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 = -ENXIO; 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 mutex_lock(&ld->ops_lock); 120 if (ld->ops && ld->ops->set_power) { 121 pr_debug("set power to %lu\n", power); 122 ld->ops->set_power(ld, power); 123 rc = count; 124 } 125 mutex_unlock(&ld->ops_lock); 126 127 return rc; 128 } 129 130 static ssize_t lcd_show_contrast(struct device *dev, 131 struct device_attribute *attr, char *buf) 132 { 133 int rc = -ENXIO; 134 struct lcd_device *ld = to_lcd_device(dev); 135 136 mutex_lock(&ld->ops_lock); 137 if (ld->ops && ld->ops->get_contrast) 138 rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld)); 139 mutex_unlock(&ld->ops_lock); 140 141 return rc; 142 } 143 144 static ssize_t lcd_store_contrast(struct device *dev, 145 struct device_attribute *attr, const char *buf, size_t count) 146 { 147 int rc = -ENXIO; 148 struct lcd_device *ld = to_lcd_device(dev); 149 unsigned long contrast; 150 151 rc = kstrtoul(buf, 0, &contrast); 152 if (rc) 153 return rc; 154 155 mutex_lock(&ld->ops_lock); 156 if (ld->ops && ld->ops->set_contrast) { 157 pr_debug("set contrast to %lu\n", contrast); 158 ld->ops->set_contrast(ld, contrast); 159 rc = count; 160 } 161 mutex_unlock(&ld->ops_lock); 162 163 return rc; 164 } 165 166 static ssize_t lcd_show_max_contrast(struct device *dev, 167 struct device_attribute *attr, char *buf) 168 { 169 struct lcd_device *ld = to_lcd_device(dev); 170 171 return sprintf(buf, "%d\n", ld->props.max_contrast); 172 } 173 174 static struct class *lcd_class; 175 176 static void lcd_device_release(struct device *dev) 177 { 178 struct lcd_device *ld = to_lcd_device(dev); 179 kfree(ld); 180 } 181 182 static struct device_attribute lcd_device_attributes[] = { 183 __ATTR(lcd_power, 0644, lcd_show_power, lcd_store_power), 184 __ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast), 185 __ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL), 186 __ATTR_NULL, 187 }; 188 189 /** 190 * lcd_device_register - register a new object of lcd_device class. 191 * @name: the name of the new object(must be the same as the name of the 192 * respective framebuffer device). 193 * @devdata: an optional pointer to be stored in the device. The 194 * methods may retrieve it by using lcd_get_data(ld). 195 * @ops: the lcd operations structure. 196 * 197 * Creates and registers a new lcd device. Returns either an ERR_PTR() 198 * or a pointer to the newly allocated device. 199 */ 200 struct lcd_device *lcd_device_register(const char *name, struct device *parent, 201 void *devdata, struct lcd_ops *ops) 202 { 203 struct lcd_device *new_ld; 204 int rc; 205 206 pr_debug("lcd_device_register: name=%s\n", name); 207 208 new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL); 209 if (!new_ld) 210 return ERR_PTR(-ENOMEM); 211 212 mutex_init(&new_ld->ops_lock); 213 mutex_init(&new_ld->update_lock); 214 215 new_ld->dev.class = lcd_class; 216 new_ld->dev.parent = parent; 217 new_ld->dev.release = lcd_device_release; 218 dev_set_name(&new_ld->dev, name); 219 dev_set_drvdata(&new_ld->dev, devdata); 220 221 rc = device_register(&new_ld->dev); 222 if (rc) { 223 kfree(new_ld); 224 return ERR_PTR(rc); 225 } 226 227 rc = lcd_register_fb(new_ld); 228 if (rc) { 229 device_unregister(&new_ld->dev); 230 return ERR_PTR(rc); 231 } 232 233 new_ld->ops = ops; 234 235 return new_ld; 236 } 237 EXPORT_SYMBOL(lcd_device_register); 238 239 /** 240 * lcd_device_unregister - unregisters a object of lcd_device class. 241 * @ld: the lcd device object to be unregistered and freed. 242 * 243 * Unregisters a previously registered via lcd_device_register object. 244 */ 245 void lcd_device_unregister(struct lcd_device *ld) 246 { 247 if (!ld) 248 return; 249 250 mutex_lock(&ld->ops_lock); 251 ld->ops = NULL; 252 mutex_unlock(&ld->ops_lock); 253 lcd_unregister_fb(ld); 254 255 device_unregister(&ld->dev); 256 } 257 EXPORT_SYMBOL(lcd_device_unregister); 258 259 static void __exit lcd_class_exit(void) 260 { 261 class_destroy(lcd_class); 262 } 263 264 static int __init lcd_class_init(void) 265 { 266 lcd_class = class_create(THIS_MODULE, "lcd"); 267 if (IS_ERR(lcd_class)) { 268 pr_warn("Unable to create backlight class; errno = %ld\n", 269 PTR_ERR(lcd_class)); 270 return PTR_ERR(lcd_class); 271 } 272 273 lcd_class->dev_attrs = lcd_device_attributes; 274 return 0; 275 } 276 277 /* 278 * if this is compiled into the kernel, we need to ensure that the 279 * class is registered before users of the class try to register lcd's 280 */ 281 postcore_initcall(lcd_class_init); 282 module_exit(lcd_class_exit); 283 284 MODULE_LICENSE("GPL"); 285 MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 286 MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction"); 287