aboutsummaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-gemini.c
blob: 5279390bb42da84d5f477a3098d7af39c3599e8c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
/*
 *  Gemini OnChip RTC
 *
 *  Copyright (C) 2009 Janos Laube <janos.dev@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Original code for older kernel 2.6.15 are from Stormlinksemi
 * first update from Janos Laube for > 2.6.29 kernels
 *
 * checkpatch fixes and usage of rtc-lib code
 * Hans Ulli Kroll <ulli.kroll@googlemail.com>
 */

#include <linux/rtc.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/module.h>

#define DRV_NAME        "rtc-gemini"

MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
MODULE_DESCRIPTION("RTC driver for Gemini SoC");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);

struct gemini_rtc {
	struct rtc_device	*rtc_dev;
	void __iomem		*rtc_base;
	int			rtc_irq;
};

enum gemini_rtc_offsets {
	GEMINI_RTC_SECOND	= 0x00,
	GEMINI_RTC_MINUTE	= 0x04,
	GEMINI_RTC_HOUR		= 0x08,
	GEMINI_RTC_DAYS		= 0x0C,
	GEMINI_RTC_ALARM_SECOND	= 0x10,
	GEMINI_RTC_ALARM_MINUTE	= 0x14,
	GEMINI_RTC_ALARM_HOUR	= 0x18,
	GEMINI_RTC_RECORD	= 0x1C,
	GEMINI_RTC_CR		= 0x20
};

static irqreturn_t gemini_rtc_interrupt(int irq, void *dev)
{
	return IRQ_HANDLED;
}

/*
 * Looks like the RTC in the Gemini SoC is (totaly) broken
 * We can't read/write directly the time from RTC registers.
 * We must do some "offset" calculation to get the real time
 *
 * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
 * the same thing, without the rtc-lib.c calls.
 */

static int gemini_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct gemini_rtc *rtc = dev_get_drvdata(dev);

	unsigned int  days, hour, min, sec;
	unsigned long offset, time;

	sec  = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
	min  = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
	hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
	days = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
	offset = readl(rtc->rtc_base + GEMINI_RTC_RECORD);

	time = offset + days * 86400 + hour * 3600 + min * 60 + sec;

	rtc_time_to_tm(time, tm);

	return 0;
}

static int gemini_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct gemini_rtc *rtc = dev_get_drvdata(dev);
	unsigned int sec, min, hour, day;
	unsigned long offset, time;

	if (tm->tm_year >= 2148)	/* EPOCH Year + 179 */
		return -EINVAL;

	rtc_tm_to_time(tm, &time);

	sec = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
	min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
	hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
	day = readl(rtc->rtc_base + GEMINI_RTC_DAYS);

	offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);

	writel(offset, rtc->rtc_base + GEMINI_RTC_RECORD);
	writel(0x01, rtc->rtc_base + GEMINI_RTC_CR);

	return 0;
}

static const struct rtc_class_ops gemini_rtc_ops = {
	.read_time     = gemini_rtc_read_time,
	.set_time      = gemini_rtc_set_time,
};

static int gemini_rtc_probe(struct platform_device *pdev)
{
	struct gemini_rtc *rtc;
	struct device *dev = &pdev->dev;
	struct resource *res;
	int ret;

	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
	if (unlikely(!rtc))
		return -ENOMEM;
	platform_set_drvdata(pdev, rtc);

	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!res)
		return -ENODEV;

	rtc->rtc_irq = res->start;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENODEV;

	rtc->rtc_base = devm_ioremap(dev, res->start,
				     resource_size(res));
	if (!rtc->rtc_base)
		return -ENOMEM;

	ret = devm_request_irq(dev, rtc->rtc_irq, gemini_rtc_interrupt,
			       IRQF_SHARED, pdev->name, dev);
	if (unlikely(ret))
		return ret;

	rtc->rtc_dev = rtc_device_register(pdev->name, dev,
					   &gemini_rtc_ops, THIS_MODULE);
	return PTR_ERR_OR_ZERO(rtc->rtc_dev);
}

static int gemini_rtc_remove(struct platform_device *pdev)
{
	struct gemini_rtc *rtc = platform_get_drvdata(pdev);

	rtc_device_unregister(rtc->rtc_dev);

	return 0;
}

static const struct of_device_id gemini_rtc_dt_match[] = {
	{ .compatible = "cortina,gemini-rtc" },
	{ }
};
MODULE_DEVICE_TABLE(of, gemini_rtc_dt_match);

static struct platform_driver gemini_rtc_driver = {
	.driver		= {
		.name	= DRV_NAME,
		.of_match_table = gemini_rtc_dt_match,
	},
	.probe		= gemini_rtc_probe,
	.remove		= gemini_rtc_remove,
};

module_platform_driver_probe(gemini_rtc_driver, gemini_rtc_probe);