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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 | struct bin_attribute nvram_attr; |
61 | }; |
62 | |
63 | static 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 | |
88 | static 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 | |
126 | static const struct rtc_class_ops ds1742_rtc_ops = { |
127 | .read_time = ds1742_rtc_read_time, |
128 | .set_time = ds1742_rtc_set_time, |
129 | }; |
130 | |
131 | static 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 | |
146 | static 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 | |
161 | static 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 | |
238 | static 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 | |
250 | static 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 | |
259 | static __init int ds1742_init(void) |
260 | { |
261 | return platform_driver_register(&ds1742_rtc_driver); |
262 | } |
263 | |
264 | static __exit void ds1742_exit(void) |
265 | { |
266 | platform_driver_unregister(&ds1742_rtc_driver); |
267 | } |
268 | |
269 | module_init(ds1742_init); |
270 | module_exit(ds1742_exit); |
271 | |
272 | MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); |
273 | MODULE_DESCRIPTION("Dallas DS1742 RTC driver"); |
274 | MODULE_LICENSE("GPL"); |
275 | MODULE_VERSION(DRV_VERSION); |
276 | MODULE_ALIAS("platform:rtc-ds1742"); |
277 |
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