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
15 static const char *name = "EDID";
16
17
query_edid(struct via_aux_drv * drv)18 static 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(spec->modedb);
26 } else {
27 spec = kmalloc(sizeof(*spec), GFP_KERNEL);
28 if (!spec)
29 return;
30 }
31
32 spec->version = spec->revision = 0;
33 if (via_aux_read(drv, 0x00, edid, EDID_LENGTH)) {
34 fb_edid_to_monspecs(edid, spec);
35 valid = spec->version || spec->revision;
36 }
37
38 if (!valid) {
39 kfree(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
get_preferred_mode(struct via_aux_drv * drv)47 static 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
cleanup(struct via_aux_drv * drv)64 static void cleanup(struct via_aux_drv *drv)
65 {
66 struct fb_monspecs *spec = drv->data;
67
68 if (spec)
69 fb_destroy_modedb(spec->modedb);
70 }
71
via_aux_edid_probe(struct via_aux_bus * bus)72 void 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);
82
83 /* as EDID devices can be connected/disconnected just add the driver */
84 via_aux_add(&drv);
85 }
86