1/*
2 * LCD Lowlevel Control Abstraction
3 *
4 * Copyright (C) 2003,2004 Hewlett-Packard Company
5 *
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
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>
17#include <linux/fb.h>
18#include <linux/slab.h>
19
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 ...
25 */
26static int fb_notifier_callback(struct notifier_block *self,
27				 unsigned long event, void *data)
28{
29	struct lcd_device *ld;
30	struct fb_event *evdata = data;
31
32	/* If we aren't interested in this event, skip it immediately ... */
33	switch (event) {
34	case FB_EVENT_BLANK:
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:
39		break;
40	default:
41		return 0;
42	}
43
44	ld = container_of(self, struct lcd_device, fb_notif);
45	if (!ld->ops)
46		return 0;
47
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);
61		} else {
62			if (ld->ops->set_mode)
63				ld->ops->set_mode(ld, evdata->data);
64		}
65	}
66	mutex_unlock(&ld->ops_lock);
67	return 0;
68}
69
70static int lcd_register_fb(struct lcd_device *ld)
71{
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);
75}
76
77static void lcd_unregister_fb(struct lcd_device *ld)
78{
79	fb_unregister_client(&ld->fb_notif);
80}
81#else
82static int lcd_register_fb(struct lcd_device *ld)
83{
84	return 0;
85}
86
87static inline void lcd_unregister_fb(struct lcd_device *ld)
88{
89}
90#endif /* CONFIG_FB */
91
92static ssize_t lcd_power_show(struct device *dev, struct device_attribute *attr,
93		char *buf)
94{
95	int rc;
96	struct lcd_device *ld = to_lcd_device(dev);
97
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));
101	else
102		rc = -ENXIO;
103	mutex_unlock(&ld->ops_lock);
104
105	return rc;
106}
107
108static ssize_t lcd_power_store(struct device *dev,
109		struct device_attribute *attr, const char *buf, size_t count)
110{
111	int rc;
112	struct lcd_device *ld = to_lcd_device(dev);
113	unsigned long power;
114
115	rc = kstrtoul(buf, 0, &power);
116	if (rc)
117		return rc;
118
119	rc = -ENXIO;
120
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);
125		rc = count;
126	}
127	mutex_unlock(&ld->ops_lock);
128
129	return rc;
130}
131static DEVICE_ATTR_RW(lcd_power);
132
133static ssize_t contrast_show(struct device *dev,
134		struct device_attribute *attr, char *buf)
135{
136	int rc = -ENXIO;
137	struct lcd_device *ld = to_lcd_device(dev);
138
139	mutex_lock(&ld->ops_lock);
140	if (ld->ops && ld->ops->get_contrast)
141		rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld));
142	mutex_unlock(&ld->ops_lock);
143
144	return rc;
145}
146
147static ssize_t contrast_store(struct device *dev,
148		struct device_attribute *attr, const char *buf, size_t count)
149{
150	int rc;
151	struct lcd_device *ld = to_lcd_device(dev);
152	unsigned long contrast;
153
154	rc = kstrtoul(buf, 0, &contrast);
155	if (rc)
156		return rc;
157
158	rc = -ENXIO;
159
160	mutex_lock(&ld->ops_lock);
161	if (ld->ops && ld->ops->set_contrast) {
162		pr_debug("set contrast to %lu\n", contrast);
163		ld->ops->set_contrast(ld, contrast);
164		rc = count;
165	}
166	mutex_unlock(&ld->ops_lock);
167
168	return rc;
169}
170static DEVICE_ATTR_RW(contrast);
171
172static ssize_t max_contrast_show(struct device *dev,
173		struct device_attribute *attr, char *buf)
174{
175	struct lcd_device *ld = to_lcd_device(dev);
176
177	return sprintf(buf, "%d\n", ld->props.max_contrast);
178}
179static DEVICE_ATTR_RO(max_contrast);
180
181static struct class *lcd_class;
182
183static void lcd_device_release(struct device *dev)
184{
185	struct lcd_device *ld = to_lcd_device(dev);
186	kfree(ld);
187}
188
189static struct attribute *lcd_device_attrs[] = {
190	&dev_attr_lcd_power.attr,
191	&dev_attr_contrast.attr,
192	&dev_attr_max_contrast.attr,
193	NULL,
194};
195ATTRIBUTE_GROUPS(lcd_device);
196
197/**
198 * lcd_device_register - register a new object of lcd_device class.
199 * @name: the name of the new object(must be the same as the name of the
200 *   respective framebuffer device).
201 * @devdata: an optional pointer to be stored in the device. The
202 *   methods may retrieve it by using lcd_get_data(ld).
203 * @ops: the lcd operations structure.
204 *
205 * Creates and registers a new lcd device. Returns either an ERR_PTR()
206 * or a pointer to the newly allocated device.
207 */
208struct lcd_device *lcd_device_register(const char *name, struct device *parent,
209		void *devdata, struct lcd_ops *ops)
210{
211	struct lcd_device *new_ld;
212	int rc;
213
214	pr_debug("lcd_device_register: name=%s\n", name);
215
216	new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL);
217	if (!new_ld)
218		return ERR_PTR(-ENOMEM);
219
220	mutex_init(&new_ld->ops_lock);
221	mutex_init(&new_ld->update_lock);
222
223	new_ld->dev.class = lcd_class;
224	new_ld->dev.parent = parent;
225	new_ld->dev.release = lcd_device_release;
226	dev_set_name(&new_ld->dev, "%s", name);
227	dev_set_drvdata(&new_ld->dev, devdata);
228
229	rc = device_register(&new_ld->dev);
230	if (rc) {
231		put_device(&new_ld->dev);
232		return ERR_PTR(rc);
233	}
234
235	rc = lcd_register_fb(new_ld);
236	if (rc) {
237		device_unregister(&new_ld->dev);
238		return ERR_PTR(rc);
239	}
240
241	new_ld->ops = ops;
242
243	return new_ld;
244}
245EXPORT_SYMBOL(lcd_device_register);
246
247/**
248 * lcd_device_unregister - unregisters a object of lcd_device class.
249 * @ld: the lcd device object to be unregistered and freed.
250 *
251 * Unregisters a previously registered via lcd_device_register object.
252 */
253void lcd_device_unregister(struct lcd_device *ld)
254{
255	if (!ld)
256		return;
257
258	mutex_lock(&ld->ops_lock);
259	ld->ops = NULL;
260	mutex_unlock(&ld->ops_lock);
261	lcd_unregister_fb(ld);
262
263	device_unregister(&ld->dev);
264}
265EXPORT_SYMBOL(lcd_device_unregister);
266
267static void devm_lcd_device_release(struct device *dev, void *res)
268{
269	struct lcd_device *lcd = *(struct lcd_device **)res;
270
271	lcd_device_unregister(lcd);
272}
273
274static int devm_lcd_device_match(struct device *dev, void *res, void *data)
275{
276	struct lcd_device **r = res;
277
278	return *r == data;
279}
280
281/**
282 * devm_lcd_device_register - resource managed lcd_device_register()
283 * @dev: the device to register
284 * @name: the name of the device
285 * @parent: a pointer to the parent device
286 * @devdata: an optional pointer to be stored for private driver use
287 * @ops: the lcd operations structure
288 *
289 * @return a struct lcd on success, or an ERR_PTR on error
290 *
291 * Managed lcd_device_register(). The lcd_device returned from this function
292 * are automatically freed on driver detach. See lcd_device_register()
293 * for more information.
294 */
295struct lcd_device *devm_lcd_device_register(struct device *dev,
296		const char *name, struct device *parent,
297		void *devdata, struct lcd_ops *ops)
298{
299	struct lcd_device **ptr, *lcd;
300
301	ptr = devres_alloc(devm_lcd_device_release, sizeof(*ptr), GFP_KERNEL);
302	if (!ptr)
303		return ERR_PTR(-ENOMEM);
304
305	lcd = lcd_device_register(name, parent, devdata, ops);
306	if (!IS_ERR(lcd)) {
307		*ptr = lcd;
308		devres_add(dev, ptr);
309	} else {
310		devres_free(ptr);
311	}
312
313	return lcd;
314}
315EXPORT_SYMBOL(devm_lcd_device_register);
316
317/**
318 * devm_lcd_device_unregister - resource managed lcd_device_unregister()
319 * @dev: the device to unregister
320 * @ld: the lcd device to unregister
321 *
322 * Deallocated a lcd allocated with devm_lcd_device_register(). Normally
323 * this function will not need to be called and the resource management
324 * code will ensure that the resource is freed.
325 */
326void devm_lcd_device_unregister(struct device *dev, struct lcd_device *ld)
327{
328	int rc;
329
330	rc = devres_release(dev, devm_lcd_device_release,
331				devm_lcd_device_match, ld);
332	WARN_ON(rc);
333}
334EXPORT_SYMBOL(devm_lcd_device_unregister);
335
336
337static void __exit lcd_class_exit(void)
338{
339	class_destroy(lcd_class);
340}
341
342static int __init lcd_class_init(void)
343{
344	lcd_class = class_create(THIS_MODULE, "lcd");
345	if (IS_ERR(lcd_class)) {
346		pr_warn("Unable to create backlight class; errno = %ld\n",
347			PTR_ERR(lcd_class));
348		return PTR_ERR(lcd_class);
349	}
350
351	lcd_class->dev_groups = lcd_device_groups;
352	return 0;
353}
354
355/*
356 * if this is compiled into the kernel, we need to ensure that the
357 * class is registered before users of the class try to register lcd's
358 */
359postcore_initcall(lcd_class_init);
360module_exit(lcd_class_exit);
361
362MODULE_LICENSE("GPL");
363MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
364MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");
365