1 /*
2 * An rtc driver for the Dallas DS1742
3 *
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Copyright (C) 2006 Torsten Ertbjerg Rasmussen <tr@newtec.dk>
11 * - nvram size determined from resource
12 * - this ds1742 driver now supports ds1743.
13 */
14
15 #include <linux/bcd.h>
16 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/delay.h>
19 #include <linux/jiffies.h>
20 #include <linux/rtc.h>
21 #include <linux/platform_device.h>
22 #include <linux/io.h>
23
24 #define DRV_VERSION "0.3"
25
26 #define RTC_SIZE 8
27
28 #define RTC_CONTROL 0
29 #define RTC_CENTURY 0
30 #define RTC_SECONDS 1
31 #define RTC_MINUTES 2
32 #define RTC_HOURS 3
33 #define RTC_DAY 4
34 #define RTC_DATE 5
35 #define RTC_MONTH 6
36 #define RTC_YEAR 7
37
38 #define RTC_CENTURY_MASK 0x3f
39 #define RTC_SECONDS_MASK 0x7f
40 #define RTC_DAY_MASK 0x07
41
42 /* Bits in the Control/Century register */
43 #define RTC_WRITE 0x80
44 #define RTC_READ 0x40
45
46 /* Bits in the Seconds register */
47 #define RTC_STOP 0x80
48
49 /* Bits in the Day register */
50 #define RTC_BATT_FLAG 0x80
51
52 struct rtc_plat_data {
53 struct rtc_device *rtc;
54 void __iomem *ioaddr_nvram;
55 void __iomem *ioaddr_rtc;
56 size_t size_nvram;
57 size_t size;
58 resource_size_t baseaddr;
59 unsigned long last_jiffies;
60 };
61
62 static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
63 {
64 struct platform_device *pdev = to_platform_device(dev);
65 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
66 void __iomem *ioaddr = pdata->ioaddr_rtc;
67 u8 century;
68
69 century = BIN2BCD((tm->tm_year + 1900) / 100);
70
71 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
72
73 writeb(BIN2BCD(tm->tm_year % 100), ioaddr + RTC_YEAR);
74 writeb(BIN2BCD(tm->tm_mon + 1), ioaddr + RTC_MONTH);
75 writeb(BIN2BCD(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
76 writeb(BIN2BCD(tm->tm_mday), ioaddr + RTC_DATE);
77 writeb(BIN2BCD(tm->tm_hour), ioaddr + RTC_HOURS);
78 writeb(BIN2BCD(tm->tm_min), ioaddr + RTC_MINUTES);
79 writeb(BIN2BCD(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
80
81 /* RTC_CENTURY and RTC_CONTROL share same register */
82 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
83 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
84 return 0;
85 }
86
87 static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
88 {
89 struct platform_device *pdev = to_platform_device(dev);
90 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
91 void __iomem *ioaddr = pdata->ioaddr_rtc;
92 unsigned int year, month, day, hour, minute, second, week;
93 unsigned int century;
94
95 /* give enough time to update RTC in case of continuous read */
96 if (pdata->last_jiffies == jiffies)
97 msleep(1);
98 pdata->last_jiffies = jiffies;
99 writeb(RTC_READ, ioaddr + RTC_CONTROL);
100 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
101 minute = readb(ioaddr + RTC_MINUTES);
102 hour = readb(ioaddr + RTC_HOURS);
103 day = readb(ioaddr + RTC_DATE);
104 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
105 month = readb(ioaddr + RTC_MONTH);
106 year = readb(ioaddr + RTC_YEAR);
107 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
108 writeb(0, ioaddr + RTC_CONTROL);
109 tm->tm_sec = BCD2BIN(second);
110 tm->tm_min = BCD2BIN(minute);
111 tm->tm_hour = BCD2BIN(hour);
112 tm->tm_mday = BCD2BIN(day);
113 tm->tm_wday = BCD2BIN(week);
114 tm->tm_mon = BCD2BIN(month) - 1;
115 /* year is 1900 + tm->tm_year */
116 tm->tm_year = BCD2BIN(year) + BCD2BIN(century) * 100 - 1900;
117
118 if (rtc_valid_tm(tm) < 0) {
119 dev_err(dev, "retrieved date/time is not valid.\n");
120 rtc_time_to_tm(0, tm);
121 }
122 return 0;
123 }
124
125 static const struct rtc_class_ops ds1742_rtc_ops = {
126 .read_time = ds1742_rtc_read_time,
127 .set_time = ds1742_rtc_set_time,
128 };
129
130 static ssize_t ds1742_nvram_read(struct kobject *kobj,
131 struct bin_attribute *bin_attr,
132 char *buf, loff_t pos, size_t size)
133 {
134 struct platform_device *pdev =
135 to_platform_device(container_of(kobj, struct device, kobj));
136 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
137 void __iomem *ioaddr = pdata->ioaddr_nvram;
138 ssize_t count;
139
140 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--)
141 *buf++ = readb(ioaddr + pos++);
142 return count;
143 }
144
145 static ssize_t ds1742_nvram_write(struct kobject *kobj,
146 struct bin_attribute *bin_attr,
147 char *buf, loff_t pos, size_t size)
148 {
149 struct platform_device *pdev =
150 to_platform_device(container_of(kobj, struct device, kobj));
151 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
152 void __iomem *ioaddr = pdata->ioaddr_nvram;
153 ssize_t count;
154
155 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--)
156 writeb(*buf++, ioaddr + pos++);
157 return count;
158 }
159
160 static struct bin_attribute ds1742_nvram_attr = {
161 .attr = {
162 .name = "nvram",
163 .mode = S_IRUGO | S_IWUSR,
164 },
165 .read = ds1742_nvram_read,
166 .write = ds1742_nvram_write,
167 /* REVISIT: size in sysfs won't match actual size... if it's
168 * not a constant, each RTC should have its own attribute.
169 */
170 };
171
172 static int __devinit ds1742_rtc_probe(struct platform_device *pdev)
173 {
174 struct rtc_device *rtc;
175 struct resource *res;
176 unsigned int cen, sec;
177 struct rtc_plat_data *pdata = NULL;
178 void __iomem *ioaddr = NULL;
179 int ret = 0;
180
181 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
182 if (!res)
183 return -ENODEV;
184 pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
185 if (!pdata)
186 return -ENOMEM;
187 pdata->size = res->end - res->start + 1;
188 if (!request_mem_region(res->start, pdata->size, pdev->name)) {
189 ret = -EBUSY;
190 goto out;
191 }
192 pdata->baseaddr = res->start;
193 ioaddr = ioremap(pdata->baseaddr, pdata->size);
194 if (!ioaddr) {
195 ret = -ENOMEM;
196 goto out;
197 }
198 pdata->ioaddr_nvram = ioaddr;
199 pdata->size_nvram = pdata->size - RTC_SIZE;
200 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
201
202 /* turn RTC on if it was not on */
203 ioaddr = pdata->ioaddr_rtc;
204 sec = readb(ioaddr + RTC_SECONDS);
205 if (sec & RTC_STOP) {
206 sec &= RTC_SECONDS_MASK;
207 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
208 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
209 writeb(sec, ioaddr + RTC_SECONDS);
210 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
211 }
212 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
213 dev_warn(&pdev->dev, "voltage-low detected.\n");
214
215 rtc = rtc_device_register(pdev->name, &pdev->dev,
216 &ds1742_rtc_ops, THIS_MODULE);
217 if (IS_ERR(rtc)) {
218 ret = PTR_ERR(rtc);
219 goto out;
220 }
221 pdata->rtc = rtc;
222 pdata->last_jiffies = jiffies;
223 platform_set_drvdata(pdev, pdata);
224 ds1742_nvram_attr.size = max(ds1742_nvram_attr.size,
225 pdata->size_nvram);
226 ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);
227 if (ret)
228 goto out;
229 return 0;
230 out:
231 if (pdata->rtc)
232 rtc_device_unregister(pdata->rtc);
233 if (pdata->ioaddr_nvram)
234 iounmap(pdata->ioaddr_nvram);
235 if (pdata->baseaddr)
236 release_mem_region(pdata->baseaddr, pdata->size);
237 kfree(pdata);
238 return ret;
239 }
240
241 static int __devexit ds1742_rtc_remove(struct platform_device *pdev)
242 {
243 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
244
245 sysfs_remove_bin_file(&pdev->dev.kobj, &ds1742_nvram_attr);
246 rtc_device_unregister(pdata->rtc);
247 iounmap(pdata->ioaddr_nvram);
248 release_mem_region(pdata->baseaddr, pdata->size);
249 kfree(pdata);
250 return 0;
251 }
252
253 static struct platform_driver ds1742_rtc_driver = {
254 .probe = ds1742_rtc_probe,
255 .remove = __devexit_p(ds1742_rtc_remove),
256 .driver = {
257 .name = "rtc-ds1742",
258 .owner = THIS_MODULE,
259 },
260 };
261
262 static __init int ds1742_init(void)
263 {
264 return platform_driver_register(&ds1742_rtc_driver);
265 }
266
267 static __exit void ds1742_exit(void)
268 {
269 platform_driver_unregister(&ds1742_rtc_driver);
270 }
271
272 module_init(ds1742_init);
273 module_exit(ds1742_exit);
274
275 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
276 MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
277 MODULE_LICENSE("GPL");
278 MODULE_VERSION(DRV_VERSION);
279 MODULE_ALIAS("platform:rtc-ds1742");
280
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