Merge branch 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6.git] / drivers / rtc / rtc-ds1216.c
1 /*
2  * Dallas DS1216 RTC driver
3  *
4  * Copyright (c) 2007 Thomas Bogendoerfer
5  *
6  */
7
8 #include <linux/module.h>
9 #include <linux/rtc.h>
10 #include <linux/platform_device.h>
11 #include <linux/bcd.h>
12
13 #define DRV_VERSION "0.2"
14
15 struct ds1216_regs {
16         u8 tsec;
17         u8 sec;
18         u8 min;
19         u8 hour;
20         u8 wday;
21         u8 mday;
22         u8 month;
23         u8 year;
24 };
25
26 #define DS1216_HOUR_1224        (1 << 7)
27 #define DS1216_HOUR_AMPM        (1 << 5)
28
29 struct ds1216_priv {
30         struct rtc_device *rtc;
31         void __iomem *ioaddr;
32         size_t size;
33         unsigned long baseaddr;
34 };
35
36 static const u8 magic[] = {
37         0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c
38 };
39
40 /*
41  * Read the 64 bit we'd like to have - It a series
42  * of 64 bits showing up in the LSB of the base register.
43  *
44  */
45 static void ds1216_read(u8 __iomem *ioaddr, u8 *buf)
46 {
47         unsigned char c;
48         int i, j;
49
50         for (i = 0; i < 8; i++) {
51                 c = 0;
52                 for (j = 0; j < 8; j++)
53                         c |= (readb(ioaddr) & 0x1) << j;
54                 buf[i] = c;
55         }
56 }
57
58 static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf)
59 {
60         unsigned char c;
61         int i, j;
62
63         for (i = 0; i < 8; i++) {
64                 c = buf[i];
65                 for (j = 0; j < 8; j++) {
66                         writeb(c, ioaddr);
67                         c = c >> 1;
68                 }
69         }
70 }
71
72 static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr)
73 {
74         /* Reset magic pointer */
75         readb(ioaddr);
76         /* Write 64 bit magic to DS1216 */
77         ds1216_write(ioaddr, magic);
78 }
79
80 static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm)
81 {
82         struct platform_device *pdev = to_platform_device(dev);
83         struct ds1216_priv *priv = platform_get_drvdata(pdev);
84         struct ds1216_regs regs;
85
86         ds1216_switch_ds_to_clock(priv->ioaddr);
87         ds1216_read(priv->ioaddr, (u8 *)&regs);
88
89         tm->tm_sec = bcd2bin(regs.sec);
90         tm->tm_min = bcd2bin(regs.min);
91         if (regs.hour & DS1216_HOUR_1224) {
92                 /* AM/PM mode */
93                 tm->tm_hour = bcd2bin(regs.hour & 0x1f);
94                 if (regs.hour & DS1216_HOUR_AMPM)
95                         tm->tm_hour += 12;
96         } else
97                 tm->tm_hour = bcd2bin(regs.hour & 0x3f);
98         tm->tm_wday = (regs.wday & 7) - 1;
99         tm->tm_mday = bcd2bin(regs.mday & 0x3f);
100         tm->tm_mon = bcd2bin(regs.month & 0x1f);
101         tm->tm_year = bcd2bin(regs.year);
102         if (tm->tm_year < 70)
103                 tm->tm_year += 100;
104
105         return rtc_valid_tm(tm);
106 }
107
108 static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm)
109 {
110         struct platform_device *pdev = to_platform_device(dev);
111         struct ds1216_priv *priv = platform_get_drvdata(pdev);
112         struct ds1216_regs regs;
113
114         ds1216_switch_ds_to_clock(priv->ioaddr);
115         ds1216_read(priv->ioaddr, (u8 *)&regs);
116
117         regs.tsec = 0; /* clear 0.1 and 0.01 seconds */
118         regs.sec = bin2bcd(tm->tm_sec);
119         regs.min = bin2bcd(tm->tm_min);
120         regs.hour &= DS1216_HOUR_1224;
121         if (regs.hour && tm->tm_hour > 12) {
122                 regs.hour |= DS1216_HOUR_AMPM;
123                 tm->tm_hour -= 12;
124         }
125         regs.hour |= bin2bcd(tm->tm_hour);
126         regs.wday &= ~7;
127         regs.wday |= tm->tm_wday;
128         regs.mday = bin2bcd(tm->tm_mday);
129         regs.month = bin2bcd(tm->tm_mon);
130         regs.year = bin2bcd(tm->tm_year % 100);
131
132         ds1216_switch_ds_to_clock(priv->ioaddr);
133         ds1216_write(priv->ioaddr, (u8 *)&regs);
134         return 0;
135 }
136
137 static const struct rtc_class_ops ds1216_rtc_ops = {
138         .read_time      = ds1216_rtc_read_time,
139         .set_time       = ds1216_rtc_set_time,
140 };
141
142 static int __init ds1216_rtc_probe(struct platform_device *pdev)
143 {
144         struct resource *res;
145         struct ds1216_priv *priv;
146         int ret = 0;
147         u8 dummy[8];
148
149         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
150         if (!res)
151                 return -ENODEV;
152         priv = kzalloc(sizeof *priv, GFP_KERNEL);
153         if (!priv)
154                 return -ENOMEM;
155
156         platform_set_drvdata(pdev, priv);
157
158         priv->size = resource_size(res);
159         if (!request_mem_region(res->start, priv->size, pdev->name)) {
160                 ret = -EBUSY;
161                 goto out;
162         }
163         priv->baseaddr = res->start;
164         priv->ioaddr = ioremap(priv->baseaddr, priv->size);
165         if (!priv->ioaddr) {
166                 ret = -ENOMEM;
167                 goto out;
168         }
169         priv->rtc = rtc_device_register("ds1216", &pdev->dev,
170                                   &ds1216_rtc_ops, THIS_MODULE);
171         if (IS_ERR(priv->rtc)) {
172                 ret = PTR_ERR(priv->rtc);
173                 goto out;
174         }
175
176         /* dummy read to get clock into a known state */
177         ds1216_read(priv->ioaddr, dummy);
178         return 0;
179
180 out:
181         if (priv->ioaddr)
182                 iounmap(priv->ioaddr);
183         if (priv->baseaddr)
184                 release_mem_region(priv->baseaddr, priv->size);
185         kfree(priv);
186         return ret;
187 }
188
189 static int __exit ds1216_rtc_remove(struct platform_device *pdev)
190 {
191         struct ds1216_priv *priv = platform_get_drvdata(pdev);
192
193         rtc_device_unregister(priv->rtc);
194         iounmap(priv->ioaddr);
195         release_mem_region(priv->baseaddr, priv->size);
196         kfree(priv);
197         return 0;
198 }
199
200 static struct platform_driver ds1216_rtc_platform_driver = {
201         .driver         = {
202                 .name   = "rtc-ds1216",
203                 .owner  = THIS_MODULE,
204         },
205         .remove         = __exit_p(ds1216_rtc_remove),
206 };
207
208 static int __init ds1216_rtc_init(void)
209 {
210         return platform_driver_probe(&ds1216_rtc_platform_driver, ds1216_rtc_probe);
211 }
212
213 static void __exit ds1216_rtc_exit(void)
214 {
215         platform_driver_unregister(&ds1216_rtc_platform_driver);
216 }
217
218 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
219 MODULE_DESCRIPTION("DS1216 RTC driver");
220 MODULE_LICENSE("GPL");
221 MODULE_VERSION(DRV_VERSION);
222 MODULE_ALIAS("platform:rtc-ds1216");
223
224 module_init(ds1216_rtc_init);
225 module_exit(ds1216_rtc_exit);