1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * LCD Lowlevel Control Abstraction |
4 | * |
5 | * Copyright (C) 2003,2004 Hewlett-Packard Company |
6 | * |
7 | */ |
8 | |
9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
10 | |
11 | #include <linux/module.h> |
12 | #include <linux/init.h> |
13 | #include <linux/device.h> |
14 | #include <linux/lcd.h> |
15 | #include <linux/notifier.h> |
16 | #include <linux/ctype.h> |
17 | #include <linux/err.h> |
18 | #include <linux/fb.h> |
19 | #include <linux/slab.h> |
20 | |
21 | #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \ |
22 | defined(CONFIG_LCD_CLASS_DEVICE_MODULE)) |
23 | /* This callback gets called when something important happens inside a |
24 | * framebuffer driver. We're looking if that important event is blanking, |
25 | * and if it is, we're switching lcd power as well ... |
26 | */ |
27 | static int fb_notifier_callback(struct notifier_block *self, |
28 | unsigned long event, void *data) |
29 | { |
30 | struct lcd_device *ld; |
31 | struct fb_event *evdata = data; |
32 | |
33 | ld = container_of(self, struct lcd_device, fb_notif); |
34 | if (!ld->ops) |
35 | return 0; |
36 | |
37 | mutex_lock(&ld->ops_lock); |
38 | if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) { |
39 | if (event == FB_EVENT_BLANK) { |
40 | if (ld->ops->set_power) |
41 | ld->ops->set_power(ld, *(int *)evdata->data); |
42 | } else { |
43 | if (ld->ops->set_mode) |
44 | ld->ops->set_mode(ld, evdata->data); |
45 | } |
46 | } |
47 | mutex_unlock(lock: &ld->ops_lock); |
48 | return 0; |
49 | } |
50 | |
51 | static int lcd_register_fb(struct lcd_device *ld) |
52 | { |
53 | memset(&ld->fb_notif, 0, sizeof(ld->fb_notif)); |
54 | ld->fb_notif.notifier_call = fb_notifier_callback; |
55 | return fb_register_client(nb: &ld->fb_notif); |
56 | } |
57 | |
58 | static void lcd_unregister_fb(struct lcd_device *ld) |
59 | { |
60 | fb_unregister_client(nb: &ld->fb_notif); |
61 | } |
62 | #else |
63 | static int lcd_register_fb(struct lcd_device *ld) |
64 | { |
65 | return 0; |
66 | } |
67 | |
68 | static inline void lcd_unregister_fb(struct lcd_device *ld) |
69 | { |
70 | } |
71 | #endif /* CONFIG_FB */ |
72 | |
73 | static ssize_t lcd_power_show(struct device *dev, struct device_attribute *attr, |
74 | char *buf) |
75 | { |
76 | int rc; |
77 | struct lcd_device *ld = to_lcd_device(dev); |
78 | |
79 | mutex_lock(&ld->ops_lock); |
80 | if (ld->ops && ld->ops->get_power) |
81 | rc = sprintf(buf, fmt: "%d\n" , ld->ops->get_power(ld)); |
82 | else |
83 | rc = -ENXIO; |
84 | mutex_unlock(lock: &ld->ops_lock); |
85 | |
86 | return rc; |
87 | } |
88 | |
89 | static ssize_t lcd_power_store(struct device *dev, |
90 | struct device_attribute *attr, const char *buf, size_t count) |
91 | { |
92 | int rc; |
93 | struct lcd_device *ld = to_lcd_device(dev); |
94 | unsigned long power; |
95 | |
96 | rc = kstrtoul(s: buf, base: 0, res: &power); |
97 | if (rc) |
98 | return rc; |
99 | |
100 | rc = -ENXIO; |
101 | |
102 | mutex_lock(&ld->ops_lock); |
103 | if (ld->ops && ld->ops->set_power) { |
104 | pr_debug("set power to %lu\n" , power); |
105 | ld->ops->set_power(ld, power); |
106 | rc = count; |
107 | } |
108 | mutex_unlock(lock: &ld->ops_lock); |
109 | |
110 | return rc; |
111 | } |
112 | static DEVICE_ATTR_RW(lcd_power); |
113 | |
114 | static ssize_t contrast_show(struct device *dev, |
115 | struct device_attribute *attr, char *buf) |
116 | { |
117 | int rc = -ENXIO; |
118 | struct lcd_device *ld = to_lcd_device(dev); |
119 | |
120 | mutex_lock(&ld->ops_lock); |
121 | if (ld->ops && ld->ops->get_contrast) |
122 | rc = sprintf(buf, fmt: "%d\n" , ld->ops->get_contrast(ld)); |
123 | mutex_unlock(lock: &ld->ops_lock); |
124 | |
125 | return rc; |
126 | } |
127 | |
128 | static ssize_t contrast_store(struct device *dev, |
129 | struct device_attribute *attr, const char *buf, size_t count) |
130 | { |
131 | int rc; |
132 | struct lcd_device *ld = to_lcd_device(dev); |
133 | unsigned long contrast; |
134 | |
135 | rc = kstrtoul(s: buf, base: 0, res: &contrast); |
136 | if (rc) |
137 | return rc; |
138 | |
139 | rc = -ENXIO; |
140 | |
141 | mutex_lock(&ld->ops_lock); |
142 | if (ld->ops && ld->ops->set_contrast) { |
143 | pr_debug("set contrast to %lu\n" , contrast); |
144 | ld->ops->set_contrast(ld, contrast); |
145 | rc = count; |
146 | } |
147 | mutex_unlock(lock: &ld->ops_lock); |
148 | |
149 | return rc; |
150 | } |
151 | static DEVICE_ATTR_RW(contrast); |
152 | |
153 | static ssize_t max_contrast_show(struct device *dev, |
154 | struct device_attribute *attr, char *buf) |
155 | { |
156 | struct lcd_device *ld = to_lcd_device(dev); |
157 | |
158 | return sprintf(buf, fmt: "%d\n" , ld->props.max_contrast); |
159 | } |
160 | static DEVICE_ATTR_RO(max_contrast); |
161 | |
162 | static struct class *lcd_class; |
163 | |
164 | static void lcd_device_release(struct device *dev) |
165 | { |
166 | struct lcd_device *ld = to_lcd_device(dev); |
167 | kfree(objp: ld); |
168 | } |
169 | |
170 | static struct attribute *lcd_device_attrs[] = { |
171 | &dev_attr_lcd_power.attr, |
172 | &dev_attr_contrast.attr, |
173 | &dev_attr_max_contrast.attr, |
174 | NULL, |
175 | }; |
176 | ATTRIBUTE_GROUPS(lcd_device); |
177 | |
178 | /** |
179 | * lcd_device_register - register a new object of lcd_device class. |
180 | * @name: the name of the new object(must be the same as the name of the |
181 | * respective framebuffer device). |
182 | * @parent: pointer to the parent's struct device . |
183 | * @devdata: an optional pointer to be stored in the device. The |
184 | * methods may retrieve it by using lcd_get_data(ld). |
185 | * @ops: the lcd operations structure. |
186 | * |
187 | * Creates and registers a new lcd device. Returns either an ERR_PTR() |
188 | * or a pointer to the newly allocated device. |
189 | */ |
190 | struct lcd_device *lcd_device_register(const char *name, struct device *parent, |
191 | void *devdata, struct lcd_ops *ops) |
192 | { |
193 | struct lcd_device *new_ld; |
194 | int rc; |
195 | |
196 | pr_debug("lcd_device_register: name=%s\n" , name); |
197 | |
198 | new_ld = kzalloc(size: sizeof(struct lcd_device), GFP_KERNEL); |
199 | if (!new_ld) |
200 | return ERR_PTR(error: -ENOMEM); |
201 | |
202 | mutex_init(&new_ld->ops_lock); |
203 | mutex_init(&new_ld->update_lock); |
204 | |
205 | new_ld->dev.class = lcd_class; |
206 | new_ld->dev.parent = parent; |
207 | new_ld->dev.release = lcd_device_release; |
208 | dev_set_name(dev: &new_ld->dev, name: "%s" , name); |
209 | dev_set_drvdata(dev: &new_ld->dev, data: devdata); |
210 | |
211 | new_ld->ops = ops; |
212 | |
213 | rc = device_register(dev: &new_ld->dev); |
214 | if (rc) { |
215 | put_device(dev: &new_ld->dev); |
216 | return ERR_PTR(error: rc); |
217 | } |
218 | |
219 | rc = lcd_register_fb(ld: new_ld); |
220 | if (rc) { |
221 | device_unregister(dev: &new_ld->dev); |
222 | return ERR_PTR(error: rc); |
223 | } |
224 | |
225 | return new_ld; |
226 | } |
227 | EXPORT_SYMBOL(lcd_device_register); |
228 | |
229 | /** |
230 | * lcd_device_unregister - unregisters a object of lcd_device class. |
231 | * @ld: the lcd device object to be unregistered and freed. |
232 | * |
233 | * Unregisters a previously registered via lcd_device_register object. |
234 | */ |
235 | void lcd_device_unregister(struct lcd_device *ld) |
236 | { |
237 | if (!ld) |
238 | return; |
239 | |
240 | mutex_lock(&ld->ops_lock); |
241 | ld->ops = NULL; |
242 | mutex_unlock(lock: &ld->ops_lock); |
243 | lcd_unregister_fb(ld); |
244 | |
245 | device_unregister(dev: &ld->dev); |
246 | } |
247 | EXPORT_SYMBOL(lcd_device_unregister); |
248 | |
249 | static void devm_lcd_device_release(struct device *dev, void *res) |
250 | { |
251 | struct lcd_device *lcd = *(struct lcd_device **)res; |
252 | |
253 | lcd_device_unregister(lcd); |
254 | } |
255 | |
256 | static int devm_lcd_device_match(struct device *dev, void *res, void *data) |
257 | { |
258 | struct lcd_device **r = res; |
259 | |
260 | return *r == data; |
261 | } |
262 | |
263 | /** |
264 | * devm_lcd_device_register - resource managed lcd_device_register() |
265 | * @dev: the device to register |
266 | * @name: the name of the device |
267 | * @parent: a pointer to the parent device |
268 | * @devdata: an optional pointer to be stored for private driver use |
269 | * @ops: the lcd operations structure |
270 | * |
271 | * @return a struct lcd on success, or an ERR_PTR on error |
272 | * |
273 | * Managed lcd_device_register(). The lcd_device returned from this function |
274 | * are automatically freed on driver detach. See lcd_device_register() |
275 | * for more information. |
276 | */ |
277 | struct lcd_device *devm_lcd_device_register(struct device *dev, |
278 | const char *name, struct device *parent, |
279 | void *devdata, struct lcd_ops *ops) |
280 | { |
281 | struct lcd_device **ptr, *lcd; |
282 | |
283 | ptr = devres_alloc(devm_lcd_device_release, sizeof(*ptr), GFP_KERNEL); |
284 | if (!ptr) |
285 | return ERR_PTR(error: -ENOMEM); |
286 | |
287 | lcd = lcd_device_register(name, parent, devdata, ops); |
288 | if (!IS_ERR(ptr: lcd)) { |
289 | *ptr = lcd; |
290 | devres_add(dev, res: ptr); |
291 | } else { |
292 | devres_free(res: ptr); |
293 | } |
294 | |
295 | return lcd; |
296 | } |
297 | EXPORT_SYMBOL(devm_lcd_device_register); |
298 | |
299 | /** |
300 | * devm_lcd_device_unregister - resource managed lcd_device_unregister() |
301 | * @dev: the device to unregister |
302 | * @ld: the lcd device to unregister |
303 | * |
304 | * Deallocated a lcd allocated with devm_lcd_device_register(). Normally |
305 | * this function will not need to be called and the resource management |
306 | * code will ensure that the resource is freed. |
307 | */ |
308 | void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld) |
309 | { |
310 | int rc; |
311 | |
312 | rc = devres_release(dev, release: devm_lcd_device_release, |
313 | match: devm_lcd_device_match, match_data: ld); |
314 | WARN_ON(rc); |
315 | } |
316 | EXPORT_SYMBOL(devm_lcd_device_unregister); |
317 | |
318 | |
319 | static void __exit lcd_class_exit(void) |
320 | { |
321 | class_destroy(cls: lcd_class); |
322 | } |
323 | |
324 | static int __init lcd_class_init(void) |
325 | { |
326 | lcd_class = class_create(name: "lcd" ); |
327 | if (IS_ERR(ptr: lcd_class)) { |
328 | pr_warn("Unable to create backlight class; errno = %ld\n" , |
329 | PTR_ERR(lcd_class)); |
330 | return PTR_ERR(ptr: lcd_class); |
331 | } |
332 | |
333 | lcd_class->dev_groups = lcd_device_groups; |
334 | return 0; |
335 | } |
336 | |
337 | /* |
338 | * if this is compiled into the kernel, we need to ensure that the |
339 | * class is registered before users of the class try to register lcd's |
340 | */ |
341 | postcore_initcall(lcd_class_init); |
342 | module_exit(lcd_class_exit); |
343 | |
344 | MODULE_LICENSE("GPL" ); |
345 | MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>" ); |
346 | MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction" ); |
347 | |