tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * display-sysfs.c - Display output driver sysfs interface
3 *
4 * Copyright (C) 2007 James Simmons <jsimmons@infradead.org>
5 *
6 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or (at
11 * your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License along
19 * with this program; if not, write to the Free Software Foundation, Inc.,
20 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
21 *
22 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
23 */
24#include <linux/module.h>
25#include <linux/display.h>
26#include <linux/ctype.h>
27#include <linux/idr.h>
28#include <linux/err.h>
29#include <linux/kdev_t.h>
30
31static ssize_t display_show_name(struct device *dev,
32 struct device_attribute *attr, char *buf)
33{
34 struct display_device *dsp = dev_get_drvdata(dev);
35 return snprintf(buf, PAGE_SIZE, "%s\n", dsp->name);
36}
37
38static ssize_t display_show_type(struct device *dev,
39 struct device_attribute *attr, char *buf)
40{
41 struct display_device *dsp = dev_get_drvdata(dev);
42 return snprintf(buf, PAGE_SIZE, "%s\n", dsp->type);
43}
44
45static ssize_t display_show_contrast(struct device *dev,
46 struct device_attribute *attr, char *buf)
47{
48 struct display_device *dsp = dev_get_drvdata(dev);
49 ssize_t rc = -ENXIO;
50
51 mutex_lock(&dsp->lock);
52 if (likely(dsp->driver) && dsp->driver->get_contrast)
53 rc = sprintf(buf, "%d\n", dsp->driver->get_contrast(dsp));
54 mutex_unlock(&dsp->lock);
55 return rc;
56}
57
58static ssize_t display_store_contrast(struct device *dev,
59 struct device_attribute *attr,
60 const char *buf, size_t count)
61{
62 struct display_device *dsp = dev_get_drvdata(dev);
63 ssize_t ret = -EINVAL, size;
64 int contrast;
65 char *endp;
66
67 contrast = simple_strtoul(buf, &endp, 0);
68 size = endp - buf;
69
70 if (*endp && isspace(*endp))
71 size++;
72
73 if (size != count)
74 return ret;
75
76 mutex_lock(&dsp->lock);
77 if (likely(dsp->driver && dsp->driver->set_contrast)) {
78 pr_debug("display: set contrast to %d\n", contrast);
79 dsp->driver->set_contrast(dsp, contrast);
80 ret = count;
81 }
82 mutex_unlock(&dsp->lock);
83 return ret;
84}
85
86static ssize_t display_show_max_contrast(struct device *dev,
87 struct device_attribute *attr,
88 char *buf)
89{
90 struct display_device *dsp = dev_get_drvdata(dev);
91 ssize_t rc = -ENXIO;
92
93 mutex_lock(&dsp->lock);
94 if (likely(dsp->driver))
95 rc = sprintf(buf, "%d\n", dsp->driver->max_contrast);
96 mutex_unlock(&dsp->lock);
97 return rc;
98}
99
100static struct device_attribute display_attrs[] = {
101 __ATTR(name, S_IRUGO, display_show_name, NULL),
102 __ATTR(type, S_IRUGO, display_show_type, NULL),
103 __ATTR(contrast, S_IRUGO | S_IWUSR, display_show_contrast, display_store_contrast),
104 __ATTR(max_contrast, S_IRUGO, display_show_max_contrast, NULL),
105};
106
107static int display_suspend(struct device *dev, pm_message_t state)
108{
109 struct display_device *dsp = dev_get_drvdata(dev);
110
111 mutex_lock(&dsp->lock);
112 if (likely(dsp->driver->suspend))
113 dsp->driver->suspend(dsp, state);
114 mutex_unlock(&dsp->lock);
115 return 0;
116};
117
118static int display_resume(struct device *dev)
119{
120 struct display_device *dsp = dev_get_drvdata(dev);
121
122 mutex_lock(&dsp->lock);
123 if (likely(dsp->driver->resume))
124 dsp->driver->resume(dsp);
125 mutex_unlock(&dsp->lock);
126 return 0;
127};
128
129static struct mutex allocated_dsp_lock;
130static DEFINE_IDR(allocated_dsp);
131static struct class *display_class;
132
133struct display_device *display_device_register(struct display_driver *driver,
134 struct device *parent, void *devdata)
135{
136 struct display_device *new_dev = NULL;
137 int ret = -EINVAL;
138
139 if (unlikely(!driver))
140 return ERR_PTR(ret);
141
142 mutex_lock(&allocated_dsp_lock);
143 ret = idr_pre_get(&allocated_dsp, GFP_KERNEL);
144 mutex_unlock(&allocated_dsp_lock);
145 if (!ret)
146 return ERR_PTR(ret);
147
148 new_dev = kzalloc(sizeof(struct display_device), GFP_KERNEL);
149 if (likely(new_dev) && unlikely(driver->probe(new_dev, devdata))) {
150 // Reserve the index for this display
151 mutex_lock(&allocated_dsp_lock);
152 ret = idr_get_new(&allocated_dsp, new_dev, &new_dev->idx);
153 mutex_unlock(&allocated_dsp_lock);
154
155 if (!ret) {
156 new_dev->dev = device_create(display_class, parent,
157 MKDEV(0, 0), new_dev,
158 "display%d", new_dev->idx);
159 if (!IS_ERR(new_dev->dev)) {
160 new_dev->parent = parent;
161 new_dev->driver = driver;
162 mutex_init(&new_dev->lock);
163 return new_dev;
164 }
165 mutex_lock(&allocated_dsp_lock);
166 idr_remove(&allocated_dsp, new_dev->idx);
167 mutex_unlock(&allocated_dsp_lock);
168 ret = -EINVAL;
169 }
170 }
171 kfree(new_dev);
172 return ERR_PTR(ret);
173}
174EXPORT_SYMBOL(display_device_register);
175
176void display_device_unregister(struct display_device *ddev)
177{
178 if (!ddev)
179 return;
180 // Free device
181 mutex_lock(&ddev->lock);
182 device_unregister(ddev->dev);
183 mutex_unlock(&ddev->lock);
184 // Mark device index as avaliable
185 mutex_lock(&allocated_dsp_lock);
186 idr_remove(&allocated_dsp, ddev->idx);
187 mutex_unlock(&allocated_dsp_lock);
188 kfree(ddev);
189}
190EXPORT_SYMBOL(display_device_unregister);
191
192static int __init display_class_init(void)
193{
194 display_class = class_create(THIS_MODULE, "display");
195 if (IS_ERR(display_class)) {
196 printk(KERN_ERR "Failed to create display class\n");
197 display_class = NULL;
198 return -EINVAL;
199 }
200 display_class->dev_attrs = display_attrs;
201 display_class->suspend = display_suspend;
202 display_class->resume = display_resume;
203 mutex_init(&allocated_dsp_lock);
204 return 0;
205}
206
207static void __exit display_class_exit(void)
208{
209 class_destroy(display_class);
210}
211
212module_init(display_class_init);
213module_exit(display_class_exit);
214
215MODULE_DESCRIPTION("Display Hardware handling");
216MODULE_AUTHOR("James Simmons <jsimmons@infradead.org>");
217MODULE_LICENSE("GPL");
218