1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | // Copyright 2015 IBM Corp. |
3 | |
4 | #include <linux/module.h> |
5 | #include <linux/of.h> |
6 | #include <linux/platform_device.h> |
7 | #include <linux/rtc.h> |
8 | #include <linux/io.h> |
9 | |
10 | struct aspeed_rtc { |
11 | struct rtc_device *rtc_dev; |
12 | void __iomem *base; |
13 | }; |
14 | |
15 | #define RTC_TIME 0x00 |
16 | #define RTC_YEAR 0x04 |
17 | #define RTC_CTRL 0x10 |
18 | |
19 | #define RTC_UNLOCK BIT(1) |
20 | #define RTC_ENABLE BIT(0) |
21 | |
22 | static int aspeed_rtc_read_time(struct device *dev, struct rtc_time *tm) |
23 | { |
24 | struct aspeed_rtc *rtc = dev_get_drvdata(dev); |
25 | unsigned int cent, year; |
26 | u32 reg1, reg2; |
27 | |
28 | if (!(readl(addr: rtc->base + RTC_CTRL) & RTC_ENABLE)) { |
29 | dev_dbg(dev, "%s failing as rtc disabled\n" , __func__); |
30 | return -EINVAL; |
31 | } |
32 | |
33 | do { |
34 | reg2 = readl(addr: rtc->base + RTC_YEAR); |
35 | reg1 = readl(addr: rtc->base + RTC_TIME); |
36 | } while (reg2 != readl(addr: rtc->base + RTC_YEAR)); |
37 | |
38 | tm->tm_mday = (reg1 >> 24) & 0x1f; |
39 | tm->tm_hour = (reg1 >> 16) & 0x1f; |
40 | tm->tm_min = (reg1 >> 8) & 0x3f; |
41 | tm->tm_sec = (reg1 >> 0) & 0x3f; |
42 | |
43 | cent = (reg2 >> 16) & 0x1f; |
44 | year = (reg2 >> 8) & 0x7f; |
45 | tm->tm_mon = ((reg2 >> 0) & 0x0f) - 1; |
46 | tm->tm_year = year + (cent * 100) - 1900; |
47 | |
48 | dev_dbg(dev, "%s %ptR" , __func__, tm); |
49 | |
50 | return 0; |
51 | } |
52 | |
53 | static int aspeed_rtc_set_time(struct device *dev, struct rtc_time *tm) |
54 | { |
55 | struct aspeed_rtc *rtc = dev_get_drvdata(dev); |
56 | u32 reg1, reg2, ctrl; |
57 | int year, cent; |
58 | |
59 | cent = (tm->tm_year + 1900) / 100; |
60 | year = tm->tm_year % 100; |
61 | |
62 | reg1 = (tm->tm_mday << 24) | (tm->tm_hour << 16) | (tm->tm_min << 8) | |
63 | tm->tm_sec; |
64 | |
65 | reg2 = ((cent & 0x1f) << 16) | ((year & 0x7f) << 8) | |
66 | ((tm->tm_mon + 1) & 0xf); |
67 | |
68 | ctrl = readl(addr: rtc->base + RTC_CTRL); |
69 | writel(val: ctrl | RTC_UNLOCK, addr: rtc->base + RTC_CTRL); |
70 | |
71 | writel(val: reg1, addr: rtc->base + RTC_TIME); |
72 | writel(val: reg2, addr: rtc->base + RTC_YEAR); |
73 | |
74 | /* Re-lock and ensure enable is set now that a time is programmed */ |
75 | writel(val: ctrl | RTC_ENABLE, addr: rtc->base + RTC_CTRL); |
76 | |
77 | return 0; |
78 | } |
79 | |
80 | static const struct rtc_class_ops aspeed_rtc_ops = { |
81 | .read_time = aspeed_rtc_read_time, |
82 | .set_time = aspeed_rtc_set_time, |
83 | }; |
84 | |
85 | static int aspeed_rtc_probe(struct platform_device *pdev) |
86 | { |
87 | struct aspeed_rtc *rtc; |
88 | |
89 | rtc = devm_kzalloc(dev: &pdev->dev, size: sizeof(*rtc), GFP_KERNEL); |
90 | if (!rtc) |
91 | return -ENOMEM; |
92 | |
93 | rtc->base = devm_platform_ioremap_resource(pdev, index: 0); |
94 | if (IS_ERR(ptr: rtc->base)) |
95 | return PTR_ERR(ptr: rtc->base); |
96 | |
97 | rtc->rtc_dev = devm_rtc_allocate_device(dev: &pdev->dev); |
98 | if (IS_ERR(ptr: rtc->rtc_dev)) |
99 | return PTR_ERR(ptr: rtc->rtc_dev); |
100 | |
101 | platform_set_drvdata(pdev, data: rtc); |
102 | |
103 | rtc->rtc_dev->ops = &aspeed_rtc_ops; |
104 | rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_1900; |
105 | rtc->rtc_dev->range_max = 38814989399LL; /* 3199-12-31 23:59:59 */ |
106 | |
107 | return devm_rtc_register_device(rtc->rtc_dev); |
108 | } |
109 | |
110 | static const struct of_device_id aspeed_rtc_match[] = { |
111 | { .compatible = "aspeed,ast2400-rtc" , }, |
112 | { .compatible = "aspeed,ast2500-rtc" , }, |
113 | { .compatible = "aspeed,ast2600-rtc" , }, |
114 | {} |
115 | }; |
116 | MODULE_DEVICE_TABLE(of, aspeed_rtc_match); |
117 | |
118 | static struct platform_driver aspeed_rtc_driver = { |
119 | .driver = { |
120 | .name = "aspeed-rtc" , |
121 | .of_match_table = aspeed_rtc_match, |
122 | }, |
123 | }; |
124 | |
125 | module_platform_driver_probe(aspeed_rtc_driver, aspeed_rtc_probe); |
126 | |
127 | MODULE_DESCRIPTION("ASPEED RTC driver" ); |
128 | MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>" ); |
129 | MODULE_LICENSE("GPL" ); |
130 | |