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 class_device *dev,char *buf)
  35 {
  36         ssize_t ret_size = 0;
  37         struct output_device *od = to_output_device(dev);
  38         if (od->props)
  39                 ret_size = sprintf(buf,"%.8x\n",od->props->get_status(od));
  40         return ret_size;
  41 }
  42
  43 static ssize_t video_output_store_state(struct class_device *dev,
  44         const char *buf,size_t count)
  45 {
  46         char *endp;
  47         struct output_device *od = to_output_device(dev);
  48         int request_state = simple_strtoul(buf,&endp,0);
  49         size_t size = endp - buf;
  50
  51         if (*endp && isspace(*endp))
  52                 size++;
  53         if (size != count)
  54                 return -EINVAL;
  55
  56         if (od->props) {
  57                 od->request_state = request_state;
  58                 od->props->set_state(od);
  59         }
  60         return count;
  61 }
  62
  63 static void video_output_class_release(struct class_device *dev)
  64 {
  65         struct output_device *od = to_output_device(dev);
  66         kfree(od);
  67 }
  68
  69 static struct class_device_attribute video_output_attributes[] = {
  70         __ATTR(state, 0644, video_output_show_state, video_output_store_state),
  71         __ATTR_NULL,
  72 };
  73
  74 static struct class video_output_class = {
  75         .name = "video_output",
  76         .release = video_output_class_release,
  77         .class_dev_attrs = video_output_attributes,
  78 };
  79
  80 struct output_device *video_output_register(const char *name,
  81         struct device *dev,
  82         void *devdata,
  83         struct output_properties *op)
  84 {
  85         struct output_device *new_dev;
  86         int ret_code = 0;
  87
  88         new_dev = kzalloc(sizeof(struct output_device),GFP_KERNEL);
  89         if (!new_dev) {
  90                 ret_code = -ENOMEM;
  91                 goto error_return;
  92         }
  93         new_dev->props = op;
  94         new_dev->class_dev.class = &video_output_class;
  95         new_dev->class_dev.dev = dev;
  96         strlcpy(new_dev->class_dev.class_id,name,KOBJ_NAME_LEN);
  97         class_set_devdata(&new_dev->class_dev,devdata);
  98         ret_code = class_device_register(&new_dev->class_dev);
  99         if (ret_code) {
 100                 kfree(new_dev);
 101                 goto error_return;
 102         }
 103         return new_dev;
 104
 105 error_return:
 106         return ERR_PTR(ret_code);
 107 }
 108 EXPORT_SYMBOL(video_output_register);
 109
 110 void video_output_unregister(struct output_device *dev)
 111 {
 112         if (!dev)
 113                 return;
 114         class_device_unregister(&dev->class_dev);
 115 }
 116 EXPORT_SYMBOL(video_output_unregister);
 117
 118 static void __exit video_output_class_exit(void)
 119 {
 120         class_unregister(&video_output_class);
 121 }
 122
 123 static int __init video_output_class_init(void)
 124 {
 125         return class_register(&video_output_class);
 126 }
 127
 128 postcore_initcall(video_output_class_init);
 129 module_exit(video_output_class_exit);