1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 2011 Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
4 */
5/*
6 * generic EDID driver
7 */
8
9#include <linux/slab.h>
10#include <linux/fb.h>
11#include "via_aux.h"
12#include "../edid.h"
13
14
15static const char *name = "EDID";
16
17
18static void query_edid(struct via_aux_drv *drv)
19{
20 struct fb_monspecs *spec = drv->data;
21 unsigned char edid[EDID_LENGTH];
22 bool valid = false;
23
24 if (spec) {
25 fb_destroy_modedb(modedb: spec->modedb);
26 } else {
27 spec = kmalloc(size: sizeof(*spec), GFP_KERNEL);
28 if (!spec)
29 return;
30 }
31
32 spec->version = spec->revision = 0;
33 if (via_aux_read(drv, start: 0x00, buf: edid, EDID_LENGTH)) {
34 fb_edid_to_monspecs(edid, specs: spec);
35 valid = spec->version || spec->revision;
36 }
37
38 if (!valid) {
39 kfree(objp: spec);
40 spec = NULL;
41 } else
42 printk(KERN_DEBUG "EDID: %s %s\n", spec->manufacturer, spec->monitor);
43
44 drv->data = spec;
45}
46
47static const struct fb_videomode *get_preferred_mode(struct via_aux_drv *drv)
48{
49 struct fb_monspecs *spec = drv->data;
50 int i;
51
52 if (!spec || !spec->modedb || !(spec->misc & FB_MISC_1ST_DETAIL))
53 return NULL;
54
55 for (i = 0; i < spec->modedb_len; i++) {
56 if (spec->modedb[i].flag & FB_MODE_IS_FIRST &&
57 spec->modedb[i].flag & FB_MODE_IS_DETAILED)
58 return &spec->modedb[i];
59 }
60
61 return NULL;
62}
63
64static void cleanup(struct via_aux_drv *drv)
65{
66 struct fb_monspecs *spec = drv->data;
67
68 if (spec)
69 fb_destroy_modedb(modedb: spec->modedb);
70}
71
72void via_aux_edid_probe(struct via_aux_bus *bus)
73{
74 struct via_aux_drv drv = {
75 .bus = bus,
76 .addr = 0x50,
77 .name = name,
78 .cleanup = cleanup,
79 .get_preferred_mode = get_preferred_mode};
80
81 query_edid(drv: &drv);
82
83 /* as EDID devices can be connected/disconnected just add the driver */
84 via_aux_add(drv: &drv);
85}
86

source code of linux/drivers/video/fbdev/via/via_aux_edid.c