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537739de TB |
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> | |
5a0e3ad6 | 12 | #include <linux/slab.h> |
537739de | 13 | |
97a1f953 | 14 | #define DRV_VERSION "0.2" |
537739de TB |
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; | |
537739de TB |
33 | }; |
34 | ||
35 | static const u8 magic[] = { | |
36 | 0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c | |
37 | }; | |
38 | ||
39 | /* | |
40 | * Read the 64 bit we'd like to have - It a series | |
41 | * of 64 bits showing up in the LSB of the base register. | |
42 | * | |
43 | */ | |
44 | static void ds1216_read(u8 __iomem *ioaddr, u8 *buf) | |
45 | { | |
46 | unsigned char c; | |
47 | int i, j; | |
48 | ||
49 | for (i = 0; i < 8; i++) { | |
50 | c = 0; | |
51 | for (j = 0; j < 8; j++) | |
52 | c |= (readb(ioaddr) & 0x1) << j; | |
53 | buf[i] = c; | |
54 | } | |
55 | } | |
56 | ||
57 | static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf) | |
58 | { | |
59 | unsigned char c; | |
60 | int i, j; | |
61 | ||
62 | for (i = 0; i < 8; i++) { | |
63 | c = buf[i]; | |
64 | for (j = 0; j < 8; j++) { | |
65 | writeb(c, ioaddr); | |
66 | c = c >> 1; | |
67 | } | |
68 | } | |
69 | } | |
70 | ||
71 | static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr) | |
72 | { | |
73 | /* Reset magic pointer */ | |
74 | readb(ioaddr); | |
75 | /* Write 64 bit magic to DS1216 */ | |
76 | ds1216_write(ioaddr, magic); | |
77 | } | |
78 | ||
79 | static int ds1216_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
80 | { | |
81 | struct platform_device *pdev = to_platform_device(dev); | |
82 | struct ds1216_priv *priv = platform_get_drvdata(pdev); | |
83 | struct ds1216_regs regs; | |
84 | ||
85 | ds1216_switch_ds_to_clock(priv->ioaddr); | |
86 | ds1216_read(priv->ioaddr, (u8 *)®s); | |
87 | ||
fe20ba70 AB |
88 | tm->tm_sec = bcd2bin(regs.sec); |
89 | tm->tm_min = bcd2bin(regs.min); | |
537739de TB |
90 | if (regs.hour & DS1216_HOUR_1224) { |
91 | /* AM/PM mode */ | |
fe20ba70 | 92 | tm->tm_hour = bcd2bin(regs.hour & 0x1f); |
537739de TB |
93 | if (regs.hour & DS1216_HOUR_AMPM) |
94 | tm->tm_hour += 12; | |
95 | } else | |
fe20ba70 | 96 | tm->tm_hour = bcd2bin(regs.hour & 0x3f); |
537739de | 97 | tm->tm_wday = (regs.wday & 7) - 1; |
fe20ba70 AB |
98 | tm->tm_mday = bcd2bin(regs.mday & 0x3f); |
99 | tm->tm_mon = bcd2bin(regs.month & 0x1f); | |
100 | tm->tm_year = bcd2bin(regs.year); | |
537739de TB |
101 | if (tm->tm_year < 70) |
102 | tm->tm_year += 100; | |
97a1f953 AZ |
103 | |
104 | return rtc_valid_tm(tm); | |
537739de TB |
105 | } |
106 | ||
107 | static int ds1216_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
108 | { | |
109 | struct platform_device *pdev = to_platform_device(dev); | |
110 | struct ds1216_priv *priv = platform_get_drvdata(pdev); | |
111 | struct ds1216_regs regs; | |
112 | ||
113 | ds1216_switch_ds_to_clock(priv->ioaddr); | |
114 | ds1216_read(priv->ioaddr, (u8 *)®s); | |
115 | ||
116 | regs.tsec = 0; /* clear 0.1 and 0.01 seconds */ | |
fe20ba70 AB |
117 | regs.sec = bin2bcd(tm->tm_sec); |
118 | regs.min = bin2bcd(tm->tm_min); | |
537739de TB |
119 | regs.hour &= DS1216_HOUR_1224; |
120 | if (regs.hour && tm->tm_hour > 12) { | |
121 | regs.hour |= DS1216_HOUR_AMPM; | |
122 | tm->tm_hour -= 12; | |
123 | } | |
fe20ba70 | 124 | regs.hour |= bin2bcd(tm->tm_hour); |
537739de TB |
125 | regs.wday &= ~7; |
126 | regs.wday |= tm->tm_wday; | |
fe20ba70 AB |
127 | regs.mday = bin2bcd(tm->tm_mday); |
128 | regs.month = bin2bcd(tm->tm_mon); | |
129 | regs.year = bin2bcd(tm->tm_year % 100); | |
537739de TB |
130 | |
131 | ds1216_switch_ds_to_clock(priv->ioaddr); | |
132 | ds1216_write(priv->ioaddr, (u8 *)®s); | |
133 | return 0; | |
134 | } | |
135 | ||
136 | static const struct rtc_class_ops ds1216_rtc_ops = { | |
137 | .read_time = ds1216_rtc_read_time, | |
138 | .set_time = ds1216_rtc_set_time, | |
139 | }; | |
140 | ||
97a1f953 | 141 | static int __init ds1216_rtc_probe(struct platform_device *pdev) |
537739de | 142 | { |
537739de TB |
143 | struct resource *res; |
144 | struct ds1216_priv *priv; | |
537739de TB |
145 | u8 dummy[8]; |
146 | ||
147 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
148 | if (!res) | |
149 | return -ENODEV; | |
15c1567a | 150 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
537739de TB |
151 | if (!priv) |
152 | return -ENOMEM; | |
97a1f953 AZ |
153 | |
154 | platform_set_drvdata(pdev, priv); | |
155 | ||
15c1567a JH |
156 | priv->ioaddr = devm_ioremap_resource(&pdev->dev, res); |
157 | if (IS_ERR(priv->ioaddr)) | |
158 | return PTR_ERR(priv->ioaddr); | |
159 | ||
160 | priv->rtc = devm_rtc_device_register(&pdev->dev, "ds1216", | |
161 | &ds1216_rtc_ops, THIS_MODULE); | |
162 | if (IS_ERR(priv->rtc)) | |
163 | return PTR_ERR(priv->rtc); | |
537739de TB |
164 | |
165 | /* dummy read to get clock into a known state */ | |
166 | ds1216_read(priv->ioaddr, dummy); | |
167 | return 0; | |
537739de TB |
168 | } |
169 | ||
537739de TB |
170 | static struct platform_driver ds1216_rtc_platform_driver = { |
171 | .driver = { | |
172 | .name = "rtc-ds1216", | |
173 | .owner = THIS_MODULE, | |
174 | }, | |
537739de TB |
175 | }; |
176 | ||
061d2a3e | 177 | module_platform_driver_probe(ds1216_rtc_platform_driver, ds1216_rtc_probe); |
537739de TB |
178 | |
179 | MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>"); | |
180 | MODULE_DESCRIPTION("DS1216 RTC driver"); | |
181 | MODULE_LICENSE("GPL"); | |
182 | MODULE_VERSION(DRV_VERSION); | |
ad28a07b | 183 | MODULE_ALIAS("platform:rtc-ds1216"); |