b9397818f73a6fd22b118a5643fd768a15b4d5ee
[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 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/platform_device.h>
15 #include <linux/time.h>
16 #include <linux/rtc.h>
17 #include <linux/spinlock.h>
18 #include <linux/io.h>
19 #include <linux/bcd.h>
20 #include <asm/rtc.h>
21
22 #define DRV_NAME        "rtc-ds1302"
23 #define DRV_VERSION     "0.1.0"
24
25 #define RTC_CMD_READ    0x81            /* Read command */
26 #define RTC_CMD_WRITE   0x80            /* Write command */
27
28 #define RTC_ADDR_RAM0   0x20            /* Address of RAM0 */
29 #define RTC_ADDR_TCR    0x08            /* Address of trickle charge register */
30 #define RTC_ADDR_YEAR   0x06            /* Address of year register */
31 #define RTC_ADDR_DAY    0x05            /* Address of day of week register */
32 #define RTC_ADDR_MON    0x04            /* Address of month register */
33 #define RTC_ADDR_DATE   0x03            /* Address of day of month register */
34 #define RTC_ADDR_HOUR   0x02            /* Address of hour register */
35 #define RTC_ADDR_MIN    0x01            /* Address of minute register */
36 #define RTC_ADDR_SEC    0x00            /* Address of second register */
37
38 #define RTC_RESET       0x1000
39 #define RTC_IODATA      0x0800
40 #define RTC_SCLK        0x0400
41
42 #ifdef CONFIG_SH_SECUREEDGE5410
43 #include <asm/snapgear.h>
44 #define set_dp(x)       SECUREEDGE_WRITE_IOPORT(x, 0x1c00)
45 #define get_dp()        SECUREEDGE_READ_IOPORT()
46 #else
47 #error "Add support for your platform"
48 #endif
49
50 struct ds1302_rtc {
51         struct rtc_device *rtc_dev;
52         spinlock_t lock;
53 };
54
55 static void ds1302_sendbits(unsigned int val)
56 {
57         int i;
58
59         for (i = 8; (i); i--, val >>= 1) {
60                 set_dp((get_dp() & ~RTC_IODATA) | ((val & 0x1) ?
61                         RTC_IODATA : 0));
62                 set_dp(get_dp() | RTC_SCLK);    /* clock high */
63                 set_dp(get_dp() & ~RTC_SCLK);   /* clock low */
64         }
65 }
66
67 static unsigned int ds1302_recvbits(void)
68 {
69         unsigned int val;
70         int i;
71
72         for (i = 0, val = 0; (i < 8); i++) {
73                 val |= (((get_dp() & RTC_IODATA) ? 1 : 0) << i);
74                 set_dp(get_dp() | RTC_SCLK);    /* clock high */
75                 set_dp(get_dp() & ~RTC_SCLK);   /* clock low */
76         }
77
78         return val;
79 }
80
81 static unsigned int ds1302_readbyte(unsigned int addr)
82 {
83         unsigned int val;
84
85         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
86
87         set_dp(get_dp() | RTC_RESET);
88         ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ);
89         val = ds1302_recvbits();
90         set_dp(get_dp() & ~RTC_RESET);
91
92         return val;
93 }
94
95 static void ds1302_writebyte(unsigned int addr, unsigned int val)
96 {
97         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
98         set_dp(get_dp() | RTC_RESET);
99         ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE);
100         ds1302_sendbits(val);
101         set_dp(get_dp() & ~RTC_RESET);
102 }
103
104 static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm)
105 {
106         struct ds1302_rtc *rtc = dev_get_drvdata(dev);
107
108         spin_lock_irq(&rtc->lock);
109
110         tm->tm_sec      = BCD2BIN(ds1302_readbyte(RTC_ADDR_SEC));
111         tm->tm_min      = BCD2BIN(ds1302_readbyte(RTC_ADDR_MIN));
112         tm->tm_hour     = BCD2BIN(ds1302_readbyte(RTC_ADDR_HOUR));
113         tm->tm_wday     = BCD2BIN(ds1302_readbyte(RTC_ADDR_DAY));
114         tm->tm_mday     = BCD2BIN(ds1302_readbyte(RTC_ADDR_DATE));
115         tm->tm_mon      = BCD2BIN(ds1302_readbyte(RTC_ADDR_MON)) - 1;
116         tm->tm_year     = BCD2BIN(ds1302_readbyte(RTC_ADDR_YEAR));
117
118         if (tm->tm_year < 70)
119                 tm->tm_year += 100;
120
121         spin_unlock_irq(&rtc->lock);
122
123         dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
124                 "mday=%d, mon=%d, year=%d, wday=%d\n",
125                 __func__,
126                 tm->tm_sec, tm->tm_min, tm->tm_hour,
127                 tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday);
128
129         if (rtc_valid_tm(tm) < 0)
130                 dev_err(dev, "invalid date\n");
131
132         return 0;
133 }
134
135 static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm)
136 {
137         struct ds1302_rtc *rtc = dev_get_drvdata(dev);
138
139         spin_lock_irq(&rtc->lock);
140
141         /* Stop RTC */
142         ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80);
143
144         ds1302_writebyte(RTC_ADDR_SEC, BIN2BCD(tm->tm_sec));
145         ds1302_writebyte(RTC_ADDR_MIN, BIN2BCD(tm->tm_min));
146         ds1302_writebyte(RTC_ADDR_HOUR, BIN2BCD(tm->tm_hour));
147         ds1302_writebyte(RTC_ADDR_DAY, BIN2BCD(tm->tm_wday));
148         ds1302_writebyte(RTC_ADDR_DATE, BIN2BCD(tm->tm_mday));
149         ds1302_writebyte(RTC_ADDR_MON, BIN2BCD(tm->tm_mon + 1));
150         ds1302_writebyte(RTC_ADDR_YEAR, BIN2BCD(tm->tm_year % 100));
151
152         /* Start RTC */
153         ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80);
154
155         spin_unlock_irq(&rtc->lock);
156
157         return 0;
158 }
159
160 static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd,
161                             unsigned long arg)
162 {
163         switch (cmd) {
164 #ifdef RTC_SET_CHARGE
165         case RTC_SET_CHARGE:
166         {
167                 struct ds1302_rtc *rtc = dev_get_drvdata(dev);
168                 int tcs_val;
169
170                 if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int)))
171                         return -EFAULT;
172
173                 spin_lock_irq(&rtc->lock);
174                 ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf));
175                 spin_unlock_irq(&rtc->lock);
176                 return 0;
177         }
178 #endif
179         }
180
181         return -ENOIOCTLCMD;
182 }
183
184 static struct rtc_class_ops ds1302_rtc_ops = {
185         .read_time      = ds1302_rtc_read_time,
186         .set_time       = ds1302_rtc_set_time,
187         .ioctl          = ds1302_rtc_ioctl,
188 };
189
190 static int __devinit ds1302_rtc_probe(struct platform_device *pdev)
191 {
192         struct ds1302_rtc *rtc;
193         int ret;
194
195         /* Reset */
196         set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK));
197
198         /* Write a magic value to the DS1302 RAM, and see if it sticks. */
199         ds1302_writebyte(RTC_ADDR_RAM0, 0x42);
200         if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42)
201                 return -ENODEV;
202
203         rtc = kzalloc(sizeof(struct ds1302_rtc), GFP_KERNEL);
204         if (unlikely(!rtc))
205                 return -ENOMEM;
206
207         spin_lock_init(&rtc->lock);
208         rtc->rtc_dev = rtc_device_register("ds1302", &pdev->dev,
209                                            &ds1302_rtc_ops, THIS_MODULE);
210         if (IS_ERR(rtc->rtc_dev)) {
211                 ret = PTR_ERR(rtc->rtc_dev);
212                 goto out;
213         }
214
215         platform_set_drvdata(pdev, rtc);
216
217         return 0;
218 out:
219         kfree(rtc);
220         return ret;
221 }
222
223 static int __devexit ds1302_rtc_remove(struct platform_device *pdev)
224 {
225         struct ds1302_rtc *rtc = platform_get_drvdata(pdev);
226
227         if (likely(rtc->rtc_dev))
228                 rtc_device_unregister(rtc->rtc_dev);
229
230         platform_set_drvdata(pdev, NULL);
231
232         kfree(rtc);
233
234         return 0;
235 }
236
237 static struct platform_driver ds1302_platform_driver = {
238         .driver         = {
239                 .name   = DRV_NAME,
240                 .owner  = THIS_MODULE,
241         },
242         .probe          = ds1302_rtc_probe,
243         .remove         = __devexit_p(ds1302_rtc_remove),
244 };
245
246 static int __init ds1302_rtc_init(void)
247 {
248         return platform_driver_register(&ds1302_platform_driver);
249 }
250
251 static void __exit ds1302_rtc_exit(void)
252 {
253         platform_driver_unregister(&ds1302_platform_driver);
254 }
255
256 module_init(ds1302_rtc_init);
257 module_exit(ds1302_rtc_exit);
258
259 MODULE_DESCRIPTION("Dallas DS1302 RTC driver");
260 MODULE_VERSION(DRV_VERSION);
261 MODULE_AUTHOR("Paul Mundt, David McCullough");
262 MODULE_LICENSE("GPL v2");