drivers/video/display/display-sysfs.c

   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
  31 static 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
  38 static 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
  45 static 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
  58 static 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
  86 static 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
 100 static 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
 107 static 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
 118 static 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
 129 static struct mutex allocated_dsp_lock;
 130 static DEFINE_IDR(allocated_dsp);
 131 static struct class *display_class;
 132
 133 struct 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 }
 174 EXPORT_SYMBOL(display_device_register);
 175
 176 void 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 }
 190 EXPORT_SYMBOL(display_device_unregister);
 191
 192 static 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
 207 static void __exit display_class_exit(void)
 208 {
 209         class_destroy(display_class);
 210 }
 211
 212 module_init(display_class_init);
 213 module_exit(display_class_exit);
 214
 215 MODULE_DESCRIPTION("Display Hardware handling");
 216 MODULE_AUTHOR("James Simmons <jsimmons@infradead.org>");
 217 MODULE_LICENSE("GPL");
 218