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 #include <linux/slab.h>
  31
  32 static ssize_t display_show_name(struct device *dev,
  33                                 struct device_attribute *attr, char *buf)
  34 {
  35         struct display_device *dsp = dev_get_drvdata(dev);
  36         return snprintf(buf, PAGE_SIZE, "%s\n", dsp->name);
  37 }
  38
  39 static ssize_t display_show_type(struct device *dev,
  40                                 struct device_attribute *attr, char *buf)
  41 {
  42         struct display_device *dsp = dev_get_drvdata(dev);
  43         return snprintf(buf, PAGE_SIZE, "%s\n", dsp->type);
  44 }
  45
  46 static ssize_t display_show_contrast(struct device *dev,
  47                                 struct device_attribute *attr, char *buf)
  48 {
  49         struct display_device *dsp = dev_get_drvdata(dev);
  50         ssize_t rc = -ENXIO;
  51
  52         mutex_lock(&dsp->lock);
  53         if (likely(dsp->driver) && dsp->driver->get_contrast)
  54                 rc = sprintf(buf, "%d\n", dsp->driver->get_contrast(dsp));
  55         mutex_unlock(&dsp->lock);
  56         return rc;
  57 }
  58
  59 static ssize_t display_store_contrast(struct device *dev,
  60                                         struct device_attribute *attr,
  61                                         const char *buf, size_t count)
  62 {
  63         struct display_device *dsp = dev_get_drvdata(dev);
  64         ssize_t ret = -EINVAL, size;
  65         int contrast;
  66         char *endp;
  67
  68         contrast = simple_strtoul(buf, &endp, 0);
  69         size = endp - buf;
  70
  71         if (isspace(*endp))
  72                 size++;
  73
  74         if (size != count)
  75                 return ret;
  76
  77         mutex_lock(&dsp->lock);
  78         if (likely(dsp->driver && dsp->driver->set_contrast)) {
  79                 pr_debug("display: set contrast to %d\n", contrast);
  80                 dsp->driver->set_contrast(dsp, contrast);
  81                 ret = count;
  82         }
  83         mutex_unlock(&dsp->lock);
  84         return ret;
  85 }
  86
  87 static ssize_t display_show_max_contrast(struct device *dev,
  88                                         struct device_attribute *attr,
  89                                         char *buf)
  90 {
  91         struct display_device *dsp = dev_get_drvdata(dev);
  92         ssize_t rc = -ENXIO;
  93
  94         mutex_lock(&dsp->lock);
  95         if (likely(dsp->driver))
  96                 rc = sprintf(buf, "%d\n", dsp->driver->max_contrast);
  97         mutex_unlock(&dsp->lock);
  98         return rc;
  99 }
 100
 101 static struct device_attribute display_attrs[] = {
 102         __ATTR(name, S_IRUGO, display_show_name, NULL),
 103         __ATTR(type, S_IRUGO, display_show_type, NULL),
 104         __ATTR(contrast, S_IRUGO | S_IWUSR, display_show_contrast, display_store_contrast),
 105         __ATTR(max_contrast, S_IRUGO, display_show_max_contrast, NULL),
 106 };
 107
 108 static int display_suspend(struct device *dev, pm_message_t state)
 109 {
 110         struct display_device *dsp = dev_get_drvdata(dev);
 111
 112         mutex_lock(&dsp->lock);
 113         if (likely(dsp->driver->suspend))
 114                 dsp->driver->suspend(dsp, state);
 115         mutex_unlock(&dsp->lock);
 116         return 0;
 117 };
 118
 119 static int display_resume(struct device *dev)
 120 {
 121         struct display_device *dsp = dev_get_drvdata(dev);
 122
 123         mutex_lock(&dsp->lock);
 124         if (likely(dsp->driver->resume))
 125                 dsp->driver->resume(dsp);
 126         mutex_unlock(&dsp->lock);
 127         return 0;
 128 };
 129
 130 static struct mutex allocated_dsp_lock;
 131 static DEFINE_IDR(allocated_dsp);
 132 static struct class *display_class;
 133
 134 struct display_device *display_device_register(struct display_driver *driver,
 135                                                 struct device *parent, void *devdata)
 136 {
 137         struct display_device *new_dev = NULL;
 138         int ret = -EINVAL;
 139
 140         if (unlikely(!driver))
 141                 return ERR_PTR(ret);
 142
 143         mutex_lock(&allocated_dsp_lock);
 144         ret = idr_pre_get(&allocated_dsp, GFP_KERNEL);
 145         mutex_unlock(&allocated_dsp_lock);
 146         if (!ret)
 147                 return ERR_PTR(ret);
 148
 149         new_dev = kzalloc(sizeof(struct display_device), GFP_KERNEL);
 150         if (likely(new_dev) && unlikely(driver->probe(new_dev, devdata))) {
 151                 // Reserve the index for this display
 152                 mutex_lock(&allocated_dsp_lock);
 153                 ret = idr_get_new(&allocated_dsp, new_dev, &new_dev->idx);
 154                 mutex_unlock(&allocated_dsp_lock);
 155
 156                 if (!ret) {
 157                         new_dev->dev = device_create(display_class, parent,
 158                                                      MKDEV(0, 0), new_dev,
 159                                                      "display%d", new_dev->idx);
 160                         if (!IS_ERR(new_dev->dev)) {
 161                                 new_dev->parent = parent;
 162                                 new_dev->driver = driver;
 163                                 mutex_init(&new_dev->lock);
 164                                 return new_dev;
 165                         }
 166                         mutex_lock(&allocated_dsp_lock);
 167                         idr_remove(&allocated_dsp, new_dev->idx);
 168                         mutex_unlock(&allocated_dsp_lock);
 169                         ret = -EINVAL;
 170                 }
 171         }
 172         kfree(new_dev);
 173         return ERR_PTR(ret);
 174 }
 175 EXPORT_SYMBOL(display_device_register);
 176
 177 void display_device_unregister(struct display_device *ddev)
 178 {
 179         if (!ddev)
 180                 return;
 181         // Free device
 182         mutex_lock(&ddev->lock);
 183         device_unregister(ddev->dev);
 184         mutex_unlock(&ddev->lock);
 185         // Mark device index as available
 186         mutex_lock(&allocated_dsp_lock);
 187         idr_remove(&allocated_dsp, ddev->idx);
 188         mutex_unlock(&allocated_dsp_lock);
 189         kfree(ddev);
 190 }
 191 EXPORT_SYMBOL(display_device_unregister);
 192
 193 static int __init display_class_init(void)
 194 {
 195         display_class = class_create(THIS_MODULE, "display");
 196         if (IS_ERR(display_class)) {
 197                 printk(KERN_ERR "Failed to create display class\n");
 198                 display_class = NULL;
 199                 return -EINVAL;
 200         }
 201         display_class->dev_attrs = display_attrs;
 202         display_class->suspend = display_suspend;
 203         display_class->resume = display_resume;
 204         mutex_init(&allocated_dsp_lock);
 205         return 0;
 206 }
 207
 208 static void __exit display_class_exit(void)
 209 {
 210         class_destroy(display_class);
 211 }
 212
 213 module_init(display_class_init);
 214 module_exit(display_class_exit);
 215
 216 MODULE_DESCRIPTION("Display Hardware handling");
 217 MODULE_AUTHOR("James Simmons <jsimmons@infradead.org>");
 218 MODULE_LICENSE("GPL");
 219