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 #include <linux/module.h>
25
26 #define DRV_VERSION "0.4"
27
28 #define RTC_SIZE 8
29
30 #define RTC_CONTROL 0
31 #define RTC_CENTURY 0
32 #define RTC_SECONDS 1
33 #define RTC_MINUTES 2
34 #define RTC_HOURS 3
35 #define RTC_DAY 4
36 #define RTC_DATE 5
37 #define RTC_MONTH 6
38 #define RTC_YEAR 7
39
40 #define RTC_CENTURY_MASK 0x3f
41 #define RTC_SECONDS_MASK 0x7f
42 #define RTC_DAY_MASK 0x07
43
44 /* Bits in the Control/Century register */
45 #define RTC_WRITE 0x80
46 #define RTC_READ 0x40
47
48 /* Bits in the Seconds register */
49 #define RTC_STOP 0x80
50
51 /* Bits in the Day register */
52 #define RTC_BATT_FLAG 0x80
53
54 struct rtc_plat_data {
55 struct rtc_device *rtc;
56 void __iomem *ioaddr_nvram;
57 void __iomem *ioaddr_rtc;
58 size_t size_nvram;
59 size_t size;
60 unsigned long last_jiffies;
61 struct bin_attribute nvram_attr;
62 };
63
ds1742_rtc_set_time(struct device * dev,struct rtc_time * tm)64 static int ds1742_rtc_set_time(struct device *dev, struct rtc_time *tm)
65 {
66 struct platform_device *pdev = to_platform_device(dev);
67 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
68 void __iomem *ioaddr = pdata->ioaddr_rtc;
69 u8 century;
70
71 century = bin2bcd((tm->tm_year + 1900) / 100);
72
73 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
74
75 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
76 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
77 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
78 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
79 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
80 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
81 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
82
83 /* RTC_CENTURY and RTC_CONTROL share same register */
84 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
85 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
86 return 0;
87 }
88
ds1742_rtc_read_time(struct device * dev,struct rtc_time * tm)89 static int ds1742_rtc_read_time(struct device *dev, struct rtc_time *tm)
90 {
91 struct platform_device *pdev = to_platform_device(dev);
92 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
93 void __iomem *ioaddr = pdata->ioaddr_rtc;
94 unsigned int year, month, day, hour, minute, second, week;
95 unsigned int century;
96
97 /* give enough time to update RTC in case of continuous read */
98 if (pdata->last_jiffies == jiffies)
99 msleep(1);
100 pdata->last_jiffies = jiffies;
101 writeb(RTC_READ, ioaddr + RTC_CONTROL);
102 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
103 minute = readb(ioaddr + RTC_MINUTES);
104 hour = readb(ioaddr + RTC_HOURS);
105 day = readb(ioaddr + RTC_DATE);
106 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
107 month = readb(ioaddr + RTC_MONTH);
108 year = readb(ioaddr + RTC_YEAR);
109 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
110 writeb(0, ioaddr + RTC_CONTROL);
111 tm->tm_sec = bcd2bin(second);
112 tm->tm_min = bcd2bin(minute);
113 tm->tm_hour = bcd2bin(hour);
114 tm->tm_mday = bcd2bin(day);
115 tm->tm_wday = bcd2bin(week);
116 tm->tm_mon = bcd2bin(month) - 1;
117 /* year is 1900 + tm->tm_year */
118 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
119
120 if (rtc_valid_tm(tm) < 0) {
121 dev_err(dev, "retrieved date/time is not valid.\n");
122 rtc_time_to_tm(0, tm);
123 }
124 return 0;
125 }
126
127 static const struct rtc_class_ops ds1742_rtc_ops = {
128 .read_time = ds1742_rtc_read_time,
129 .set_time = ds1742_rtc_set_time,
130 };
131
ds1742_nvram_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t pos,size_t size)132 static ssize_t ds1742_nvram_read(struct file *filp, struct kobject *kobj,
133 struct bin_attribute *bin_attr,
134 char *buf, loff_t pos, size_t size)
135 {
136 struct device *dev = container_of(kobj, struct device, kobj);
137 struct platform_device *pdev = to_platform_device(dev);
138 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
139 void __iomem *ioaddr = pdata->ioaddr_nvram;
140 ssize_t count;
141
142 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--)
143 *buf++ = readb(ioaddr + pos++);
144 return count;
145 }
146
ds1742_nvram_write(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t pos,size_t size)147 static ssize_t ds1742_nvram_write(struct file *filp, struct kobject *kobj,
148 struct bin_attribute *bin_attr,
149 char *buf, loff_t pos, size_t size)
150 {
151 struct device *dev = container_of(kobj, struct device, kobj);
152 struct platform_device *pdev = to_platform_device(dev);
153 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
154 void __iomem *ioaddr = pdata->ioaddr_nvram;
155 ssize_t count;
156
157 for (count = 0; size > 0 && pos < pdata->size_nvram; count++, size--)
158 writeb(*buf++, ioaddr + pos++);
159 return count;
160 }
161
ds1742_rtc_probe(struct platform_device * pdev)162 static int __devinit ds1742_rtc_probe(struct platform_device *pdev)
163 {
164 struct rtc_device *rtc;
165 struct resource *res;
166 unsigned int cen, sec;
167 struct rtc_plat_data *pdata;
168 void __iomem *ioaddr;
169 int ret = 0;
170
171 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
172 if (!res)
173 return -ENODEV;
174 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
175 if (!pdata)
176 return -ENOMEM;
177 pdata->size = resource_size(res);
178 if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
179 pdev->name))
180 return -EBUSY;
181 ioaddr = devm_ioremap(&pdev->dev, res->start, pdata->size);
182 if (!ioaddr)
183 return -ENOMEM;
184
185 pdata->ioaddr_nvram = ioaddr;
186 pdata->size_nvram = pdata->size - RTC_SIZE;
187 pdata->ioaddr_rtc = ioaddr + pdata->size_nvram;
188
189 sysfs_bin_attr_init(&pdata->nvram_attr);
190 pdata->nvram_attr.attr.name = "nvram";
191 pdata->nvram_attr.attr.mode = S_IRUGO | S_IWUSR;
192 pdata->nvram_attr.read = ds1742_nvram_read;
193 pdata->nvram_attr.write = ds1742_nvram_write;
194 pdata->nvram_attr.size = pdata->size_nvram;
195
196 /* turn RTC on if it was not on */
197 ioaddr = pdata->ioaddr_rtc;
198 sec = readb(ioaddr + RTC_SECONDS);
199 if (sec & RTC_STOP) {
200 sec &= RTC_SECONDS_MASK;
201 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
202 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
203 writeb(sec, ioaddr + RTC_SECONDS);
204 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
205 }
206 if (!(readb(ioaddr + RTC_DAY) & RTC_BATT_FLAG))
207 dev_warn(&pdev->dev, "voltage-low detected.\n");
208
209 pdata->last_jiffies = jiffies;
210 platform_set_drvdata(pdev, pdata);
211 rtc = rtc_device_register(pdev->name, &pdev->dev,
212 &ds1742_rtc_ops, THIS_MODULE);
213 if (IS_ERR(rtc))
214 return PTR_ERR(rtc);
215 pdata->rtc = rtc;
216
217 ret = sysfs_create_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
218 if (ret) {
219 dev_err(&pdev->dev, "creating nvram file in sysfs failed\n");
220 rtc_device_unregister(rtc);
221 }
222 return ret;
223 }
224
ds1742_rtc_remove(struct platform_device * pdev)225 static int __devexit ds1742_rtc_remove(struct platform_device *pdev)
226 {
227 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
228
229 sysfs_remove_bin_file(&pdev->dev.kobj, &pdata->nvram_attr);
230 rtc_device_unregister(pdata->rtc);
231 return 0;
232 }
233
234 static struct platform_driver ds1742_rtc_driver = {
235 .probe = ds1742_rtc_probe,
236 .remove = __devexit_p(ds1742_rtc_remove),
237 .driver = {
238 .name = "rtc-ds1742",
239 .owner = THIS_MODULE,
240 },
241 };
242
243 module_platform_driver(ds1742_rtc_driver);
244
245 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
246 MODULE_DESCRIPTION("Dallas DS1742 RTC driver");
247 MODULE_LICENSE("GPL");
248 MODULE_VERSION(DRV_VERSION);
249 MODULE_ALIAS("platform:rtc-ds1742");
250