drivers/video/output.c

   1 /*
   2  *  output.c - Display Output Switch driver
   3  *
   4  *  Copyright (C) 2006 Luming Yu <luming.yu@intel.com>
   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/video_output.h>
  26 #include <linux/err.h>
  27 #include <linux/ctype.h>
  28
  29
  30 MODULE_DESCRIPTION("Display Output Switcher Lowlevel Control Abstraction");
  31 MODULE_LICENSE("GPL");
  32 MODULE_AUTHOR("Luming Yu <luming.yu@intel.com>");
  33
  34 static ssize_t video_output_show_state(struct device *dev,
  35                                        struct device_attribute *attr, char *buf)
  36 {
  37         ssize_t ret_size = 0;
  38         struct output_device *od = to_output_device(dev);
  39         if (od->props)
  40                 ret_size = sprintf(buf,"%.8x\n",od->props->get_status(od));
  41         return ret_size;
  42 }
  43
  44 static ssize_t video_output_store_state(struct device *dev,
  45                                         struct device_attribute *attr,
  46                                         const char *buf,size_t count)
  47 {
  48         char *endp;
  49         struct output_device *od = to_output_device(dev);
  50         int request_state = simple_strtoul(buf,&endp,0);
  51         size_t size = endp - buf;
  52
  53         if (isspace(*endp))
  54                 size++;
  55         if (size != count)
  56                 return -EINVAL;
  57
  58         if (od->props) {
  59                 od->request_state = request_state;
  60                 od->props->set_state(od);
  61         }
  62         return count;
  63 }
  64
  65 static void video_output_release(struct device *dev)
  66 {
  67         struct output_device *od = to_output_device(dev);
  68         kfree(od);
  69 }
  70
  71 static struct device_attribute video_output_attributes[] = {
  72         __ATTR(state, 0644, video_output_show_state, video_output_store_state),
  73         __ATTR_NULL,
  74 };
  75
  76
  77 static struct class video_output_class = {
  78         .name = "video_output",
  79         .dev_release = video_output_release,
  80         .dev_attrs = video_output_attributes,
  81 };
  82
  83 struct output_device *video_output_register(const char *name,
  84         struct device *dev,
  85         void *devdata,
  86         struct output_properties *op)
  87 {
  88         struct output_device *new_dev;
  89         int ret_code = 0;
  90
  91         new_dev = kzalloc(sizeof(struct output_device),GFP_KERNEL);
  92         if (!new_dev) {
  93                 ret_code = -ENOMEM;
  94                 goto error_return;
  95         }
  96         new_dev->props = op;
  97         new_dev->dev.class = &video_output_class;
  98         new_dev->dev.parent = dev;
  99         dev_set_name(&new_dev->dev, name);
 100         dev_set_drvdata(&new_dev->dev, devdata);
 101         ret_code = device_register(&new_dev->dev);
 102         if (ret_code) {
 103                 kfree(new_dev);
 104                 goto error_return;
 105         }
 106         return new_dev;
 107
 108 error_return:
 109         return ERR_PTR(ret_code);
 110 }
 111 EXPORT_SYMBOL(video_output_register);
 112
 113 void video_output_unregister(struct output_device *dev)
 114 {
 115         if (!dev)
 116                 return;
 117         device_unregister(&dev->dev);
 118 }
 119 EXPORT_SYMBOL(video_output_unregister);
 120
 121 static void __exit video_output_class_exit(void)
 122 {
 123         class_unregister(&video_output_class);
 124 }
 125
 126 static int __init video_output_class_init(void)
 127 {
 128         return class_register(&video_output_class);
 129 }
 130
 131 postcore_initcall(video_output_class_init);
 132 module_exit(video_output_class_exit);