2 * LCD Lowlevel Control Abstraction
4 * Copyright (C) 2003,2004 Hewlett-Packard Company
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
18 #include <linux/slab.h>
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 ...
26 static int fb_notifier_callback(struct notifier_block *self,
27 unsigned long event, void *data)
29 struct lcd_device *ld;
30 struct fb_event *evdata = data;
32 /* If we aren't interested in this event, skip it immediately ... */
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:
44 ld = container_of(self, struct lcd_device, fb_notif);
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);
62 if (ld->ops->set_mode)
63 ld->ops->set_mode(ld, evdata->data);
66 mutex_unlock(&ld->ops_lock);
70 static int lcd_register_fb(struct lcd_device *ld)
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);
77 static void lcd_unregister_fb(struct lcd_device *ld)
79 fb_unregister_client(&ld->fb_notif);
82 static int lcd_register_fb(struct lcd_device *ld)
87 static inline void lcd_unregister_fb(struct lcd_device *ld)
90 #endif /* CONFIG_FB */
92 static ssize_t lcd_show_power(struct device *dev, struct device_attribute *attr,
96 struct lcd_device *ld = to_lcd_device(dev);
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));
103 mutex_unlock(&ld->ops_lock);
108 static ssize_t lcd_store_power(struct device *dev,
109 struct device_attribute *attr, const char *buf, size_t count)
112 struct lcd_device *ld = to_lcd_device(dev);
115 rc = kstrtoul(buf, 0, &power);
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);
127 mutex_unlock(&ld->ops_lock);
132 static ssize_t lcd_show_contrast(struct device *dev,
133 struct device_attribute *attr, char *buf)
136 struct lcd_device *ld = to_lcd_device(dev);
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);
146 static ssize_t lcd_store_contrast(struct device *dev,
147 struct device_attribute *attr, const char *buf, size_t count)
150 struct lcd_device *ld = to_lcd_device(dev);
151 unsigned long contrast;
153 rc = kstrtoul(buf, 0, &contrast);
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);
165 mutex_unlock(&ld->ops_lock);
170 static ssize_t lcd_show_max_contrast(struct device *dev,
171 struct device_attribute *attr, char *buf)
173 struct lcd_device *ld = to_lcd_device(dev);
175 return sprintf(buf, "%d\n", ld->props.max_contrast);
178 static struct class *lcd_class;
180 static void lcd_device_release(struct device *dev)
182 struct lcd_device *ld = to_lcd_device(dev);
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),
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.
201 * Creates and registers a new lcd device. Returns either an ERR_PTR()
202 * or a pointer to the newly allocated device.
204 struct lcd_device *lcd_device_register(const char *name, struct device *parent,
205 void *devdata, struct lcd_ops *ops)
207 struct lcd_device *new_ld;
210 pr_debug("lcd_device_register: name=%s\n", name);
212 new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL);
214 return ERR_PTR(-ENOMEM);
216 mutex_init(&new_ld->ops_lock);
217 mutex_init(&new_ld->update_lock);
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);
225 rc = device_register(&new_ld->dev);
231 rc = lcd_register_fb(new_ld);
233 device_unregister(&new_ld->dev);
241 EXPORT_SYMBOL(lcd_device_register);
244 * lcd_device_unregister - unregisters a object of lcd_device class.
245 * @ld: the lcd device object to be unregistered and freed.
247 * Unregisters a previously registered via lcd_device_register object.
249 void lcd_device_unregister(struct lcd_device *ld)
254 mutex_lock(&ld->ops_lock);
256 mutex_unlock(&ld->ops_lock);
257 lcd_unregister_fb(ld);
259 device_unregister(&ld->dev);
261 EXPORT_SYMBOL(lcd_device_unregister);
263 static void __exit lcd_class_exit(void)
265 class_destroy(lcd_class);
268 static int __init lcd_class_init(void)
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",
274 return PTR_ERR(lcd_class);
277 lcd_class->dev_attrs = lcd_device_attributes;
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
285 postcore_initcall(lcd_class_init);
286 module_exit(lcd_class_exit);
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");