193 /** 194 * lcd_device_register - register a new object of lcd_device class. 195 * @name: the name of the new object(must be the same as the name of the 196 * respective framebuffer device). 197 * @devdata: an optional pointer to be stored in the device. The 198 * methods may retrieve it by using lcd_get_data(ld). 199 * @ops: the lcd operations structure. 200 * 201 * Creates and registers a new lcd device. Returns either an ERR_PTR() 202 * or a pointer to the newly allocated device. 203 */ 204 struct lcd_device *lcd_device_register(const char *name, struct device *parent, 205 void *devdata, struct lcd_ops *ops) 206 { 207 struct lcd_device *new_ld; 208 int rc; 209 210 pr_debug("lcd_device_register: name=%s\n", name); 211 212 new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL); 213 if (!new_ld) 214 return ERR_PTR(-ENOMEM); 215 216 mutex_init(&new_ld->ops_lock); 217 mutex_init(&new_ld->update_lock); 218 219 new_ld->dev.class = lcd_class; 220 new_ld->dev.parent = parent; 221 new_ld->dev.release = lcd_device_release; 222 dev_set_name(&new_ld->dev, name); 223 dev_set_drvdata(&new_ld->dev, devdata); 224 225 rc = device_register(&new_ld->dev); 226 if (rc) { 227 kfree(new_ld); 228 return ERR_PTR(rc); 229 } 230 231 rc = lcd_register_fb(new_ld); 232 if (rc) { 233 device_unregister(&new_ld->dev); 234 return ERR_PTR(rc); 235 } 236 237 new_ld->ops = ops; 238 239 return new_ld; 240 } 241 EXPORT_SYMBOL(lcd_device_register); 242 243 /** 244 * lcd_device_unregister - unregisters a object of lcd_device class. 245 * @ld: the lcd device object to be unregistered and freed. 246 * 247 * Unregisters a previously registered via lcd_device_register object. 248 */ 249 void lcd_device_unregister(struct lcd_device *ld) 250 { 251 if (!ld) 252 return; 253 254 mutex_lock(&ld->ops_lock); 255 ld->ops = NULL; 256 mutex_unlock(&ld->ops_lock); 257 lcd_unregister_fb(ld); 258 259 device_unregister(&ld->dev); 260 } 261 EXPORT_SYMBOL(lcd_device_unregister); 262 263 static void __exit lcd_class_exit(void) 264 { 265 class_destroy(lcd_class); 266 } 267 268 static int __init lcd_class_init(void) 269 { 270 lcd_class = class_create(THIS_MODULE, "lcd"); 271 if (IS_ERR(lcd_class)) { 272 pr_warn("Unable to create backlight class; errno = %ld\n", 273 PTR_ERR(lcd_class)); 274 return PTR_ERR(lcd_class); 275 } 276 277 lcd_class->dev_attrs = lcd_device_attributes; 278 return 0; 279 } 280 281 /* 282 * if this is compiled into the kernel, we need to ensure that the 283 * class is registered before users of the class try to register lcd's 284 */ 285 postcore_initcall(lcd_class_init); 286 module_exit(lcd_class_exit); 287 288 MODULE_LICENSE("GPL"); 289 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 290 MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction"); 291