rtc-mv.c revision 9d1d4f9eabbca276a2a618a94ed3149d5971063e 
1/*
2 * Driver for the RTC in Marvell SoCs.
3 *
4 * This file is licensed under the terms of the GNU General Public
5 * License version 2.  This program is licensed "as is" without any
6 * warranty of any kind, whether express or implied.
7 */
8
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/rtc.h>
12#include <linux/bcd.h>
13#include <linux/io.h>
14#include <linux/platform_device.h>
15#include <linux/delay.h>
16
17
18#define RTC_TIME_REG_OFFS	0
19#define RTC_SECONDS_OFFS	0
20#define RTC_MINUTES_OFFS	8
21#define RTC_HOURS_OFFS		16
22#define RTC_WDAY_OFFS		24
23#define RTC_HOURS_12H_MODE		(1 << 22) /* 12 hours mode */
24
25#define RTC_DATE_REG_OFFS	4
26#define RTC_MDAY_OFFS		0
27#define RTC_MONTH_OFFS		8
28#define RTC_YEAR_OFFS		16
29
30
31struct rtc_plat_data {
32	struct rtc_device *rtc;
33	void __iomem *ioaddr;
34};
35
36static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
37{
38	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
39	void __iomem *ioaddr = pdata->ioaddr;
40	u32	rtc_reg;
41
42	rtc_reg = (bin2bcd(tm->tm_sec) << RTC_SECONDS_OFFS) |
43		(bin2bcd(tm->tm_min) << RTC_MINUTES_OFFS) |
44		(bin2bcd(tm->tm_hour) << RTC_HOURS_OFFS) |
45		(bin2bcd(tm->tm_wday) << RTC_WDAY_OFFS);
46	writel(rtc_reg, ioaddr + RTC_TIME_REG_OFFS);
47
48	rtc_reg = (bin2bcd(tm->tm_mday) << RTC_MDAY_OFFS) |
49		(bin2bcd(tm->tm_mon + 1) << RTC_MONTH_OFFS) |
50		(bin2bcd(tm->tm_year % 100) << RTC_YEAR_OFFS);
51	writel(rtc_reg, ioaddr + RTC_DATE_REG_OFFS);
52
53	return 0;
54}
55
56static int mv_rtc_read_time(struct device *dev, struct rtc_time *tm)
57{
58	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
59	void __iomem *ioaddr = pdata->ioaddr;
60	u32	rtc_time, rtc_date;
61	unsigned int year, month, day, hour, minute, second, wday;
62
63	rtc_time = readl(ioaddr + RTC_TIME_REG_OFFS);
64	rtc_date = readl(ioaddr + RTC_DATE_REG_OFFS);
65
66	second = rtc_time & 0x7f;
67	minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;
68	hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hours mode */
69	wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;
70
71	day = rtc_date & 0x3f;
72	month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
73	year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;
74
75	tm->tm_sec = bcd2bin(second);
76	tm->tm_min = bcd2bin(minute);
77	tm->tm_hour = bcd2bin(hour);
78	tm->tm_mday = bcd2bin(day);
79	tm->tm_wday = bcd2bin(wday);
80	tm->tm_mon = bcd2bin(month) - 1;
81	/* hw counts from year 2000, but tm_year is relative to 1900 */
82	tm->tm_year = bcd2bin(year) + 100;
83
84	return rtc_valid_tm(tm);
85}
86
87static const struct rtc_class_ops mv_rtc_ops = {
88	.read_time	= mv_rtc_read_time,
89	.set_time	= mv_rtc_set_time,
90};
91
92static int __init mv_rtc_probe(struct platform_device *pdev)
93{
94	struct resource *res;
95	struct rtc_plat_data *pdata;
96	resource_size_t size;
97	u32 rtc_time;
98
99	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
100	if (!res)
101		return -ENODEV;
102
103	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
104	if (!pdata)
105		return -ENOMEM;
106
107	size = resource_size(res);
108	if (!devm_request_mem_region(&pdev->dev, res->start, size,
109				     pdev->name))
110		return -EBUSY;
111
112	pdata->ioaddr = devm_ioremap(&pdev->dev, res->start, size);
113	if (!pdata->ioaddr)
114		return -ENOMEM;
115
116	/* make sure the 24 hours mode is enabled */
117	rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
118	if (rtc_time & RTC_HOURS_12H_MODE) {
119		dev_err(&pdev->dev, "24 Hours mode not supported.\n");
120		return -EINVAL;
121	}
122
123	/* make sure it is actually functional */
124	if (rtc_time == 0x01000000) {
125		ssleep(1);
126		rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
127		if (rtc_time == 0x01000000) {
128			dev_err(&pdev->dev, "internal RTC not ticking\n");
129			return -ENODEV;
130		}
131	}
132
133	platform_set_drvdata(pdev, pdata);
134	pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
135					 &mv_rtc_ops, THIS_MODULE);
136	if (IS_ERR(pdata->rtc))
137		return PTR_ERR(pdata->rtc);
138
139	return 0;
140}
141
142static int __exit mv_rtc_remove(struct platform_device *pdev)
143{
144	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
145
146	rtc_device_unregister(pdata->rtc);
147	return 0;
148}
149
150static struct platform_driver mv_rtc_driver = {
151	.remove		= __exit_p(mv_rtc_remove),
152	.driver		= {
153		.name	= "rtc-mv",
154		.owner	= THIS_MODULE,
155	},
156};
157
158static __init int mv_init(void)
159{
160	return platform_driver_probe(&mv_rtc_driver, mv_rtc_probe);
161}
162
163static __exit void mv_exit(void)
164{
165	platform_driver_unregister(&mv_rtc_driver);
166}
167
168module_init(mv_init);
169module_exit(mv_exit);
170
171MODULE_AUTHOR("Saeed Bishara <saeed@marvell.com>");
172MODULE_DESCRIPTION("Marvell RTC driver");
173MODULE_LICENSE("GPL");
174MODULE_ALIAS("platform:rtc-mv");
175