Merge branch 'origin' into for-linus
[linux-2.6.git] / drivers / rtc / rtc-ds1302.c
1 /*
2  * Dallas DS1302 RTC Support
3  *
4  *  Copyright (C) 2002 David McCullough
5  *  Copyright (C) 2003 - 2007 Paul Mundt
6  *
7  * This file is subject to the terms and conditions of the GNU General Public
8  * License version 2. See the file "COPYING" in the main directory of
9  * this archive for more details.
10  */
11
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/platform_device.h>
16 #include <linux/rtc.h>
17 #include <linux/io.h>
18 #include <linux/bcd.h>
19 #include <asm/rtc.h>
20
21 #define DRV_NAME        "rtc-ds1302"
22 #define DRV_VERSION     "0.1.1"
23
24 #define RTC_CMD_READ    0x81            /* Read command */
25 #define RTC_CMD_WRITE   0x80            /* Write command */
26
27 #define RTC_ADDR_RAM0   0x20            /* Address of RAM0 */
28 #define RTC_ADDR_TCR    0x08            /* Address of trickle charge register */
29 #define RTC_ADDR_YEAR   0x06            /* Address of year register */
30 #define RTC_ADDR_DAY    0x05            /* Address of day of week register */
31 #define RTC_ADDR_MON    0x04            /* Address of month register */
32 #define RTC_ADDR_DATE   0x03            /* Address of day of month register */
33 #define RTC_ADDR_HOUR   0x02            /* Address of hour register */
34 #define RTC_ADDR_MIN    0x01            /* Address of minute register */
35 #define RTC_ADDR_SEC    0x00            /* Address of second register */
36
37 #define RTC_RESET       0x1000
38 #define RTC_IODATA      0x0800
39 #define RTC_SCLK        0x0400
40
41 #ifdef CONFIG_SH_SECUREEDGE5410
42 #include <mach/snapgear.h>
43 #define set_dp(x)       SECUREEDGE_WRITE_IOPORT(x, 0x1c00)
44 #define get_dp()        SECUREEDGE_READ_IOPORT()
45 #else
46 #error "Add support for your platform"
47 #endif
48
49 static void ds1302_sendbits(unsigned int val)
50 {
51         int i;
52
53         for (i = 8; (i); i--, val >>= 1) {
54                 set_dp((get_dp() & ~RTC_IODATA) | ((val & 0x1) ?
55                         RTC_IODATA : 0));
56                 set_dp(get_dp() | RTC_SCLK);    /* clock high */
57                 set_dp(get_dp() & ~RTC_SCLK);   /* clock low */
58         }
59 }
60
61 static unsigned int ds1302_recvbits(void)
62 {
63         unsigned int val;
64         int i;
65
66         for (i = 0, val = 0; (i < 8); i++) {
67                 val |= (((get_dp() & RTC_IODATA) ? 1 : 0) << i);
68                 set_dp(get_dp() | RTC_SCLK);    /* clock high */
69                 set_dp(get_dp() & ~RTC_SCLK);   /* clock low */
70         }
71
72         return val;
73 }
74
75 static unsigned int ds1302_readbyte(unsigned int addr)
76 {
77         unsigned int val;
78
79         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
80
81         set_dp(get_dp() | RTC_RESET);
82         ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ);
83         val = ds1302_recvbits();
84         set_dp(get_dp() & ~RTC_RESET);
85
86         return val;
87 }
88
89 static void ds1302_writebyte(unsigned int addr, unsigned int val)
90 {
91         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
92         set_dp(get_dp() | RTC_RESET);
93         ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE);
94         ds1302_sendbits(val);
95         set_dp(get_dp() & ~RTC_RESET);
96 }
97
98 static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm)
99 {
100         tm->tm_sec      = bcd2bin(ds1302_readbyte(RTC_ADDR_SEC));
101         tm->tm_min      = bcd2bin(ds1302_readbyte(RTC_ADDR_MIN));
102         tm->tm_hour     = bcd2bin(ds1302_readbyte(RTC_ADDR_HOUR));
103         tm->tm_wday     = bcd2bin(ds1302_readbyte(RTC_ADDR_DAY));
104         tm->tm_mday     = bcd2bin(ds1302_readbyte(RTC_ADDR_DATE));
105         tm->tm_mon      = bcd2bin(ds1302_readbyte(RTC_ADDR_MON)) - 1;
106         tm->tm_year     = bcd2bin(ds1302_readbyte(RTC_ADDR_YEAR));
107
108         if (tm->tm_year < 70)
109                 tm->tm_year += 100;
110
111         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
112                 "mday=%d, mon=%d, year=%d, wday=%d\n",
113                 __func__,
114                 tm->tm_sec, tm->tm_min, tm->tm_hour,
115                 tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday);
116
117         return rtc_valid_tm(tm);
118 }
119
120 static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm)
121 {
122         /* Stop RTC */
123         ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80);
124
125         ds1302_writebyte(RTC_ADDR_SEC, bin2bcd(tm->tm_sec));
126         ds1302_writebyte(RTC_ADDR_MIN, bin2bcd(tm->tm_min));
127         ds1302_writebyte(RTC_ADDR_HOUR, bin2bcd(tm->tm_hour));
128         ds1302_writebyte(RTC_ADDR_DAY, bin2bcd(tm->tm_wday));
129         ds1302_writebyte(RTC_ADDR_DATE, bin2bcd(tm->tm_mday));
130         ds1302_writebyte(RTC_ADDR_MON, bin2bcd(tm->tm_mon + 1));
131         ds1302_writebyte(RTC_ADDR_YEAR, bin2bcd(tm->tm_year % 100));
132
133         /* Start RTC */
134         ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80);
135
136         return 0;
137 }
138
139 static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd,
140                             unsigned long arg)
141 {
142         switch (cmd) {
143 #ifdef RTC_SET_CHARGE
144         case RTC_SET_CHARGE:
145         {
146                 struct ds1302_rtc *rtc = dev_get_drvdata(dev);
147                 int tcs_val;
148
149                 if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int)))
150                         return -EFAULT;
151
152                 ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf));
153                 return 0;
154         }
155 #endif
156         }
157
158         return -ENOIOCTLCMD;
159 }
160
161 static struct rtc_class_ops ds1302_rtc_ops = {
162         .read_time      = ds1302_rtc_read_time,
163         .set_time       = ds1302_rtc_set_time,
164         .ioctl          = ds1302_rtc_ioctl,
165 };
166
167 static int __init ds1302_rtc_probe(struct platform_device *pdev)
168 {
169         struct rtc_device *rtc;
170
171         /* Reset */
172         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
173
174         /* Write a magic value to the DS1302 RAM, and see if it sticks. */
175         ds1302_writebyte(RTC_ADDR_RAM0, 0x42);
176         if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42)
177                 return -ENODEV;
178
179         rtc = rtc_device_register("ds1302", &pdev->dev,
180                                            &ds1302_rtc_ops, THIS_MODULE);
181         if (IS_ERR(rtc))
182                 return PTR_ERR(rtc);
183
184         platform_set_drvdata(pdev, rtc);
185
186         return 0;
187 }
188
189 static int __devexit ds1302_rtc_remove(struct platform_device *pdev)
190 {
191         struct rtc_device *rtc = platform_get_drvdata(pdev);
192
193         rtc_device_unregister(rtc);
194         platform_set_drvdata(pdev, NULL);
195
196         return 0;
197 }
198
199 static struct platform_driver ds1302_platform_driver = {
200         .driver         = {
201                 .name   = DRV_NAME,
202                 .owner  = THIS_MODULE,
203         },
204         .remove         = __exit_p(ds1302_rtc_remove),
205 };
206
207 static int __init ds1302_rtc_init(void)
208 {
209         return platform_driver_probe(&ds1302_platform_driver, ds1302_rtc_probe);
210 }
211
212 static void __exit ds1302_rtc_exit(void)
213 {
214         platform_driver_unregister(&ds1302_platform_driver);
215 }
216
217 module_init(ds1302_rtc_init);
218 module_exit(ds1302_rtc_exit);
219
220 MODULE_DESCRIPTION("Dallas DS1302 RTC driver");
221 MODULE_VERSION(DRV_VERSION);
222 MODULE_AUTHOR("Paul Mundt, David McCullough");
223 MODULE_LICENSE("GPL v2");