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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 | #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); |
236 |
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