aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/video/backlight/lcd.c
blob: 8e1731d3b2283e311bcad1d6f10475901467cda2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
/*
 * LCD Lowlevel Control Abstraction
 *
 * Copyright (C) 2003,2004 Hewlett-Packard Company
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/lcd.h>
#include <linux/notifier.h>
#include <linux/ctype.h>
#include <linux/err.h>
#include <linux/fb.h>

#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
			   defined(CONFIG_LCD_CLASS_DEVICE_MODULE))
/* This callback gets called when something important happens inside a
 * framebuffer driver. We're looking if that important event is blanking,
 * and if it is, we're switching lcd power as well ...
 */
static int fb_notifier_callback(struct notifier_block *self,
				 unsigned long event, void *data)
{
	struct lcd_device *ld;
	struct fb_event *evdata = data;

	/* If we aren't interested in this event, skip it immediately ... */
	switch (event) {
	case FB_EVENT_BLANK:
	case FB_EVENT_MODE_CHANGE:
	case FB_EVENT_MODE_CHANGE_ALL:
		break;
	default:
		return 0;
	}

	ld = container_of(self, struct lcd_device, fb_notif);
	if (!ld->ops)
		return 0;

	mutex_lock(&ld->ops_lock);
	if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) {
		if (event == FB_EVENT_BLANK)
			ld->ops->set_power(ld, *(int *)evdata->data);
		else
			ld->ops->set_mode(ld, evdata->data);
	}
	mutex_unlock(&ld->ops_lock);
	return 0;
}

static int lcd_register_fb(struct lcd_device *ld)
{
	memset(&ld->fb_notif, 0, sizeof(&ld->fb_notif));
	ld->fb_notif.notifier_call = fb_notifier_callback;
	return fb_register_client(&ld->fb_notif);
}

static void lcd_unregister_fb(struct lcd_device *ld)
{
	fb_unregister_client(&ld->fb_notif);
}
#else
static int lcd_register_fb(struct lcd_device *ld)
{
	return 0;
}

static inline void lcd_unregister_fb(struct lcd_device *ld)
{
}
#endif /* CONFIG_FB */

static ssize_t lcd_show_power(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	int rc;
	struct lcd_device *ld = to_lcd_device(dev);

	mutex_lock(&ld->ops_lock);
	if (ld->ops && ld->ops->get_power)
		rc = sprintf(buf, "%d\n", ld->ops->get_power(ld));
	else
		rc = -ENXIO;
	mutex_unlock(&ld->ops_lock);

	return rc;
}

static ssize_t lcd_store_power(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	int rc = -ENXIO;
	char *endp;
	struct lcd_device *ld = to_lcd_device(dev);
	int power = simple_strtoul(buf, &endp, 0);
	size_t size = endp - buf;

	if (*endp && isspace(*endp))
		size++;
	if (size != count)
		return -EINVAL;

	mutex_lock(&ld->ops_lock);
	if (ld->ops && ld->ops->set_power) {
		pr_debug("lcd: set power to %d\n", power);
		ld->ops->set_power(ld, power);
		rc = count;
	}
	mutex_unlock(&ld->ops_lock);

	return rc;
}

static ssize_t lcd_show_contrast(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	int rc = -ENXIO;
	struct lcd_device *ld = to_lcd_device(dev);

	mutex_lock(&ld->ops_lock);
	if (ld->ops && ld->ops->get_contrast)
		rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld));
	mutex_unlock(&ld->ops_lock);

	return rc;
}

static ssize_t lcd_store_contrast(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	int rc = -ENXIO;
	char *endp;
	struct lcd_device *ld = to_lcd_device(dev);
	int contrast = simple_strtoul(buf, &endp, 0);
	size_t size = endp - buf;

	if (*endp && isspace(*endp))
		size++;
	if (size != count)
		return -EINVAL;

	mutex_lock(&ld->ops_lock);
	if (ld->ops && ld->ops->set_contrast) {
		pr_debug("lcd: set contrast to %d\n", contrast);
		ld->ops->set_contrast(ld, contrast);
		rc = count;
	}
	mutex_unlock(&ld->ops_lock);

	return rc;
}

static ssize_t lcd_show_max_contrast(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct lcd_device *ld = to_lcd_device(dev);

	return sprintf(buf, "%d\n", ld->props.max_contrast);
}

static struct class *lcd_class;

static void lcd_device_release(struct device *dev)
{
	struct lcd_device *ld = to_lcd_device(dev);
	kfree(ld);
}

static struct device_attribute lcd_device_attributes[] = {
	__ATTR(lcd_power, 0644, lcd_show_power, lcd_store_power),
	__ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast),
	__ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL),
	__ATTR_NULL,
};

/**
 * lcd_device_register - register a new object of lcd_device class.
 * @name: the name of the new object(must be the same as the name of the
 *   respective framebuffer device).
 * @devdata: an optional pointer to be stored in the device. The
 *   methods may retrieve it by using lcd_get_data(ld).
 * @ops: the lcd operations structure.
 *
 * Creates and registers a new lcd device. Returns either an ERR_PTR()
 * or a pointer to the newly allocated device.
 */
struct lcd_device *lcd_device_register(const char *name, struct device *parent,
		void *devdata, struct lcd_ops *ops)
{
	struct lcd_device *new_ld;
	int rc;

	pr_debug("lcd_device_register: name=%s\n", name);

	new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL);
	if (!new_ld)
		return ERR_PTR(-ENOMEM);

	mutex_init(&new_ld->ops_lock);
	mutex_init(&new_ld->update_lock);

	new_ld->dev.class = lcd_class;
	new_ld->dev.parent = parent;
	new_ld->dev.release = lcd_device_release;
	strlcpy(new_ld->dev.bus_id, name, BUS_ID_SIZE);
	dev_set_drvdata(&new_ld->dev, devdata);

	rc = device_register(&new_ld->dev);
	if (rc) {
		kfree(new_ld);
		return ERR_PTR(rc);
	}

	rc = lcd_register_fb(new_ld);
	if (rc) {
		device_unregister(&new_ld->dev);
		return ERR_PTR(rc);
	}

	new_ld->ops = ops;

	return new_ld;
}
EXPORT_SYMBOL(lcd_device_register);

/**
 * lcd_device_unregister - unregisters a object of lcd_device class.
 * @ld: the lcd device object to be unregistered and freed.
 *
 * Unregisters a previously registered via lcd_device_register object.
 */
void lcd_device_unregister(struct lcd_device *ld)
{
	if (!ld)
		return;

	mutex_lock(&ld->ops_lock);
	ld->ops = NULL;
	mutex_unlock(&ld->ops_lock);
	lcd_unregister_fb(ld);

	device_unregister(&ld->dev);
}
EXPORT_SYMBOL(lcd_device_unregister);

static void __exit lcd_class_exit(void)
{
	class_destroy(lcd_class);
}

static int __init lcd_class_init(void)
{
	lcd_class = class_create(THIS_MODULE, "lcd");
	if (IS_ERR(lcd_class)) {
		printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",
				PTR_ERR(lcd_class));
		return PTR_ERR(lcd_class);
	}

	lcd_class->dev_attrs = lcd_device_attributes;
	return 0;
}

/*
 * if this is compiled into the kernel, we need to ensure that the
 * class is registered before users of the class try to register lcd's
 */
postcore_initcall(lcd_class_init);
module_exit(lcd_class_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");