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
  30 static ssize_t display_show_name(struct device *dev,
  31                                 struct device_attribute *attr, char *buf)
  32 {
  33         struct display_device *dsp = dev_get_drvdata(dev);
  34         return snprintf(buf, PAGE_SIZE, "%s\n", dsp->name);
  35 }
  36
  37 static ssize_t display_show_type(struct device *dev,
  38                                 struct device_attribute *attr, char *buf)
  39 {
  40         struct display_device *dsp = dev_get_drvdata(dev);
  41         return snprintf(buf, PAGE_SIZE, "%s\n", dsp->type);
  42 }
  43
  44 static ssize_t display_show_contrast(struct device *dev,
  45                                 struct device_attribute *attr, char *buf)
  46 {
  47         struct display_device *dsp = dev_get_drvdata(dev);
  48         ssize_t rc = -ENXIO;
  49
  50         mutex_lock(&dsp->lock);
  51         if (likely(dsp->driver) && dsp->driver->get_contrast)
  52                 rc = sprintf(buf, "%d\n", dsp->driver->get_contrast(dsp));
  53         mutex_unlock(&dsp->lock);
  54         return rc;
  55 }
  56
  57 static ssize_t display_store_contrast(struct device *dev,
  58                                         struct device_attribute *attr,
  59                                         const char *buf, size_t count)
  60 {
  61         struct display_device *dsp = dev_get_drvdata(dev);
  62         ssize_t ret = -EINVAL, size;
  63         int contrast;
  64         char *endp;
  65
  66         contrast = simple_strtoul(buf, &endp, 0);
  67         size = endp - buf;
  68
  69         if (*endp && isspace(*endp))
  70                 size++;
  71
  72         if (size != count)
  73                 return ret;
  74
  75         mutex_lock(&dsp->lock);
  76         if (likely(dsp->driver && dsp->driver->set_contrast)) {
  77                 pr_debug("display: set contrast to %d\n", contrast);
  78                 dsp->driver->set_contrast(dsp, contrast);
  79                 ret = count;
  80         }
  81         mutex_unlock(&dsp->lock);
  82         return ret;
  83 }
  84
  85 static ssize_t display_show_max_contrast(struct device *dev,
  86                                         struct device_attribute *attr,
  87                                         char *buf)
  88 {
  89         struct display_device *dsp = dev_get_drvdata(dev);
  90         ssize_t rc = -ENXIO;
  91
  92         mutex_lock(&dsp->lock);
  93         if (likely(dsp->driver))
  94                 rc = sprintf(buf, "%d\n", dsp->driver->max_contrast);
  95         mutex_unlock(&dsp->lock);
  96         return rc;
  97 }
  98
  99 static struct device_attribute display_attrs[] = {
 100         __ATTR(name, S_IRUGO, display_show_name, NULL),
 101         __ATTR(type, S_IRUGO, display_show_type, NULL),
 102         __ATTR(contrast, S_IRUGO | S_IWUSR, display_show_contrast, display_store_contrast),
 103         __ATTR(max_contrast, S_IRUGO, display_show_max_contrast, NULL),
 104 };
 105
 106 static int display_suspend(struct device *dev, pm_message_t state)
 107 {
 108         struct display_device *dsp = dev_get_drvdata(dev);
 109
 110         mutex_lock(&dsp->lock);
 111         if (likely(dsp->driver->suspend))
 112                 dsp->driver->suspend(dsp, state);
 113         mutex_unlock(&dsp->lock);
 114         return 0;
 115 };
 116
 117 static int display_resume(struct device *dev)
 118 {
 119         struct display_device *dsp = dev_get_drvdata(dev);
 120
 121         mutex_lock(&dsp->lock);
 122         if (likely(dsp->driver->resume))
 123                 dsp->driver->resume(dsp);
 124         mutex_unlock(&dsp->lock);
 125         return 0;
 126 };
 127
 128 static struct mutex allocated_dsp_lock;
 129 static DEFINE_IDR(allocated_dsp);
 130 static struct class *display_class;
 131
 132 struct display_device *display_device_register(struct display_driver *driver,
 133                                                 struct device *parent, void *devdata)
 134 {
 135         struct display_device *new_dev = NULL;
 136         int ret = -EINVAL;
 137
 138         if (unlikely(!driver))
 139                 return ERR_PTR(ret);
 140
 141         mutex_lock(&allocated_dsp_lock);
 142         ret = idr_pre_get(&allocated_dsp, GFP_KERNEL);
 143         mutex_unlock(&allocated_dsp_lock);
 144         if (!ret)
 145                 return ERR_PTR(ret);
 146
 147         new_dev = kzalloc(sizeof(struct display_device), GFP_KERNEL);
 148         if (likely(new_dev) && unlikely(driver->probe(new_dev, devdata))) {
 149                 // Reserve the index for this display
 150                 mutex_lock(&allocated_dsp_lock);
 151                 ret = idr_get_new(&allocated_dsp, new_dev, &new_dev->idx);
 152                 mutex_unlock(&allocated_dsp_lock);
 153
 154                 if (!ret) {
 155                         new_dev->dev = device_create(display_class, parent, 0,
 156                                                 "display%d", new_dev->idx);
 157                         if (!IS_ERR(new_dev->dev)) {
 158                                 dev_set_drvdata(new_dev->dev, new_dev);
 159                                 new_dev->parent = parent;
 160                                 new_dev->driver = driver;
 161                                 mutex_init(&new_dev->lock);
 162                                 return new_dev;
 163                         }
 164                         mutex_lock(&allocated_dsp_lock);
 165                         idr_remove(&allocated_dsp, new_dev->idx);
 166                         mutex_unlock(&allocated_dsp_lock);
 167                         ret = -EINVAL;
 168                 }
 169         }
 170         kfree(new_dev);
 171         return ERR_PTR(ret);
 172 }
 173 EXPORT_SYMBOL(display_device_register);
 174
 175 void display_device_unregister(struct display_device *ddev)
 176 {
 177         if (!ddev)
 178                 return;
 179         // Free device
 180         mutex_lock(&ddev->lock);
 181         device_unregister(ddev->dev);
 182         mutex_unlock(&ddev->lock);
 183         // Mark device index as avaliable
 184         mutex_lock(&allocated_dsp_lock);
 185         idr_remove(&allocated_dsp, ddev->idx);
 186         mutex_unlock(&allocated_dsp_lock);
 187         kfree(ddev);
 188 }
 189 EXPORT_SYMBOL(display_device_unregister);
 190
 191 static int __init display_class_init(void)
 192 {
 193         display_class = class_create(THIS_MODULE, "display");
 194         if (IS_ERR(display_class)) {
 195                 printk(KERN_ERR "Failed to create display class\n");
 196                 display_class = NULL;
 197                 return -EINVAL;
 198         }
 199         display_class->dev_attrs = display_attrs;
 200         display_class->suspend = display_suspend;
 201         display_class->resume = display_resume;
 202         mutex_init(&allocated_dsp_lock);
 203         return 0;
 204 }
 205
 206 static void __exit display_class_exit(void)
 207 {
 208         class_destroy(display_class);
 209 }
 210
 211 module_init(display_class_init);
 212 module_exit(display_class_exit);
 213
 214 MODULE_DESCRIPTION("Display Hardware handling");
 215 MODULE_AUTHOR("James Simmons <jsimmons@infradead.org>");
 216 MODULE_LICENSE("GPL");
 217