drivers/video/fbdev/via/via_aux_edid.c

   1 /*
   2  * Copyright 2011 Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License as published by the Free Software Foundation;
   7  * either version 2, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTIES OR REPRESENTATIONS; without even
  11  * the implied warranty of MERCHANTABILITY or FITNESS FOR
  12  * A PARTICULAR PURPOSE.See the GNU General Public License
  13  * for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc.,
  18  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20 /*
  21  * generic EDID driver
  22  */
  23
  24 #include <linux/slab.h>
  25 #include <linux/fb.h>
  26 #include "via_aux.h"
  27 #include "../edid.h"
  28
  29
  30 static const char *name = "EDID";
  31
  32
  33 static void query_edid(struct via_aux_drv *drv)
  34 {
  35         struct fb_monspecs *spec = drv->data;
  36         unsigned char edid[EDID_LENGTH];
  37         bool valid = false;
  38
  39         if (spec) {
  40                 fb_destroy_modedb(spec->modedb);
  41         } else {
  42                 spec = kmalloc(sizeof(*spec), GFP_KERNEL);
  43                 if (!spec)
  44                         return;
  45         }
  46
  47         spec->version = spec->revision = 0;
  48         if (via_aux_read(drv, 0x00, edid, EDID_LENGTH)) {
  49                 fb_edid_to_monspecs(edid, spec);
  50                 valid = spec->version || spec->revision;
  51         }
  52
  53         if (!valid) {
  54                 kfree(spec);
  55                 spec = NULL;
  56         } else
  57                 printk(KERN_DEBUG "EDID: %s %s\n", spec->manufacturer, spec->monitor);
  58
  59         drv->data = spec;
  60 }
  61
  62 static const struct fb_videomode *get_preferred_mode(struct via_aux_drv *drv)
  63 {
  64         struct fb_monspecs *spec = drv->data;
  65         int i;
  66
  67         if (!spec || !spec->modedb || !(spec->misc & FB_MISC_1ST_DETAIL))
  68                 return NULL;
  69
  70         for (i = 0; i < spec->modedb_len; i++) {
  71                 if (spec->modedb[i].flag & FB_MODE_IS_FIRST &&
  72                         spec->modedb[i].flag & FB_MODE_IS_DETAILED)
  73                         return &spec->modedb[i];
  74         }
  75
  76         return NULL;
  77 }
  78
  79 static void cleanup(struct via_aux_drv *drv)
  80 {
  81         struct fb_monspecs *spec = drv->data;
  82
  83         if (spec)
  84                 fb_destroy_modedb(spec->modedb);
  85 }
  86
  87 void via_aux_edid_probe(struct via_aux_bus *bus)
  88 {
  89         struct via_aux_drv drv = {
  90                 .bus    =       bus,
  91                 .addr   =       0x50,
  92                 .name   =       name,
  93                 .cleanup        =       cleanup,
  94                 .get_preferred_mode     =       get_preferred_mode};
  95
  96         query_edid(&drv);
  97
  98         /* as EDID devices can be connected/disconnected just add the driver */
  99         via_aux_add(&drv);
 100 }