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