aboutsummaryrefslogtreecommitdiffstats
path: root/arch/cris/arch-v10/drivers/pcf8563.c
blob: d47cfbf98d6e0b1487500ca2292997423f8da2e7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
/*
 * PCF8563 RTC
 *
 * From Phillips' datasheet:
 *
 * The PCF8563 is a CMOS real-time clock/calendar optimized for low power
 * consumption. A programmable clock output, interupt output and voltage
 * low detector are also provided. All address and data are transferred
 * serially via two-line bidirectional I2C-bus. Maximum bus speed is
 * 400 kbits/s. The built-in word address register is incremented
 * automatically after each written or read bute.
 *
 * Copyright (c) 2002, Axis Communications AB
 * All rights reserved.
 *
 * Author: Tobias Anderberg <tobiasa@axis.com>.
 *
 * $Id: pcf8563.c,v 1.11 2005/03/07 13:13:07 starvik Exp $
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/delay.h>
#include <linux/bcd.h>
#include <linux/capability.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/arch/svinto.h>
#include <asm/rtc.h>
#include "i2c.h"

#define PCF8563_MAJOR 121		/* Local major number. */
#define DEVICE_NAME "rtc"		/* Name which is registered in /proc/devices. */
#define PCF8563_NAME "PCF8563"
#define DRIVER_VERSION "$Revision: 1.11 $"

/* I2C bus slave registers. */
#define RTC_I2C_READ		0xa3
#define RTC_I2C_WRITE		0xa2

/* Two simple wrapper macros, saves a few keystrokes. */
#define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
#define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)

static DEFINE_SPINLOCK(rtc_lock); /* Protect state etc */
	
static const unsigned char days_in_month[] =
	{ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

int pcf8563_ioctl(struct inode *, struct file *, unsigned int, unsigned long);

static const struct file_operations pcf8563_fops = {
	.owner = THIS_MODULE,
	.ioctl = pcf8563_ioctl,
};

unsigned char
pcf8563_readreg(int reg) 
{
	unsigned char res = i2c_readreg(RTC_I2C_READ, reg);

	/* The PCF8563 does not return 0 for unimplemented bits */
	switch(reg)
	{
		case RTC_SECONDS:
		case RTC_MINUTES:
		     res &= 0x7f;
		     break;
		case RTC_HOURS:
		case RTC_DAY_OF_MONTH:
		     res &= 0x3f;
		     break;
		case RTC_MONTH:
		     res = (res & 0x1f) - 1;  /* PCF8563 returns month in range 1-12 */
		     break;
	}
	return res;
}

void
pcf8563_writereg(int reg, unsigned char val) 
{
#ifdef CONFIG_ETRAX_RTC_READONLY
	if (reg == RTC_CONTROL1 || (reg >= RTC_SECONDS && reg <= RTC_YEAR))
		return;
#endif

	rtc_write(reg, val);
}

void
get_rtc_time(struct rtc_time *tm)
{
	tm->tm_sec = rtc_read(RTC_SECONDS);
	tm->tm_min = rtc_read(RTC_MINUTES);
	tm->tm_hour = rtc_read(RTC_HOURS);
	tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
	tm->tm_mon = rtc_read(RTC_MONTH);
	tm->tm_year = rtc_read(RTC_YEAR);

	if (tm->tm_sec & 0x80)
		printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);

	tm->tm_year = BCD_TO_BIN(tm->tm_year) + ((tm->tm_mon & 0x80) ? 100 : 0);
	tm->tm_sec &= 0x7f;
	tm->tm_min &= 0x7f;
	tm->tm_hour &= 0x3f;
	tm->tm_mday &= 0x3f;
	tm->tm_mon &= 0x1f;

	BCD_TO_BIN(tm->tm_sec);
	BCD_TO_BIN(tm->tm_min);
	BCD_TO_BIN(tm->tm_hour);
	BCD_TO_BIN(tm->tm_mday);
	BCD_TO_BIN(tm->tm_mon);
	tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
}

int __init
pcf8563_init(void)
{
	int ret;

	if ((ret = i2c_init())) {
		printk(KERN_CRIT "pcf8563_init: failed to init i2c\n");
		return ret;
	}

	/*
	 * First of all we need to reset the chip. This is done by
	 * clearing control1, control2 and clk freq, clear the 
	 * Voltage Low bit, and resetting all alarms.
	 */
	if (rtc_write(RTC_CONTROL1, 0x00) < 0)
		goto err;

	if (rtc_write(RTC_CONTROL2, 0x00) < 0)
		goto err;

	if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
		goto err;

	/* Clear the VL bit in the seconds register. */
	ret = rtc_read(RTC_SECONDS);
	
	if (rtc_write(RTC_SECONDS, (ret & 0x7f)) < 0)
		goto err;
		
	/* Reset the alarms. */
	if (rtc_write(RTC_MINUTE_ALARM, 0x00) < 0)
		goto err;
	
	if (rtc_write(RTC_HOUR_ALARM, 0x00) < 0)
		goto err;
	
	if (rtc_write(RTC_DAY_ALARM, 0x00) < 0)
		goto err;
	
	if (rtc_write(RTC_WEEKDAY_ALARM, 0x00) < 0)
		goto err;
        
	/* Check for low voltage, and warn about it.. */
	if (rtc_read(RTC_SECONDS) & 0x80)
		printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
	
	return 0;

err:
	printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
	return -1;
}

void __exit
pcf8563_exit(void)
{
	if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
		printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
	}
}

/*
 * ioctl calls for this driver. Why return -ENOTTY upon error? Because
 * POSIX says so!
 */
int
pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
{
	/* Some sanity checks. */
	if (_IOC_TYPE(cmd) != RTC_MAGIC)
		return -ENOTTY;

	if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
		return -ENOTTY;

	switch (cmd) {
		case RTC_RD_TIME:
			{
				struct rtc_time tm;

				spin_lock(&rtc_lock);
				get_rtc_time(&tm);

				if (copy_to_user((struct rtc_time *) arg, &tm, sizeof(struct rtc_time))) {
					spin_unlock(&rtc_lock);
					return -EFAULT;
				}

				spin_unlock(&rtc_lock);
				return 0;
			}
			break;
		case RTC_SET_TIME:
			{
#ifdef CONFIG_ETRAX_RTC_READONLY
				return -EPERM;
#else
				int leap;
				int century;
				struct rtc_time tm;

				memset(&tm, 0, sizeof (struct rtc_time));
				if (!capable(CAP_SYS_TIME))
					return -EPERM;

				if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time)))
					return -EFAULT;

				/* Convert from struct tm to struct rtc_time. */
				tm.tm_year += 1900;
				tm.tm_mon += 1;
				
				leap = ((tm.tm_mon == 2) && ((tm.tm_year % 4) == 0)) ? 1 : 0;

				/* Perform some sanity checks. */
				if ((tm.tm_year < 1970) ||
				    (tm.tm_mon > 12) ||
				    (tm.tm_mday == 0) ||
				    (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
				    (tm.tm_hour >= 24) ||
				    (tm.tm_min >= 60) ||
				    (tm.tm_sec >= 60))
					return -EINVAL;

				century = (tm.tm_year >= 2000) ? 0x80 : 0;
				tm.tm_year = tm.tm_year % 100;

				BIN_TO_BCD(tm.tm_year);
				BIN_TO_BCD(tm.tm_mday);
				BIN_TO_BCD(tm.tm_hour);
				BIN_TO_BCD(tm.tm_min);
				BIN_TO_BCD(tm.tm_sec);
				tm.tm_mon |= century;

				spin_lock(&rtc_lock);
				
				rtc_write(RTC_YEAR, tm.tm_year);
				rtc_write(RTC_MONTH, tm.tm_mon);
				rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
				rtc_write(RTC_HOURS, tm.tm_hour);
				rtc_write(RTC_MINUTES, tm.tm_min);
				rtc_write(RTC_SECONDS, tm.tm_sec);

				spin_unlock(&rtc_lock);

				return 0;
#endif /* !CONFIG_ETRAX_RTC_READONLY */
			}

		case RTC_VLOW_RD:
		{
			int vl_bit = 0;

			if (rtc_read(RTC_SECONDS) & 0x80) {
				vl_bit = 1;
				printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
				       "date/time information is no longer guaranteed!\n",
				       PCF8563_NAME);
			}
			if (copy_to_user((int *) arg, &vl_bit, sizeof(int)))
				return -EFAULT;

			return 0;
		}

		case RTC_VLOW_SET:
		{
			/* Clear the VL bit in the seconds register */
			int ret = rtc_read(RTC_SECONDS);

			rtc_write(RTC_SECONDS, (ret & 0x7F));

			return 0;
		}

		default:
				return -ENOTTY;
	}

	return 0;
}

static int __init
pcf8563_register(void)
{
	pcf8563_init();
	if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
		printk(KERN_INFO "%s: Unable to get major number %d for RTC device.\n",
		       PCF8563_NAME, PCF8563_MAJOR);
		return -1;
	}

	printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
        return 0;
}

module_init(pcf8563_register);
module_exit(pcf8563_exit);