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184a182e JS |
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(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(rtc->base + RTC_YEAR); | |
35 | reg1 = readl(rtc->base + RTC_TIME); | |
36 | } while (reg2 != readl(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(rtc->base + RTC_CTRL); | |
69 | writel(ctrl | RTC_UNLOCK, rtc->base + RTC_CTRL); | |
70 | ||
71 | writel(reg1, rtc->base + RTC_TIME); | |
72 | writel(reg2, rtc->base + RTC_YEAR); | |
73 | ||
74 | /* Re-lock and ensure enable is set now that a time is programmed */ | |
75 | writel(ctrl | RTC_ENABLE, 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; | |
184a182e JS |
88 | |
89 | rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); | |
90 | if (!rtc) | |
91 | return -ENOMEM; | |
92 | ||
09ef18bc | 93 | rtc->base = devm_platform_ioremap_resource(pdev, 0); |
184a182e JS |
94 | if (IS_ERR(rtc->base)) |
95 | return PTR_ERR(rtc->base); | |
96 | ||
97 | rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev); | |
98 | if (IS_ERR(rtc->rtc_dev)) | |
99 | return PTR_ERR(rtc->rtc_dev); | |
100 | ||
101 | platform_set_drvdata(pdev, 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 | ||
44c638ce | 107 | return rtc_register_device(rtc->rtc_dev); |
184a182e JS |
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 = of_match_ptr(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"); |