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 */ 24static 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 58static 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 65static void lcd_unregister_fb(struct lcd_device *ld) 66{ 67 fb_unregister_client(&ld->fb_notif); 68} 69#else 70static int lcd_register_fb(struct lcd_device *ld) 71{ 72 return 0; 73} 74 75static inline void lcd_unregister_fb(struct lcd_device *ld) 76{ 77} 78#endif /* CONFIG_FB */ 79 80static 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 96static 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 char *endp; 101 struct lcd_device *ld = to_lcd_device(dev); 102 int power = simple_strtoul(buf, &endp, 0); 103 size_t size = endp - buf; 104 105 if (isspace(*endp)) 106 size++; 107 if (size != count) 108 return -EINVAL; 109 110 mutex_lock(&ld->ops_lock); 111 if (ld->ops && ld->ops->set_power) { 112 pr_debug("lcd: set power to %d\n", power); 113 ld->ops->set_power(ld, power); 114 rc = count; 115 } 116 mutex_unlock(&ld->ops_lock); 117 118 return rc; 119} 120 121static ssize_t lcd_show_contrast(struct device *dev, 122 struct device_attribute *attr, char *buf) 123{ 124 int rc = -ENXIO; 125 struct lcd_device *ld = to_lcd_device(dev); 126 127 mutex_lock(&ld->ops_lock); 128 if (ld->ops && ld->ops->get_contrast) 129 rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld)); 130 mutex_unlock(&ld->ops_lock); 131 132 return rc; 133} 134 135static ssize_t lcd_store_contrast(struct device *dev, 136 struct device_attribute *attr, const char *buf, size_t count) 137{ 138 int rc = -ENXIO; 139 char *endp; 140 struct lcd_device *ld = to_lcd_device(dev); 141 int contrast = simple_strtoul(buf, &endp, 0); 142 size_t size = endp - buf; 143 144 if (isspace(*endp)) 145 size++; 146 if (size != count) 147 return -EINVAL; 148 149 mutex_lock(&ld->ops_lock); 150 if (ld->ops && ld->ops->set_contrast) { 151 pr_debug("lcd: set contrast to %d\n", contrast); 152 ld->ops->set_contrast(ld, contrast); 153 rc = count; 154 } 155 mutex_unlock(&ld->ops_lock); 156 157 return rc; 158} 159 160static ssize_t lcd_show_max_contrast(struct device *dev, 161 struct device_attribute *attr, char *buf) 162{ 163 struct lcd_device *ld = to_lcd_device(dev); 164 165 return sprintf(buf, "%d\n", ld->props.max_contrast); 166} 167 168static struct class *lcd_class; 169 170static void lcd_device_release(struct device *dev) 171{ 172 struct lcd_device *ld = to_lcd_device(dev); 173 kfree(ld); 174} 175 176static struct device_attribute lcd_device_attributes[] = { 177 __ATTR(lcd_power, 0644, lcd_show_power, lcd_store_power), 178 __ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast), 179 __ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL), 180 __ATTR_NULL, 181}; 182 183/** 184 * lcd_device_register - register a new object of lcd_device class. 185 * @name: the name of the new object(must be the same as the name of the 186 * respective framebuffer device). 187 * @devdata: an optional pointer to be stored in the device. The 188 * methods may retrieve it by using lcd_get_data(ld). 189 * @ops: the lcd operations structure. 190 * 191 * Creates and registers a new lcd device. Returns either an ERR_PTR() 192 * or a pointer to the newly allocated device. 193 */ 194struct lcd_device *lcd_device_register(const char *name, struct device *parent, 195 void *devdata, struct lcd_ops *ops) 196{ 197 struct lcd_device *new_ld; 198 int rc; 199 200 pr_debug("lcd_device_register: name=%s\n", name); 201 202 new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL); 203 if (!new_ld) 204 return ERR_PTR(-ENOMEM); 205 206 mutex_init(&new_ld->ops_lock); 207 mutex_init(&new_ld->update_lock); 208 209 new_ld->dev.class = lcd_class; 210 new_ld->dev.parent = parent; 211 new_ld->dev.release = lcd_device_release; 212 dev_set_name(&new_ld->dev, name); 213 dev_set_drvdata(&new_ld->dev, devdata); 214 215 rc = device_register(&new_ld->dev); 216 if (rc) { 217 kfree(new_ld); 218 return ERR_PTR(rc); 219 } 220 221 rc = lcd_register_fb(new_ld); 222 if (rc) { 223 device_unregister(&new_ld->dev); 224 return ERR_PTR(rc); 225 } 226 227 new_ld->ops = ops; 228 229 return new_ld; 230} 231EXPORT_SYMBOL(lcd_device_register); 232 233/** 234 * lcd_device_unregister - unregisters a object of lcd_device class. 235 * @ld: the lcd device object to be unregistered and freed. 236 * 237 * Unregisters a previously registered via lcd_device_register object. 238 */ 239void lcd_device_unregister(struct lcd_device *ld) 240{ 241 if (!ld) 242 return; 243 244 mutex_lock(&ld->ops_lock); 245 ld->ops = NULL; 246 mutex_unlock(&ld->ops_lock); 247 lcd_unregister_fb(ld); 248 249 device_unregister(&ld->dev); 250} 251EXPORT_SYMBOL(lcd_device_unregister); 252 253static void __exit lcd_class_exit(void) 254{ 255 class_destroy(lcd_class); 256} 257 258static int __init lcd_class_init(void) 259{ 260 lcd_class = class_create(THIS_MODULE, "lcd"); 261 if (IS_ERR(lcd_class)) { 262 printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n", 263 PTR_ERR(lcd_class)); 264 return PTR_ERR(lcd_class); 265 } 266 267 lcd_class->dev_attrs = lcd_device_attributes; 268 return 0; 269} 270 271/* 272 * if this is compiled into the kernel, we need to ensure that the 273 * class is registered before users of the class try to register lcd's 274 */ 275postcore_initcall(lcd_class_init); 276module_exit(lcd_class_exit); 277 278MODULE_LICENSE("GPL"); 279MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>"); 280MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction"); 281