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