Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi...
[linux-2.6] / drivers / rtc / rtc-m48t35.c
1 /*
2  * Driver for the SGS-Thomson M48T35 Timekeeper RAM chip
3  *
4  * Copyright (C) 2000 Silicon Graphics, Inc.
5  * Written by Ulf Carlsson (ulfc@engr.sgi.com)
6  *
7  * Copyright (C) 2008 Thomas Bogendoerfer
8  *
9  * Based on code written by Paul Gortmaker.
10  *
11  * This program is free software; you can redistribute it and/or modify it
12  * under the terms of the GNU General Public License as published by the
13  * Free Software Foundation; either version 2 of the License, or (at your
14  * option) any later version.
15  */
16
17 #include <linux/module.h>
18 #include <linux/rtc.h>
19 #include <linux/platform_device.h>
20 #include <linux/bcd.h>
21 #include <linux/io.h>
22
23 #define DRV_VERSION             "1.0"
24
25 struct m48t35_rtc {
26         u8      pad[0x7ff8];    /* starts at 0x7ff8 */
27         u8      control;
28         u8      sec;
29         u8      min;
30         u8      hour;
31         u8      day;
32         u8      date;
33         u8      month;
34         u8      year;
35 };
36
37 #define M48T35_RTC_SET          0x80
38 #define M48T35_RTC_READ         0x40
39
40 struct m48t35_priv {
41         struct rtc_device *rtc;
42         struct m48t35_rtc __iomem *reg;
43         size_t size;
44         unsigned long baseaddr;
45         spinlock_t lock;
46 };
47
48 static int m48t35_read_time(struct device *dev, struct rtc_time *tm)
49 {
50         struct m48t35_priv *priv = dev_get_drvdata(dev);
51         u8 control;
52
53         /*
54          * Only the values that we read from the RTC are set. We leave
55          * tm_wday, tm_yday and tm_isdst untouched. Even though the
56          * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
57          * by the RTC when initially set to a non-zero value.
58          */
59         spin_lock_irq(&priv->lock);
60         control = readb(&priv->reg->control);
61         writeb(control | M48T35_RTC_READ, &priv->reg->control);
62         tm->tm_sec = readb(&priv->reg->sec);
63         tm->tm_min = readb(&priv->reg->min);
64         tm->tm_hour = readb(&priv->reg->hour);
65         tm->tm_mday = readb(&priv->reg->date);
66         tm->tm_mon = readb(&priv->reg->month);
67         tm->tm_year = readb(&priv->reg->year);
68         writeb(control, &priv->reg->control);
69         spin_unlock_irq(&priv->lock);
70
71         tm->tm_sec = bcd2bin(tm->tm_sec);
72         tm->tm_min = bcd2bin(tm->tm_min);
73         tm->tm_hour = bcd2bin(tm->tm_hour);
74         tm->tm_mday = bcd2bin(tm->tm_mday);
75         tm->tm_mon = bcd2bin(tm->tm_mon);
76         tm->tm_year = bcd2bin(tm->tm_year);
77
78         /*
79          * Account for differences between how the RTC uses the values
80          * and how they are defined in a struct rtc_time;
81          */
82         tm->tm_year += 70;
83         if (tm->tm_year <= 69)
84                 tm->tm_year += 100;
85
86         tm->tm_mon--;
87         return rtc_valid_tm(tm);
88 }
89
90 static int m48t35_set_time(struct device *dev, struct rtc_time *tm)
91 {
92         struct m48t35_priv *priv = dev_get_drvdata(dev);
93         unsigned char mon, day, hrs, min, sec;
94         unsigned int yrs;
95         u8 control;
96
97         yrs = tm->tm_year + 1900;
98         mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
99         day = tm->tm_mday;
100         hrs = tm->tm_hour;
101         min = tm->tm_min;
102         sec = tm->tm_sec;
103
104         if (yrs < 1970)
105                 return -EINVAL;
106
107         yrs -= 1970;
108         if (yrs > 255)    /* They are unsigned */
109                 return -EINVAL;
110
111         if (yrs > 169)
112                 return -EINVAL;
113
114         if (yrs >= 100)
115                 yrs -= 100;
116
117         sec = bin2bcd(sec);
118         min = bin2bcd(min);
119         hrs = bin2bcd(hrs);
120         day = bin2bcd(day);
121         mon = bin2bcd(mon);
122         yrs = bin2bcd(yrs);
123
124         spin_lock_irq(&priv->lock);
125         control = readb(&priv->reg->control);
126         writeb(control | M48T35_RTC_SET, &priv->reg->control);
127         writeb(yrs, &priv->reg->year);
128         writeb(mon, &priv->reg->month);
129         writeb(day, &priv->reg->date);
130         writeb(hrs, &priv->reg->hour);
131         writeb(min, &priv->reg->min);
132         writeb(sec, &priv->reg->sec);
133         writeb(control, &priv->reg->control);
134         spin_unlock_irq(&priv->lock);
135         return 0;
136 }
137
138 static const struct rtc_class_ops m48t35_ops = {
139         .read_time      = m48t35_read_time,
140         .set_time       = m48t35_set_time,
141 };
142
143 static int __devinit m48t35_probe(struct platform_device *pdev)
144 {
145         struct rtc_device *rtc;
146         struct resource *res;
147         struct m48t35_priv *priv;
148         int ret = 0;
149
150         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
151         if (!res)
152                 return -ENODEV;
153         priv = kzalloc(sizeof(struct m48t35_priv), GFP_KERNEL);
154         if (!priv)
155                 return -ENOMEM;
156
157         priv->size = res->end - res->start + 1;
158         /*
159          * kludge: remove the #ifndef after ioc3 resource
160          * conflicts are resolved
161          */
162 #ifndef CONFIG_SGI_IP27
163         if (!request_mem_region(res->start, priv->size, pdev->name)) {
164                 ret = -EBUSY;
165                 goto out;
166         }
167 #endif
168         priv->baseaddr = res->start;
169         priv->reg = ioremap(priv->baseaddr, priv->size);
170         if (!priv->reg) {
171                 ret = -ENOMEM;
172                 goto out;
173         }
174         spin_lock_init(&priv->lock);
175         rtc = rtc_device_register("m48t35", &pdev->dev,
176                                   &m48t35_ops, THIS_MODULE);
177         if (IS_ERR(rtc)) {
178                 ret = PTR_ERR(rtc);
179                 goto out;
180         }
181         priv->rtc = rtc;
182         platform_set_drvdata(pdev, priv);
183         return 0;
184
185 out:
186         if (priv->rtc)
187                 rtc_device_unregister(priv->rtc);
188         if (priv->reg)
189                 iounmap(priv->reg);
190         if (priv->baseaddr)
191                 release_mem_region(priv->baseaddr, priv->size);
192         kfree(priv);
193         return ret;
194 }
195
196 static int __devexit m48t35_remove(struct platform_device *pdev)
197 {
198         struct m48t35_priv *priv = platform_get_drvdata(pdev);
199
200         rtc_device_unregister(priv->rtc);
201         iounmap(priv->reg);
202 #ifndef CONFIG_SGI_IP27
203         release_mem_region(priv->baseaddr, priv->size);
204 #endif
205         kfree(priv);
206         return 0;
207 }
208
209 static struct platform_driver m48t35_platform_driver = {
210         .driver         = {
211                 .name   = "rtc-m48t35",
212                 .owner  = THIS_MODULE,
213         },
214         .probe          = m48t35_probe,
215         .remove         = __devexit_p(m48t35_remove),
216 };
217
218 static int __init m48t35_init(void)
219 {
220         return platform_driver_register(&m48t35_platform_driver);
221 }
222
223 static void __exit m48t35_exit(void)
224 {
225         platform_driver_unregister(&m48t35_platform_driver);
226 }
227
228 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
229 MODULE_DESCRIPTION("M48T35 RTC driver");
230 MODULE_LICENSE("GPL");
231 MODULE_VERSION(DRV_VERSION);
232 MODULE_ALIAS("platform:rtc-m48t35");
233
234 module_init(m48t35_init);
235 module_exit(m48t35_exit);