via_aux_edid.c

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/*
 * Copyright 2011 Florian Tobias Schandinat <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation;
 * either version 2, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTIES OR REPRESENTATIONS; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE.See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
/*
 * generic EDID driver
 */

#include <linux/slab.h>
#include <linux/fb.h>
#include "via_aux.h"
#include "../edid.h"


static const char *name = "EDID";


static void query_edid(struct via_aux_drv *drv)
{
    struct fb_monspecs *spec = drv->data;
    unsigned char edid[EDID_LENGTH];
    bool valid = false;

    if (spec) {
        fb_destroy_modedb(spec->modedb);
    } else {
        spec = kmalloc(sizeof(*spec), GFP_KERNEL);
        if (!spec)
            return;
    }

    spec->version = spec->revision = 0;
    if (via_aux_read(drv, 0x00, edid, EDID_LENGTH)) {
        fb_edid_to_monspecs(edid, spec);
        valid = spec->version || spec->revision;
    }

    if (!valid) {
        kfree(spec);
        spec = NULL;
    } else
        printk(KERN_DEBUG "EDID: %s %s\n", spec->manufacturer, spec->monitor);

    drv->data = spec;
}

static const struct fb_videomode *get_preferred_mode(struct via_aux_drv *drv)
{
    struct fb_monspecs *spec = drv->data;
    int i;

    if (!spec || !spec->modedb || !(spec->misc & FB_MISC_1ST_DETAIL))
        return NULL;

    for (i = 0; i < spec->modedb_len; i++) {
        if (spec->modedb[i].flag & FB_MODE_IS_FIRST &&
            spec->modedb[i].flag & FB_MODE_IS_DETAILED)
            return &spec->modedb[i];
    }

    return NULL;
}

static void cleanup(struct via_aux_drv *drv)
{
    struct fb_monspecs *spec = drv->data;

    if (spec)
        fb_destroy_modedb(spec->modedb);
}

void via_aux_edid_probe(struct via_aux_bus *bus)
{
    struct via_aux_drv drv = {
        .bus    =   bus,
        .addr   =   0x50,
        .name   =   name,
        .cleanup    =   cleanup,
        .get_preferred_mode =   get_preferred_mode};

    query_edid(&drv);

    /* as EDID devices can be connected/disconnected just add the driver */
    via_aux_add(&drv);
}