1 /*
2 * Gemini OnChip RTC
3 *
4 * Copyright (C) 2009 Janos Laube <janos.dev@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * Original code for older kernel 2.6.15 are from Stormlinksemi
17 * first update from Janos Laube for > 2.6.29 kernels
18 *
19 * checkpatch fixes and usage of rtc-lib code
20 * Hans Ulli Kroll <ulli.kroll@googlemail.com>
21 */
22
23 #include <linux/rtc.h>
24 #include <linux/io.h>
25 #include <linux/slab.h>
26 #include <linux/platform_device.h>
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29
30 #define DRV_NAME "rtc-gemini"
31 #define DRV_VERSION "0.2"
32
33 MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
34 MODULE_DESCRIPTION("RTC driver for Gemini SoC");
35 MODULE_LICENSE("GPL");
36 MODULE_ALIAS("platform:" DRV_NAME);
37
38 struct gemini_rtc {
39 struct rtc_device *rtc_dev;
40 void __iomem *rtc_base;
41 int rtc_irq;
42 };
43
44 enum gemini_rtc_offsets {
45 GEMINI_RTC_SECOND = 0x00,
46 GEMINI_RTC_MINUTE = 0x04,
47 GEMINI_RTC_HOUR = 0x08,
48 GEMINI_RTC_DAYS = 0x0C,
49 GEMINI_RTC_ALARM_SECOND = 0x10,
50 GEMINI_RTC_ALARM_MINUTE = 0x14,
51 GEMINI_RTC_ALARM_HOUR = 0x18,
52 GEMINI_RTC_RECORD = 0x1C,
53 GEMINI_RTC_CR = 0x20
54 };
55
gemini_rtc_interrupt(int irq,void * dev)56 static irqreturn_t gemini_rtc_interrupt(int irq, void *dev)
57 {
58 return IRQ_HANDLED;
59 }
60
61 /*
62 * Looks like the RTC in the Gemini SoC is (totaly) broken
63 * We can't read/write directly the time from RTC registers.
64 * We must do some "offset" calculation to get the real time
65 *
66 * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
67 * the same thing, without the rtc-lib.c calls.
68 */
69
gemini_rtc_read_time(struct device * dev,struct rtc_time * tm)70 static int gemini_rtc_read_time(struct device *dev, struct rtc_time *tm)
71 {
72 struct gemini_rtc *rtc = dev_get_drvdata(dev);
73
74 unsigned int days, hour, min, sec;
75 unsigned long offset, time;
76
77 sec = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
78 min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
79 hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
80 days = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
81 offset = readl(rtc->rtc_base + GEMINI_RTC_RECORD);
82
83 time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
84
85 rtc_time_to_tm(time, tm);
86
87 return 0;
88 }
89
gemini_rtc_set_time(struct device * dev,struct rtc_time * tm)90 static int gemini_rtc_set_time(struct device *dev, struct rtc_time *tm)
91 {
92 struct gemini_rtc *rtc = dev_get_drvdata(dev);
93 unsigned int sec, min, hour, day;
94 unsigned long offset, time;
95
96 if (tm->tm_year >= 2148) /* EPOCH Year + 179 */
97 return -EINVAL;
98
99 rtc_tm_to_time(tm, &time);
100
101 sec = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
102 min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
103 hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
104 day = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
105
106 offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
107
108 writel(offset, rtc->rtc_base + GEMINI_RTC_RECORD);
109 writel(0x01, rtc->rtc_base + GEMINI_RTC_CR);
110
111 return 0;
112 }
113
114 static struct rtc_class_ops gemini_rtc_ops = {
115 .read_time = gemini_rtc_read_time,
116 .set_time = gemini_rtc_set_time,
117 };
118
gemini_rtc_probe(struct platform_device * pdev)119 static int gemini_rtc_probe(struct platform_device *pdev)
120 {
121 struct gemini_rtc *rtc;
122 struct device *dev = &pdev->dev;
123 struct resource *res;
124 int ret;
125
126 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
127 if (unlikely(!rtc))
128 return -ENOMEM;
129 platform_set_drvdata(pdev, rtc);
130
131 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
132 if (!res)
133 return -ENODEV;
134
135 rtc->rtc_irq = res->start;
136
137 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
138 if (!res)
139 return -ENODEV;
140
141 rtc->rtc_base = devm_ioremap(dev, res->start,
142 resource_size(res));
143
144 ret = devm_request_irq(dev, rtc->rtc_irq, gemini_rtc_interrupt,
145 IRQF_SHARED, pdev->name, dev);
146 if (unlikely(ret))
147 return ret;
148
149 rtc->rtc_dev = rtc_device_register(pdev->name, dev,
150 &gemini_rtc_ops, THIS_MODULE);
151 return PTR_ERR_OR_ZERO(rtc->rtc_dev);
152 }
153
gemini_rtc_remove(struct platform_device * pdev)154 static int gemini_rtc_remove(struct platform_device *pdev)
155 {
156 struct gemini_rtc *rtc = platform_get_drvdata(pdev);
157
158 rtc_device_unregister(rtc->rtc_dev);
159 platform_set_drvdata(pdev, NULL);
160
161 return 0;
162 }
163
164 static struct platform_driver gemini_rtc_driver = {
165 .driver = {
166 .name = DRV_NAME,
167 },
168 .probe = gemini_rtc_probe,
169 .remove = gemini_rtc_remove,
170 };
171
172 module_platform_driver_probe(gemini_rtc_driver, gemini_rtc_probe);
173