1
2
3
4
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
15struct 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
29struct ds1216_priv {
30 struct rtc_device *rtc;
31 void __iomem *ioaddr;
32 size_t size;
33 unsigned long baseaddr;
34};
35
36static const u8 magic[] = {
37 0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c
38};
39
40
41
42
43
44
45static 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
58static 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
72static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr)
73{
74
75 readb(ioaddr);
76
77 ds1216_write(ioaddr, magic);
78}
79
80static 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 *)®s);
88
89 tm->tm_sec = bcd2bin(regs.sec);
90 tm->tm_min = bcd2bin(regs.min);
91 if (regs.hour & DS1216_HOUR_1224) {
92
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
108static 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 *)®s);
116
117 regs.tsec = 0;
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 *)®s);
134 return 0;
135}
136
137static const struct rtc_class_ops ds1216_rtc_ops = {
138 .read_time = ds1216_rtc_read_time,
139 .set_time = ds1216_rtc_set_time,
140};
141
142static 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
177 ds1216_read(priv->ioaddr, dummy);
178 return 0;
179
180out:
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
189static 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
200static 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
208static int __init ds1216_rtc_init(void)
209{
210 return platform_driver_probe(&ds1216_rtc_platform_driver, ds1216_rtc_probe);
211}
212
213static void __exit ds1216_rtc_exit(void)
214{
215 platform_driver_unregister(&ds1216_rtc_platform_driver);
216}
217
218MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
219MODULE_DESCRIPTION("DS1216 RTC driver");
220MODULE_LICENSE("GPL");
221MODULE_VERSION(DRV_VERSION);
222MODULE_ALIAS("platform:rtc-ds1216");
223
224module_init(ds1216_rtc_init);
225module_exit(ds1216_rtc_exit);
226