linux/drivers/video/output.c
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   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
  31MODULE_DESCRIPTION("Display Output Switcher Lowlevel Control Abstraction");
  32MODULE_LICENSE("GPL");
  33MODULE_AUTHOR("Luming Yu <luming.yu@intel.com>");
  34
  35static 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
  45static 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
  66static void video_output_release(struct device *dev)
  67{
  68        struct output_device *od = to_output_device(dev);
  69        kfree(od);
  70}
  71
  72static struct device_attribute video_output_attributes[] = {
  73        __ATTR(state, 0644, video_output_show_state, video_output_store_state),
  74        __ATTR_NULL,
  75};
  76
  77
  78static struct class video_output_class = {
  79        .name = "video_output",
  80        .dev_release = video_output_release,
  81        .dev_attrs = video_output_attributes,
  82};
  83
  84struct 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
 109error_return:
 110        return ERR_PTR(ret_code);
 111}
 112EXPORT_SYMBOL(video_output_register);
 113
 114void video_output_unregister(struct output_device *dev)
 115{
 116        if (!dev)
 117                return;
 118        device_unregister(&dev->dev);
 119}
 120EXPORT_SYMBOL(video_output_unregister);
 121
 122static void __exit video_output_class_exit(void)
 123{
 124        class_unregister(&video_output_class);
 125}
 126
 127static int __init video_output_class_init(void)
 128{
 129        return class_register(&video_output_class);
 130}
 131
 132postcore_initcall(video_output_class_init);
 133module_exit(video_output_class_exit);
 134
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