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/gfp.h>
19#include <linux/delay.h>
20#include <linux/jiffies.h>
21#include <linux/rtc.h>
22#include <linux/platform_device.h>
23#include <linux/io.h>
24
25#define DRV_VERSION "0.4"
26
27#define RTC_SIZE 8
28
29#define RTC_CONTROL 0
30#define RTC_CENTURY 0
31#define RTC_SECONDS 1
32#define RTC_MINUTES 2
33#define RTC_HOURS 3
34#define RTC_DAY 4
35#define RTC_DATE 5
36#define RTC_MONTH 6
37#define RTC_YEAR 7
38
39#define RTC_CENTURY_MASK 0x3f
40#define RTC_SECONDS_MASK 0x7f
41#define RTC_DAY_MASK 0x07
42
43/* Bits in the Control/Century register */
44#define RTC_WRITE 0x80
45#define RTC_READ 0x40
46
47/* Bits in the Seconds register */
48#define RTC_STOP 0x80
49
50/* Bits in the Day register */
51#define RTC_BATT_FLAG 0x80
52
53struct rtc_plat_data {
54 struct rtc_device *rtc;
55 void __iomem *ioaddr_nvram;
56 void __iomem *ioaddr_rtc;
57 size_t size_nvram;
58 size_t size;
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 file *filp, struct kobject *kobj,
132 struct bin_attribute *bin_attr,
133 char *buf, loff_t pos, size_t size)
134{
135 struct device *dev = container_of(kobj, struct device, kobj);
136 struct platform_device *pdev = to_platform_device(dev);
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 file *filp, struct kobject *kobj,
147 struct bin_attribute *bin_attr,
148 char *buf, loff_t pos, size_t size)
149{
150 struct device *dev = container_of(kobj, struct device, kobj);
151 struct platform_device *pdev = to_platform_device(dev);
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;
167 void __iomem *ioaddr;
168 int ret = 0;
169
170 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
171 if (!res)
172 return -ENODEV;
173 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
174 if (!pdata)
175 return -ENOMEM;
176 pdata->size = resource_size(res);
177 if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
178 pdev->name))
179 return -EBUSY;
180 ioaddr = devm_ioremap(&pdev->dev, res->start, pdata->size);
181 if (!ioaddr)
182 return -ENOMEM;
183
184 pdata->ioaddr_nvram = ioaddr;
185 pdata->size_nvram = pdata->size - RTC_SIZE;
186 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
187
188 sysfs_bin_attr_init(&pdata->nvram_attr);
189 pdata->nvram_attr.attr.name = "nvram";
190 pdata->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
191 pdata->nvram_attr.read = ds1742_nvram_read;
192 pdata->nvram_attr.write = ds1742_nvram_write;
193 pdata->nvram_attr.size = pdata->size_nvram;
194
195 /* turn RTC on if it was not on */
196 ioaddr = pdata->ioaddr_rtc;
197 sec = readb(ioaddr + RTC_SECONDS);
198 if (sec & RTC_STOP) {
199 sec &= RTC_SECONDS_MASK;
200 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
201 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
202 writeb(sec, ioaddr + RTC_SECONDS);
203 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
204 }
205 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
206 dev_warn(&pdev->dev, "voltage-low detected.\n");
207
208 pdata->last_jiffies = jiffies;
209 platform_set_drvdata(pdev, pdata);
210 rtc = rtc_device_register(pdev->name, &pdev->dev,
211 &ds1742_rtc_ops, THIS_MODULE);
212 if (IS_ERR(rtc))
213 return PTR_ERR(rtc);
214 pdata->rtc = rtc;
215
216 ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
217 if (ret) {
218 dev_err(&pdev->dev, "creating nvram file in sysfs failed\n");
219 rtc_device_unregister(rtc);
220 }
221 return ret;
222}
223
224static int __devexit ds1742_rtc_remove(struct platform_device *pdev)
225{
226 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
227
228 sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
229 rtc_device_unregister(pdata->rtc);
230 return 0;
231}
232
233static struct platform_driver ds1742_rtc_driver = {
234 .probe = ds1742_rtc_probe,
235 .remove = __devexit_p(ds1742_rtc_remove),
236 .driver = {
237 .name = "rtc-ds1742",
238 .owner = THIS_MODULE,
239 },
240};
241
242static __init int ds1742_init(void)
243{
244 return platform_driver_register(&ds1742_rtc_driver);
245}
246
247static __exit void ds1742_exit(void)
248{
249 platform_driver_unregister(&ds1742_rtc_driver);
250}
251
252module_init(ds1742_init);
253module_exit(ds1742_exit);
254
255MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
256MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
257MODULE_LICENSE("GPL");
258MODULE_VERSION(DRV_VERSION);
259MODULE_ALIAS("platform:rtc-ds1742");