blob: 0b21975599400c809098b905c26a5d6dd802002f [file] [log] [blame]
Thomas Bogendoerferd1dbd82e2008-10-14 17:17:32 +02001/*
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>
Geert Uytterhoevend7a61192008-10-16 09:28:47 +020021#include <linux/io.h>
Thomas Bogendoerferd1dbd82e2008-10-14 17:17:32 +020022
23#define DRV_VERSION "1.0"
24
25struct 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
40struct 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
48static 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
90static 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
138static const struct rtc_class_ops m48t35_ops = {
139 .read_time = m48t35_read_time,
140 .set_time = m48t35_set_time,
141};
142
143static 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
185out:
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
196static 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
209static 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
218static int __init m48t35_init(void)
219{
220 return platform_driver_register(&m48t35_platform_driver);
221}
222
223static void __exit m48t35_exit(void)
224{
225 platform_driver_unregister(&m48t35_platform_driver);
226}
227
228MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
229MODULE_DESCRIPTION("M48T35 RTC driver");
230MODULE_LICENSE("GPL");
231MODULE_VERSION(DRV_VERSION);
232MODULE_ALIAS("platform:rtc-m48t35");
233
234module_init(m48t35_init);
235module_exit(m48t35_exit);