drivers/rtc/: use bcd2bin/bin2bcd
[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 "0.1"
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         return 0;
105 }
106
107 static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm)
108 {
109         struct platform_device *pdev = to_platform_device(dev);
110         struct ds1216_priv *priv = platform_get_drvdata(pdev);
111         struct ds1216_regs regs;
112
113         ds1216_switch_ds_to_clock(priv->ioaddr);
114         ds1216_read(priv->ioaddr, (u8 *)&regs);
115
116         regs.tsec = 0; /* clear 0.1 and 0.01 seconds */
117         regs.sec = bin2bcd(tm->tm_sec);
118         regs.min = bin2bcd(tm->tm_min);
119         regs.hour &= DS1216_HOUR_1224;
120         if (regs.hour && tm->tm_hour > 12) {
121                 regs.hour |= DS1216_HOUR_AMPM;
122                 tm->tm_hour -= 12;
123         }
124         regs.hour |= bin2bcd(tm->tm_hour);
125         regs.wday &= ~7;
126         regs.wday |= tm->tm_wday;
127         regs.mday = bin2bcd(tm->tm_mday);
128         regs.month = bin2bcd(tm->tm_mon);
129         regs.year = bin2bcd(tm->tm_year % 100);
130
131         ds1216_switch_ds_to_clock(priv->ioaddr);
132         ds1216_write(priv->ioaddr, (u8 *)&regs);
133         return 0;
134 }
135
136 static const struct rtc_class_ops ds1216_rtc_ops = {
137         .read_time      = ds1216_rtc_read_time,
138         .set_time       = ds1216_rtc_set_time,
139 };
140
141 static int __devinit ds1216_rtc_probe(struct platform_device *pdev)
142 {
143         struct rtc_device *rtc;
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         priv->size = res->end - res->start + 1;
156         if (!request_mem_region(res->start, priv->size, pdev->name)) {
157                 ret = -EBUSY;
158                 goto out;
159         }
160         priv->baseaddr = res->start;
161         priv->ioaddr = ioremap(priv->baseaddr, priv->size);
162         if (!priv->ioaddr) {
163                 ret = -ENOMEM;
164                 goto out;
165         }
166         rtc = rtc_device_register("ds1216", &pdev->dev,
167                                   &ds1216_rtc_ops, THIS_MODULE);
168         if (IS_ERR(rtc)) {
169                 ret = PTR_ERR(rtc);
170                 goto out;
171         }
172         priv->rtc = rtc;
173         platform_set_drvdata(pdev, priv);
174
175         /* dummy read to get clock into a known state */
176         ds1216_read(priv->ioaddr, dummy);
177         return 0;
178
179 out:
180         if (priv->rtc)
181                 rtc_device_unregister(priv->rtc);
182         if (priv->ioaddr)
183                 iounmap(priv->ioaddr);
184         if (priv->baseaddr)
185                 release_mem_region(priv->baseaddr, priv->size);
186         kfree(priv);
187         return ret;
188 }
189
190 static int __devexit ds1216_rtc_remove(struct platform_device *pdev)
191 {
192         struct ds1216_priv *priv = platform_get_drvdata(pdev);
193
194         rtc_device_unregister(priv->rtc);
195         iounmap(priv->ioaddr);
196         release_mem_region(priv->baseaddr, priv->size);
197         kfree(priv);
198         return 0;
199 }
200
201 static struct platform_driver ds1216_rtc_platform_driver = {
202         .driver         = {
203                 .name   = "rtc-ds1216",
204                 .owner  = THIS_MODULE,
205         },
206         .probe          = ds1216_rtc_probe,
207         .remove         = __devexit_p(ds1216_rtc_remove),
208 };
209
210 static int __init ds1216_rtc_init(void)
211 {
212         return platform_driver_register(&ds1216_rtc_platform_driver);
213 }
214
215 static void __exit ds1216_rtc_exit(void)
216 {
217         platform_driver_unregister(&ds1216_rtc_platform_driver);
218 }
219
220 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
221 MODULE_DESCRIPTION("DS1216 RTC driver");
222 MODULE_LICENSE("GPL");
223 MODULE_VERSION(DRV_VERSION);
224 MODULE_ALIAS("platform:rtc-ds1216");
225
226 module_init(ds1216_rtc_init);
227 module_exit(ds1216_rtc_exit);