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1 | /* |
2 | * Dallas DS1216 RTC driver |
3 | * |
4 | * Copyright (c) 2007 Thomas Bogendoerfer |
5 | * |
6 | */ |
7 | |
8 | #include <linux/module.h> |
9 | #include <linux/rtc.h> |
10 | #include <linux/platform_device.h> |
11 | #include <linux/bcd.h> |
12 | #include <linux/slab.h> |
13 | |
14 | #define DRV_VERSION "0.2" |
15 | |
16 | struct ds1216_regs { |
17 | u8 tsec; |
18 | u8 sec; |
19 | u8 min; |
20 | u8 hour; |
21 | u8 wday; |
22 | u8 mday; |
23 | u8 month; |
24 | u8 year; |
25 | }; |
26 | |
27 | #define DS1216_HOUR_1224 (1 << 7) |
28 | #define DS1216_HOUR_AMPM (1 << 5) |
29 | |
30 | struct ds1216_priv { |
31 | struct rtc_device *rtc; |
32 | void __iomem *ioaddr; |
33 | size_t size; |
34 | unsigned long baseaddr; |
35 | }; |
36 | |
37 | static const u8 magic[] = { |
38 | 0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c |
39 | }; |
40 | |
41 | /* |
42 | * Read the 64 bit we'd like to have - It a series |
43 | * of 64 bits showing up in the LSB of the base register. |
44 | * |
45 | */ |
46 | static void ds1216_read(u8 __iomem *ioaddr, u8 *buf) |
47 | { |
48 | unsigned char c; |
49 | int i, j; |
50 | |
51 | for (i = 0; i < 8; i++) { |
52 | c = 0; |
53 | for (j = 0; j < 8; j++) |
54 | c |= (readb(ioaddr) & 0x1) << j; |
55 | buf[i] = c; |
56 | } |
57 | } |
58 | |
59 | static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf) |
60 | { |
61 | unsigned char c; |
62 | int i, j; |
63 | |
64 | for (i = 0; i < 8; i++) { |
65 | c = buf[i]; |
66 | for (j = 0; j < 8; j++) { |
67 | writeb(c, ioaddr); |
68 | c = c >> 1; |
69 | } |
70 | } |
71 | } |
72 | |
73 | static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr) |
74 | { |
75 | /* Reset magic pointer */ |
76 | readb(ioaddr); |
77 | /* Write 64 bit magic to DS1216 */ |
78 | ds1216_write(ioaddr, magic); |
79 | } |
80 | |
81 | static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm) |
82 | { |
83 | struct platform_device *pdev = to_platform_device(dev); |
84 | struct ds1216_priv *priv = platform_get_drvdata(pdev); |
85 | struct ds1216_regs regs; |
86 | |
87 | ds1216_switch_ds_to_clock(priv->ioaddr); |
88 | ds1216_read(priv->ioaddr, (u8 *)®s); |
89 | |
90 | tm->tm_sec = bcd2bin(regs.sec); |
91 | tm->tm_min = bcd2bin(regs.min); |
92 | if (regs.hour & DS1216_HOUR_1224) { |
93 | /* AM/PM mode */ |
94 | tm->tm_hour = bcd2bin(regs.hour & 0x1f); |
95 | if (regs.hour & DS1216_HOUR_AMPM) |
96 | tm->tm_hour += 12; |
97 | } else |
98 | tm->tm_hour = bcd2bin(regs.hour & 0x3f); |
99 | tm->tm_wday = (regs.wday & 7) - 1; |
100 | tm->tm_mday = bcd2bin(regs.mday & 0x3f); |
101 | tm->tm_mon = bcd2bin(regs.month & 0x1f); |
102 | tm->tm_year = bcd2bin(regs.year); |
103 | if (tm->tm_year < 70) |
104 | tm->tm_year += 100; |
105 | |
106 | return rtc_valid_tm(tm); |
107 | } |
108 | |
109 | static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm) |
110 | { |
111 | struct platform_device *pdev = to_platform_device(dev); |
112 | struct ds1216_priv *priv = platform_get_drvdata(pdev); |
113 | struct ds1216_regs regs; |
114 | |
115 | ds1216_switch_ds_to_clock(priv->ioaddr); |
116 | ds1216_read(priv->ioaddr, (u8 *)®s); |
117 | |
118 | regs.tsec = 0; /* clear 0.1 and 0.01 seconds */ |
119 | regs.sec = bin2bcd(tm->tm_sec); |
120 | regs.min = bin2bcd(tm->tm_min); |
121 | regs.hour &= DS1216_HOUR_1224; |
122 | if (regs.hour && tm->tm_hour > 12) { |
123 | regs.hour |= DS1216_HOUR_AMPM; |
124 | tm->tm_hour -= 12; |
125 | } |
126 | regs.hour |= bin2bcd(tm->tm_hour); |
127 | regs.wday &= ~7; |
128 | regs.wday |= tm->tm_wday; |
129 | regs.mday = bin2bcd(tm->tm_mday); |
130 | regs.month = bin2bcd(tm->tm_mon); |
131 | regs.year = bin2bcd(tm->tm_year % 100); |
132 | |
133 | ds1216_switch_ds_to_clock(priv->ioaddr); |
134 | ds1216_write(priv->ioaddr, (u8 *)®s); |
135 | return 0; |
136 | } |
137 | |
138 | static const struct rtc_class_ops ds1216_rtc_ops = { |
139 | .read_time = ds1216_rtc_read_time, |
140 | .set_time = ds1216_rtc_set_time, |
141 | }; |
142 | |
143 | static int __init ds1216_rtc_probe(struct platform_device *pdev) |
144 | { |
145 | struct resource *res; |
146 | struct ds1216_priv *priv; |
147 | int ret = 0; |
148 | u8 dummy[8]; |
149 | |
150 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
151 | if (!res) |
152 | return -ENODEV; |
153 | priv = kzalloc(sizeof *priv, GFP_KERNEL); |
154 | if (!priv) |
155 | return -ENOMEM; |
156 | |
157 | platform_set_drvdata(pdev, priv); |
158 | |
159 | priv->size = resource_size(res); |
160 | if (!request_mem_region(res->start, priv->size, pdev->name)) { |
161 | ret = -EBUSY; |
162 | goto out; |
163 | } |
164 | priv->baseaddr = res->start; |
165 | priv->ioaddr = ioremap(priv->baseaddr, priv->size); |
166 | if (!priv->ioaddr) { |
167 | ret = -ENOMEM; |
168 | goto out; |
169 | } |
170 | priv->rtc = rtc_device_register("ds1216", &pdev->dev, |
171 | &ds1216_rtc_ops, THIS_MODULE); |
172 | if (IS_ERR(priv->rtc)) { |
173 | ret = PTR_ERR(priv->rtc); |
174 | goto out; |
175 | } |
176 | |
177 | /* dummy read to get clock into a known state */ |
178 | ds1216_read(priv->ioaddr, dummy); |
179 | return 0; |
180 | |
181 | out: |
182 | if (priv->ioaddr) |
183 | iounmap(priv->ioaddr); |
184 | if (priv->baseaddr) |
185 | release_mem_region(priv->baseaddr, priv->size); |
186 | kfree(priv); |
187 | return ret; |
188 | } |
189 | |
190 | static int __exit ds1216_rtc_remove(struct platform_device *pdev) |
191 | { |
192 | struct ds1216_priv *priv = platform_get_drvdata(pdev); |
193 | |
194 | rtc_device_unregister(priv->rtc); |
195 | iounmap(priv->ioaddr); |
196 | release_mem_region(priv->baseaddr, priv->size); |
197 | kfree(priv); |
198 | return 0; |
199 | } |
200 | |
201 | static struct platform_driver ds1216_rtc_platform_driver = { |
202 | .driver = { |
203 | .name = "rtc-ds1216", |
204 | .owner = THIS_MODULE, |
205 | }, |
206 | .remove = __exit_p(ds1216_rtc_remove), |
207 | }; |
208 | |
209 | static int __init ds1216_rtc_init(void) |
210 | { |
211 | return platform_driver_probe(&ds1216_rtc_platform_driver, ds1216_rtc_probe); |
212 | } |
213 | |
214 | static void __exit ds1216_rtc_exit(void) |
215 | { |
216 | platform_driver_unregister(&ds1216_rtc_platform_driver); |
217 | } |
218 | |
219 | MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); |
220 | MODULE_DESCRIPTION("DS1216 RTC driver"); |
221 | MODULE_LICENSE("GPL"); |
222 | MODULE_VERSION(DRV_VERSION); |
223 | MODULE_ALIAS("platform:rtc-ds1216"); |
224 | |
225 | module_init(ds1216_rtc_init); |
226 | module_exit(ds1216_rtc_exit); |
227 |
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