tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
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 * 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 */
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 /* Reset magic pointer */
75 readb(ioaddr);
76 /* Write 64 bit magic to DS1216 */
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 /* 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
107static 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 *)®s);
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 *)®s);
133 return 0;
134}
135
136static const struct rtc_class_ops ds1216_rtc_ops = {
137 .read_time = ds1216_rtc_read_time,
138 .set_time = ds1216_rtc_set_time,
139};
140
141static 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
179out:
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
190static 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
201static 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
210static int __init ds1216_rtc_init(void)
211{
212 return platform_driver_register(&ds1216_rtc_platform_driver);
213}
214
215static void __exit ds1216_rtc_exit(void)
216{
217 platform_driver_unregister(&ds1216_rtc_platform_driver);
218}
219
220MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
221MODULE_DESCRIPTION("DS1216 RTC driver");
222MODULE_LICENSE("GPL");
223MODULE_VERSION(DRV_VERSION);
224MODULE_ALIAS("platform:rtc-ds1216");
225
226module_init(ds1216_rtc_init);
227module_exit(ds1216_rtc_exit);