xref: /openbmc/linux/drivers/firmware/sysfb.c (revision de6da33e)
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 
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