1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Generic System Framebuffers
4 * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
5 */
6
7 /*
8 * Simple-Framebuffer support
9 * Create a platform-device for any available boot framebuffer. The
10 * simple-framebuffer platform device is already available on DT systems, so
11 * this module parses the global "screen_info" object and creates a suitable
12 * platform device compatible with the "simple-framebuffer" DT object. If
13 * the framebuffer is incompatible, we instead create a legacy
14 * "vesa-framebuffer", "efi-framebuffer" or "platform-framebuffer" device and
15 * pass the screen_info as platform_data. This allows legacy drivers
16 * to pick these devices up without messing with simple-framebuffer drivers.
17 * The global "screen_info" is still valid at all times.
18 *
19 * If CONFIG_SYSFB_SIMPLEFB is not selected, never register "simple-framebuffer"
20 * platform devices, but only use legacy framebuffer devices for
21 * backwards compatibility.
22 *
23 * TODO: We set the dev_id field of all platform-devices to 0. This allows
24 * other OF/DT parsers to create such devices, too. However, they must
25 * start at offset 1 for this to work.
26 */
27
28 #include <linux/err.h>
29 #include <linux/init.h>
30 #include <linux/kernel.h>
31 #include <linux/mm.h>
32 #include <linux/platform_data/simplefb.h>
33 #include <linux/platform_device.h>
34 #include <linux/screen_info.h>
35 #include <linux/sysfb.h>
36
sysfb_init(void)37 static __init int sysfb_init(void)
38 {
39 struct screen_info *si = &screen_info;
40 struct simplefb_platform_data mode;
41 struct platform_device *pd;
42 const char *name;
43 bool compatible;
44 int ret;
45
46 /* try to create a simple-framebuffer device */
47 compatible = sysfb_parse_mode(si, &mode);
48 if (compatible) {
49 ret = sysfb_create_simplefb(si, &mode);
50 if (!ret)
51 return 0;
52 }
53
54 /* if the FB is incompatible, create a legacy framebuffer device */
55 if (si->orig_video_isVGA == VIDEO_TYPE_EFI)
56 name = "efi-framebuffer";
57 else if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
58 name = "vesa-framebuffer";
59 else
60 name = "platform-framebuffer";
61
62 pd = platform_device_alloc(name, 0);
63 if (!pd)
64 return -ENOMEM;
65
66 sysfb_apply_efi_quirks(pd);
67
68 ret = platform_device_add_data(pd, si, sizeof(*si));
69 if (ret)
70 goto err;
71
72 ret = platform_device_add(pd);
73 if (ret)
74 goto err;
75
76 return 0;
77 err:
78 platform_device_put(pd);
79 return ret;
80 }
81
82 /* must execute after PCI subsystem for EFI quirks */
83 device_initcall(sysfb_init);
84