1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Support for OLPC XO-1 Real Time Clock (RTC)
4  *
5  * Copyright (C) 2011 One Laptop per Child
6  */
7 
8 #include <linux/mc146818rtc.h>
9 #include <linux/platform_device.h>
10 #include <linux/rtc.h>
11 #include <linux/of.h>
12 
13 #include <asm/msr.h>
14 #include <asm/olpc.h>
15 #include <asm/x86_init.h>
16 
17 static void rtc_wake_on(struct device *dev)
18 {
19 	olpc_xo1_pm_wakeup_set(CS5536_PM_RTC);
20 }
21 
22 static void rtc_wake_off(struct device *dev)
23 {
24 	olpc_xo1_pm_wakeup_clear(CS5536_PM_RTC);
25 }
26 
27 static struct resource rtc_platform_resource[] = {
28 	[0] = {
29 		.start	= RTC_PORT(0),
30 		.end	= RTC_PORT(1),
31 		.flags	= IORESOURCE_IO,
32 	},
33 	[1] = {
34 		.start	= RTC_IRQ,
35 		.end	= RTC_IRQ,
36 		.flags	= IORESOURCE_IRQ,
37 	}
38 };
39 
40 static struct cmos_rtc_board_info rtc_info = {
41 	.rtc_day_alarm = 0,
42 	.rtc_mon_alarm = 0,
43 	.rtc_century = 0,
44 	.wake_on = rtc_wake_on,
45 	.wake_off = rtc_wake_off,
46 };
47 
48 static struct platform_device xo1_rtc_device = {
49 	.name = "rtc_cmos",
50 	.id = -1,
51 	.num_resources = ARRAY_SIZE(rtc_platform_resource),
52 	.dev.platform_data = &rtc_info,
53 	.resource = rtc_platform_resource,
54 };
55 
56 static int __init xo1_rtc_init(void)
57 {
58 	int r;
59 	struct device_node *node;
60 
61 	node = of_find_compatible_node(NULL, NULL, "olpc,xo1-rtc");
62 	if (!node)
63 		return 0;
64 	of_node_put(node);
65 
66 	pr_info("olpc-xo1-rtc: Initializing OLPC XO-1 RTC\n");
67 	rdmsrl(MSR_RTC_DOMA_OFFSET, rtc_info.rtc_day_alarm);
68 	rdmsrl(MSR_RTC_MONA_OFFSET, rtc_info.rtc_mon_alarm);
69 	rdmsrl(MSR_RTC_CEN_OFFSET, rtc_info.rtc_century);
70 
71 	r = platform_device_register(&xo1_rtc_device);
72 	if (r)
73 		return r;
74 
75 	x86_platform.legacy.rtc = 0;
76 
77 	device_init_wakeup(&xo1_rtc_device.dev, 1);
78 	return 0;
79 }
80 arch_initcall(xo1_rtc_init);
81