tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
32MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
33MODULE_DESCRIPTION("RTC driver for Gemini SoC");
34MODULE_LICENSE("GPL");
35MODULE_ALIAS("platform:" DRV_NAME);
36
37struct gemini_rtc {
38 struct rtc_device *rtc_dev;
39 void __iomem *rtc_base;
40 int rtc_irq;
41};
42
43enum gemini_rtc_offsets {
44 GEMINI_RTC_SECOND = 0x00,
45 GEMINI_RTC_MINUTE = 0x04,
46 GEMINI_RTC_HOUR = 0x08,
47 GEMINI_RTC_DAYS = 0x0C,
48 GEMINI_RTC_ALARM_SECOND = 0x10,
49 GEMINI_RTC_ALARM_MINUTE = 0x14,
50 GEMINI_RTC_ALARM_HOUR = 0x18,
51 GEMINI_RTC_RECORD = 0x1C,
52 GEMINI_RTC_CR = 0x20
53};
54
55static irqreturn_t gemini_rtc_interrupt(int irq, void *dev)
56{
57 return IRQ_HANDLED;
58}
59
60/*
61 * Looks like the RTC in the Gemini SoC is (totaly) broken
62 * We can't read/write directly the time from RTC registers.
63 * We must do some "offset" calculation to get the real time
64 *
65 * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
66 * the same thing, without the rtc-lib.c calls.
67 */
68
69static int gemini_rtc_read_time(struct device *dev, struct rtc_time *tm)
70{
71 struct gemini_rtc *rtc = dev_get_drvdata(dev);
72
73 unsigned int days, hour, min, sec;
74 unsigned long offset, time;
75
76 sec = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
77 min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
78 hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
79 days = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
80 offset = readl(rtc->rtc_base + GEMINI_RTC_RECORD);
81
82 time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
83
84 rtc_time_to_tm(time, tm);
85
86 return 0;
87}
88
89static int gemini_rtc_set_time(struct device *dev, struct rtc_time *tm)
90{
91 struct gemini_rtc *rtc = dev_get_drvdata(dev);
92 unsigned int sec, min, hour, day;
93 unsigned long offset, time;
94
95 if (tm->tm_year >= 2148) /* EPOCH Year + 179 */
96 return -EINVAL;
97
98 rtc_tm_to_time(tm, &time);
99
100 sec = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
101 min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
102 hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
103 day = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
104
105 offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
106
107 writel(offset, rtc->rtc_base + GEMINI_RTC_RECORD);
108 writel(0x01, rtc->rtc_base + GEMINI_RTC_CR);
109
110 return 0;
111}
112
113static const struct rtc_class_ops gemini_rtc_ops = {
114 .read_time = gemini_rtc_read_time,
115 .set_time = gemini_rtc_set_time,
116};
117
118static int gemini_rtc_probe(struct platform_device *pdev)
119{
120 struct gemini_rtc *rtc;
121 struct device *dev = &pdev->dev;
122 struct resource *res;
123 int ret;
124
125 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
126 if (unlikely(!rtc))
127 return -ENOMEM;
128 platform_set_drvdata(pdev, rtc);
129
130 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
131 if (!res)
132 return -ENODEV;
133
134 rtc->rtc_irq = res->start;
135
136 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
137 if (!res)
138 return -ENODEV;
139
140 rtc->rtc_base = devm_ioremap(dev, res->start,
141 resource_size(res));
142
143 ret = devm_request_irq(dev, rtc->rtc_irq, gemini_rtc_interrupt,
144 IRQF_SHARED, pdev->name, dev);
145 if (unlikely(ret))
146 return ret;
147
148 rtc->rtc_dev = rtc_device_register(pdev->name, dev,
149 &gemini_rtc_ops, THIS_MODULE);
150 return PTR_ERR_OR_ZERO(rtc->rtc_dev);
151}
152
153static int gemini_rtc_remove(struct platform_device *pdev)
154{
155 struct gemini_rtc *rtc = platform_get_drvdata(pdev);
156
157 rtc_device_unregister(rtc->rtc_dev);
158
159 return 0;
160}
161
162static const struct of_device_id gemini_rtc_dt_match[] = {
163 { .compatible = "cortina,gemini-rtc" },
164 { }
165};
166MODULE_DEVICE_TABLE(of, gemini_rtc_dt_match);
167
168static struct platform_driver gemini_rtc_driver = {
169 .driver = {
170 .name = DRV_NAME,
171 .of_match_table = gemini_rtc_dt_match,
172 },
173 .probe = gemini_rtc_probe,
174 .remove = gemini_rtc_remove,
175};
176
177module_platform_driver_probe(gemini_rtc_driver, gemini_rtc_probe);