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