rtc-mv.c revision defb45147b85457461bfd3e57f0ecc05c18c429e 
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
16
17#define RTC_TIME_REG_OFFS	0
18#define RTC_SECONDS_OFFS	0
19#define RTC_MINUTES_OFFS	8
20#define RTC_HOURS_OFFS		16
21#define RTC_WDAY_OFFS		24
22#define RTC_HOURS_12H_MODE		(1 << 22) /* 12 hours mode */
23
24#define RTC_DATE_REG_OFFS	4
25#define RTC_MDAY_OFFS		0
26#define RTC_MONTH_OFFS		8
27#define RTC_YEAR_OFFS		16
28
29
30struct rtc_plat_data {
31	struct rtc_device *rtc;
32	void __iomem *ioaddr;
33};
34
35static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
36{
37	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
38	void __iomem *ioaddr = pdata->ioaddr;
39	u32	rtc_reg;
40
41	rtc_reg = (bin2bcd(tm->tm_sec) << RTC_SECONDS_OFFS) |
42		(bin2bcd(tm->tm_min) << RTC_MINUTES_OFFS) |
43		(bin2bcd(tm->tm_hour) << RTC_HOURS_OFFS) |
44		(bin2bcd(tm->tm_wday) << RTC_WDAY_OFFS);
45	writel(rtc_reg, ioaddr + RTC_TIME_REG_OFFS);
46
47	rtc_reg = (bin2bcd(tm->tm_mday) << RTC_MDAY_OFFS) |
48		(bin2bcd(tm->tm_mon + 1) << RTC_MONTH_OFFS) |
49		(bin2bcd(tm->tm_year % 100) << RTC_YEAR_OFFS);
50	writel(rtc_reg, ioaddr + RTC_DATE_REG_OFFS);
51
52	return 0;
53}
54
55static int mv_rtc_read_time(struct device *dev, struct rtc_time *tm)
56{
57	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
58	void __iomem *ioaddr = pdata->ioaddr;
59	u32	rtc_time, rtc_date;
60	unsigned int year, month, day, hour, minute, second, wday;
61
62	rtc_time = readl(ioaddr + RTC_TIME_REG_OFFS);
63	rtc_date = readl(ioaddr + RTC_DATE_REG_OFFS);
64
65	second = rtc_time & 0x7f;
66	minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;
67	hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hours mode */
68	wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;
69
70	day = rtc_date & 0x3f;
71	month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
72	year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;
73
74	tm->tm_sec = bcd2bin(second);
75	tm->tm_min = bcd2bin(minute);
76	tm->tm_hour = bcd2bin(hour);
77	tm->tm_mday = bcd2bin(day);
78	tm->tm_wday = bcd2bin(wday);
79	tm->tm_mon = bcd2bin(month) - 1;
80	/* hw counts from year 2000, but tm_year is relative to 1900 */
81	tm->tm_year = bcd2bin(year) + 100;
82
83	return rtc_valid_tm(tm);
84}
85
86static const struct rtc_class_ops mv_rtc_ops = {
87	.read_time	= mv_rtc_read_time,
88	.set_time	= mv_rtc_set_time,
89};
90
91static int __init mv_rtc_probe(struct platform_device *pdev)
92{
93	struct resource *res;
94	struct rtc_plat_data *pdata;
95	resource_size_t size;
96	u32 rtc_time;
97
98	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
99	if (!res)
100		return -ENODEV;
101
102	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
103	if (!pdata)
104		return -ENOMEM;
105
106	size = resource_size(res);
107	if (!devm_request_mem_region(&pdev->dev, res->start, size,
108				     pdev->name))
109		return -EBUSY;
110
111	pdata->ioaddr = devm_ioremap(&pdev->dev, res->start, size);
112	if (!pdata->ioaddr)
113		return -ENOMEM;
114
115	/* make sure the 24 hours mode is enabled */
116	rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
117	if (rtc_time & RTC_HOURS_12H_MODE) {
118		dev_err(&pdev->dev, "24 Hours mode not supported.\n");
119		return -EINVAL;
120	}
121
122	platform_set_drvdata(pdev, pdata);
123	pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
124					 &mv_rtc_ops, THIS_MODULE);
125	if (IS_ERR(pdata->rtc))
126		return PTR_ERR(pdata->rtc);
127
128	return 0;
129}
130
131static int __exit mv_rtc_remove(struct platform_device *pdev)
132{
133	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
134
135	rtc_device_unregister(pdata->rtc);
136	return 0;
137}
138
139static struct platform_driver mv_rtc_driver = {
140	.remove		= __exit_p(mv_rtc_remove),
141	.driver		= {
142		.name	= "rtc-mv",
143		.owner	= THIS_MODULE,
144	},
145};
146
147static __init int mv_init(void)
148{
149	return platform_driver_probe(&mv_rtc_driver, mv_rtc_probe);
150}
151
152static __exit void mv_exit(void)
153{
154	platform_driver_unregister(&mv_rtc_driver);
155}
156
157module_init(mv_init);
158module_exit(mv_exit);
159
160MODULE_AUTHOR("Saeed Bishara <saeed@marvell.com>");
161MODULE_DESCRIPTION("Marvell RTC driver");
162MODULE_LICENSE("GPL");
163MODULE_ALIAS("platform:rtc-mv");
164