tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
52struct 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 struct bin_attribute nvram_attr;
61};
62
63static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
64{
65 struct platform_device *pdev = to_platform_device(dev);
66 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
67 void __iomem *ioaddr = pdata->ioaddr_rtc;
68 u8 century;
69
70 century = bin2bcd((tm->tm_year + 1900) / 100);
71
72 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
73
74 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
75 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
76 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
77 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
78 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
79 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
80 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
81
82 /* RTC_CENTURY and RTC_CONTROL share same register */
83 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
84 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
85 return 0;
86}
87
88static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
89{
90 struct platform_device *pdev = to_platform_device(dev);
91 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
92 void __iomem *ioaddr = pdata->ioaddr_rtc;
93 unsigned int year, month, day, hour, minute, second, week;
94 unsigned int century;
95
96 /* give enough time to update RTC in case of continuous read */
97 if (pdata->last_jiffies == jiffies)
98 msleep(1);
99 pdata->last_jiffies = jiffies;
100 writeb(RTC_READ, ioaddr + RTC_CONTROL);
101 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
102 minute = readb(ioaddr + RTC_MINUTES);
103 hour = readb(ioaddr + RTC_HOURS);
104 day = readb(ioaddr + RTC_DATE);
105 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
106 month = readb(ioaddr + RTC_MONTH);
107 year = readb(ioaddr + RTC_YEAR);
108 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
109 writeb(0, ioaddr + RTC_CONTROL);
110 tm->tm_sec = bcd2bin(second);
111 tm->tm_min = bcd2bin(minute);
112 tm->tm_hour = bcd2bin(hour);
113 tm->tm_mday = bcd2bin(day);
114 tm->tm_wday = bcd2bin(week);
115 tm->tm_mon = bcd2bin(month) - 1;
116 /* year is 1900 + tm->tm_year */
117 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
118
119 if (rtc_valid_tm(tm) < 0) {
120 dev_err(dev, "retrieved date/time is not valid.\n");
121 rtc_time_to_tm(0, tm);
122 }
123 return 0;
124}
125
126static const struct rtc_class_ops ds1742_rtc_ops = {
127 .read_time = ds1742_rtc_read_time,
128 .set_time = ds1742_rtc_set_time,
129};
130
131static ssize_t ds1742_nvram_read(struct kobject *kobj,
132 struct bin_attribute *bin_attr,
133 char *buf, loff_t pos, size_t size)
134{
135 struct platform_device *pdev =
136 to_platform_device(container_of(kobj, struct device, kobj));
137 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
138 void __iomem *ioaddr = pdata->ioaddr_nvram;
139 ssize_t count;
140
141 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--)
142 *buf++ = readb(ioaddr + pos++);
143 return count;
144}
145
146static ssize_t ds1742_nvram_write(struct kobject *kobj,
147 struct bin_attribute *bin_attr,
148 char *buf, loff_t pos, size_t size)
149{
150 struct platform_device *pdev =
151 to_platform_device(container_of(kobj, struct device, kobj));
152 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
153 void __iomem *ioaddr = pdata->ioaddr_nvram;
154 ssize_t count;
155
156 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--)
157 writeb(*buf++, ioaddr + pos++);
158 return count;
159}
160
161static int __devinit ds1742_rtc_probe(struct platform_device *pdev)
162{
163 struct rtc_device *rtc;
164 struct resource *res;
165 unsigned int cen, sec;
166 struct rtc_plat_data *pdata = NULL;
167 void __iomem *ioaddr = NULL;
168 int ret = 0;
169
170 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
171 if (!res)
172 return -ENODEV;
173 pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
174 if (!pdata)
175 return -ENOMEM;
176 pdata->size = res->end - res->start + 1;
177 if (!request_mem_region(res->start, pdata->size, pdev->name)) {
178 ret = -EBUSY;
179 goto out;
180 }
181 pdata->baseaddr = res->start;
182 ioaddr = ioremap(pdata->baseaddr, pdata->size);
183 if (!ioaddr) {
184 ret = -ENOMEM;
185 goto out;
186 }
187 pdata->ioaddr_nvram = ioaddr;
188 pdata->size_nvram = pdata->size - RTC_SIZE;
189 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
190
191 pdata->nvram_attr.attr.name = "nvram";
192 pdata->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
193 pdata->nvram_attr.read = ds1742_nvram_read;
194 pdata->nvram_attr.write = ds1742_nvram_write;
195 pdata->nvram_attr.size = pdata->size_nvram;
196
197 /* turn RTC on if it was not on */
198 ioaddr = pdata->ioaddr_rtc;
199 sec = readb(ioaddr + RTC_SECONDS);
200 if (sec & RTC_STOP) {
201 sec &= RTC_SECONDS_MASK;
202 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
203 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
204 writeb(sec, ioaddr + RTC_SECONDS);
205 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
206 }
207 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
208 dev_warn(&pdev->dev, "voltage-low detected.\n");
209
210 rtc = rtc_device_register(pdev->name, &pdev->dev,
211 &ds1742_rtc_ops, THIS_MODULE);
212 if (IS_ERR(rtc)) {
213 ret = PTR_ERR(rtc);
214 goto out;
215 }
216 pdata->rtc = rtc;
217 pdata->last_jiffies = jiffies;
218 platform_set_drvdata(pdev, pdata);
219
220 ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
221 if (ret) {
222 dev_err(&pdev->dev, "creating nvram file in sysfs failed\n");
223 goto out;
224 }
225
226 return 0;
227 out:
228 if (pdata->rtc)
229 rtc_device_unregister(pdata->rtc);
230 if (pdata->ioaddr_nvram)
231 iounmap(pdata->ioaddr_nvram);
232 if (pdata->baseaddr)
233 release_mem_region(pdata->baseaddr, pdata->size);
234 kfree(pdata);
235 return ret;
236}
237
238static int __devexit ds1742_rtc_remove(struct platform_device *pdev)
239{
240 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
241
242 sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
243 rtc_device_unregister(pdata->rtc);
244 iounmap(pdata->ioaddr_nvram);
245 release_mem_region(pdata->baseaddr, pdata->size);
246 kfree(pdata);
247 return 0;
248}
249
250static struct platform_driver ds1742_rtc_driver = {
251 .probe = ds1742_rtc_probe,
252 .remove = __devexit_p(ds1742_rtc_remove),
253 .driver = {
254 .name = "rtc-ds1742",
255 .owner = THIS_MODULE,
256 },
257};
258
259static __init int ds1742_init(void)
260{
261 return platform_driver_register(&ds1742_rtc_driver);
262}
263
264static __exit void ds1742_exit(void)
265{
266 platform_driver_unregister(&ds1742_rtc_driver);
267}
268
269module_init(ds1742_init);
270module_exit(ds1742_exit);
271
272MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
273MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
274MODULE_LICENSE("GPL");
275MODULE_VERSION(DRV_VERSION);
276MODULE_ALIAS("platform:rtc-ds1742");