Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
17#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
18 defined(CONFIG_LCD_CLASS_DEVICE_MODULE))
19/* This callback gets called when something important happens inside a
20 * framebuffer driver. We're looking if that important event is blanking,
21 * and if it is, we're switching lcd power as well ...
22 */
23static int fb_notifier_callback(struct notifier_block *self,
24 unsigned long event, void *data)
25{
26 struct lcd_device *ld;
27 struct fb_event *evdata = data;
28
29 /* If we aren't interested in this event, skip it immediately ... */
30 switch (event) {
31 case FB_EVENT_BLANK:
32 case FB_EVENT_MODE_CHANGE:
33 case FB_EVENT_MODE_CHANGE_ALL:
34 break;
35 default:
36 return 0;
37 }
38
39 ld = container_of(self, struct lcd_device, fb_notif);
40 if (!ld->ops)
41 return 0;
42
43 mutex_lock(&ld->ops_lock);
44 if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) {
45 if (event == FB_EVENT_BLANK) {
46 if (ld->ops->set_power)
47 ld->ops->set_power(ld, *(int *)evdata->data);
48 } else {
49 if (ld->ops->set_mode)
50 ld->ops->set_mode(ld, evdata->data);
51 }
52 }
53 mutex_unlock(&ld->ops_lock);
54 return 0;
55}
56
57static int lcd_register_fb(struct lcd_device *ld)
58{
59 memset(&ld->fb_notif, 0, sizeof(&ld->fb_notif));
60 ld->fb_notif.notifier_call = fb_notifier_callback;
61 return fb_register_client(&ld->fb_notif);
62}
63
64static void lcd_unregister_fb(struct lcd_device *ld)
65{
66 fb_unregister_client(&ld->fb_notif);
67}
68#else
69static int lcd_register_fb(struct lcd_device *ld)
70{
71 return 0;
72}
73
74static inline void lcd_unregister_fb(struct lcd_device *ld)
75{
76}
77#endif /* CONFIG_FB */
78
79static ssize_t lcd_show_power(struct device *dev, struct device_attribute *attr,
80 char *buf)
81{
82 int rc;
83 struct lcd_device *ld = to_lcd_device(dev);
84
85 mutex_lock(&ld->ops_lock);
86 if (ld->ops && ld->ops->get_power)
87 rc = sprintf(buf, "%d\n", ld->ops->get_power(ld));
88 else
89 rc = -ENXIO;
90 mutex_unlock(&ld->ops_lock);
91
92 return rc;
93}
94
95static ssize_t lcd_store_power(struct device *dev,
96 struct device_attribute *attr, const char *buf, size_t count)
97{
98 int rc = -ENXIO;
99 char *endp;
100 struct lcd_device *ld = to_lcd_device(dev);
101 int power = simple_strtoul(buf, &endp, 0);
102 size_t size = endp - buf;
103
104 if (*endp && isspace(*endp))
105 size++;
106 if (size != count)
107 return -EINVAL;
108
109 mutex_lock(&ld->ops_lock);
110 if (ld->ops && ld->ops->set_power) {
111 pr_debug("lcd: set power to %d\n", power);
112 ld->ops->set_power(ld, power);
113 rc = count;
114 }
115 mutex_unlock(&ld->ops_lock);
116
117 return rc;
118}
119
120static ssize_t lcd_show_contrast(struct device *dev,
121 struct device_attribute *attr, char *buf)
122{
123 int rc = -ENXIO;
124 struct lcd_device *ld = to_lcd_device(dev);
125
126 mutex_lock(&ld->ops_lock);
127 if (ld->ops && ld->ops->get_contrast)
128 rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld));
129 mutex_unlock(&ld->ops_lock);
130
131 return rc;
132}
133
134static ssize_t lcd_store_contrast(struct device *dev,
135 struct device_attribute *attr, const char *buf, size_t count)
136{
137 int rc = -ENXIO;
138 char *endp;
139 struct lcd_device *ld = to_lcd_device(dev);
140 int contrast = simple_strtoul(buf, &endp, 0);
141 size_t size = endp - buf;
142
143 if (*endp && isspace(*endp))
144 size++;
145 if (size != count)
146 return -EINVAL;
147
148 mutex_lock(&ld->ops_lock);
149 if (ld->ops && ld->ops->set_contrast) {
150 pr_debug("lcd: set contrast to %d\n", contrast);
151 ld->ops->set_contrast(ld, contrast);
152 rc = count;
153 }
154 mutex_unlock(&ld->ops_lock);
155
156 return rc;
157}
158
159static ssize_t lcd_show_max_contrast(struct device *dev,
160 struct device_attribute *attr, char *buf)
161{
162 struct lcd_device *ld = to_lcd_device(dev);
163
164 return sprintf(buf, "%d\n", ld->props.max_contrast);
165}
166
167static struct class *lcd_class;
168
169static void lcd_device_release(struct device *dev)
170{
171 struct lcd_device *ld = to_lcd_device(dev);
172 kfree(ld);
173}
174
175static struct device_attribute lcd_device_attributes[] = {
176 __ATTR(lcd_power, 0644, lcd_show_power, lcd_store_power),
177 __ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast),
178 __ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL),
179 __ATTR_NULL,
180};
181
182/**
183 * lcd_device_register - register a new object of lcd_device class.
184 * @name: the name of the new object(must be the same as the name of the
185 * respective framebuffer device).
186 * @devdata: an optional pointer to be stored in the device. The
187 * methods may retrieve it by using lcd_get_data(ld).
188 * @ops: the lcd operations structure.
189 *
190 * Creates and registers a new lcd device. Returns either an ERR_PTR()
191 * or a pointer to the newly allocated device.
192 */
193struct lcd_device *lcd_device_register(const char *name, struct device *parent,
194 void *devdata, struct lcd_ops *ops)
195{
196 struct lcd_device *new_ld;
197 int rc;
198
199 pr_debug("lcd_device_register: name=%s\n", name);
200
201 new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL);
202 if (!new_ld)
203 return ERR_PTR(-ENOMEM);
204
205 mutex_init(&new_ld->ops_lock);
206 mutex_init(&new_ld->update_lock);
207
208 new_ld->dev.class = lcd_class;
209 new_ld->dev.parent = parent;
210 new_ld->dev.release = lcd_device_release;
211 dev_set_name(&new_ld->dev, name);
212 dev_set_drvdata(&new_ld->dev, devdata);
213
214 rc = device_register(&new_ld->dev);
215 if (rc) {
216 kfree(new_ld);
217 return ERR_PTR(rc);
218 }
219
220 rc = lcd_register_fb(new_ld);
221 if (rc) {
222 device_unregister(&new_ld->dev);
223 return ERR_PTR(rc);
224 }
225
226 new_ld->ops = ops;
227
228 return new_ld;
229}
230EXPORT_SYMBOL(lcd_device_register);
231
232/**
233 * lcd_device_unregister - unregisters a object of lcd_device class.
234 * @ld: the lcd device object to be unregistered and freed.
235 *
236 * Unregisters a previously registered via lcd_device_register object.
237 */
238void lcd_device_unregister(struct lcd_device *ld)
239{
240 if (!ld)
241 return;
242
243 mutex_lock(&ld->ops_lock);
244 ld->ops = NULL;
245 mutex_unlock(&ld->ops_lock);
246 lcd_unregister_fb(ld);
247
248 device_unregister(&ld->dev);
249}
250EXPORT_SYMBOL(lcd_device_unregister);
251
252static void __exit lcd_class_exit(void)
253{
254 class_destroy(lcd_class);
255}
256
257static int __init lcd_class_init(void)
258{
259 lcd_class = class_create(THIS_MODULE, "lcd");
260 if (IS_ERR(lcd_class)) {
261 printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",
262 PTR_ERR(lcd_class));
263 return PTR_ERR(lcd_class);
264 }
265
266 lcd_class->dev_attrs = lcd_device_attributes;
267 return 0;
268}
269
270/*
271 * if this is compiled into the kernel, we need to ensure that the
272 * class is registered before users of the class try to register lcd's
273 */
274postcore_initcall(lcd_class_init);
275module_exit(lcd_class_exit);
276
277MODULE_LICENSE("GPL");
278MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
279MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");