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