aboutsummaryrefslogtreecommitdiffstats
path: root/arch/cris/arch-v10/drivers/pcf8563.c
blob: ea69faba9b6212f00a731652e96966ed1116186c (plain) (blame)
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
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
/*
 * PCF8563 RTC
 *
 * From Phillips' datasheet:
 *
 * The PCF8563 is a CMOS real-time clock/calendar optimized for low power
 * consumption. A programmable clock output, interrupt 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 byte.
 *
 * Copyright (c) 2002-2007, Axis Communications AB
 * All rights reserved.
 *
 * Author: Tobias Anderberg <tobiasa@axis.com>.
 *
 */

#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/mutex.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.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: 1.24 $"

/* 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_MUTEX(pcf8563_mutex);
static DEFINE_MUTEX(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 };

static long pcf8563_unlocked_ioctl(struct file *, unsigned int, unsigned long);

/* Cache VL bit value read at driver init since writing the RTC_SECOND
 * register clears the VL status.
 */
static int voltage_low;

static const struct file_operations pcf8563_fops = {
	.owner = THIS_MODULE,
	.unlocked_ioctl = pcf8563_unlocked_ioctl,
	.llseek		= noop_llseek,
};

unsigned char
pcf8563_readreg(int reg)
{
	unsigned char res = rtc_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_WEEKDAY:
		res &= 0x07;
		break;
	case RTC_MONTH:
		res &= 0x1F;
		break;
	case RTC_CONTROL1:
		res &= 0xA8;
		break;
	case RTC_CONTROL2:
		res &= 0x1F;
		break;
	case RTC_CLOCKOUT_FREQ:
	case RTC_TIMER_CONTROL:
		res &= 0x83;
		break;
	}
	return res;
}

void
pcf8563_writereg(int reg, unsigned char val)
{
	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_wday = rtc_read(RTC_WEEKDAY);
	tm->tm_mon  = rtc_read(RTC_MONTH);
	tm->tm_year = rtc_read(RTC_YEAR);

	if (tm->tm_sec & 0x80) {
		printk(KERN_ERR "%s: RTC Voltage Low - reliable date/time "
		       "information is no longer guaranteed!\n", PCF8563_NAME);
	}

	tm->tm_year  = bcd2bin(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_wday &= 0x07; /* Not coded in BCD. */
	tm->tm_mon  &= 0x1F;

	tm->tm_sec = bcd2bin(tm->tm_sec);
	tm->tm_min = bcd2bin(tm->tm_min);
	tm->tm_hour = bcd2bin(tm->tm_hour);
	tm->tm_mday = bcd2bin(tm->tm_mday);
	tm->tm_mon = bcd2bin(tm->tm_mon);
	tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
}

int __init
pcf8563_init(void)
{
	static int res;
	static int first = 1;

	if (!first)
		return res;
	first = 0;

	/* Initiate the i2c protocol. */
	res = i2c_init();
	if (res < 0) {
		printk(KERN_CRIT "pcf8563_init: Failed to init i2c.\n");
		return res;
	}

	/*
	 * First of all we need to reset the chip. This is done by
	 * clearing control1, control2 and clk freq 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;

	if (rtc_write(RTC_TIMER_CONTROL, 0x03) < 0)
		goto err;

	/* Reset the alarms. */
	if (rtc_write(RTC_MINUTE_ALARM, 0x80) < 0)
		goto err;

	if (rtc_write(RTC_HOUR_ALARM, 0x80) < 0)
		goto err;

	if (rtc_write(RTC_DAY_ALARM, 0x80) < 0)
		goto err;

	if (rtc_write(RTC_WEEKDAY_ALARM, 0x80) < 0)
		goto err;

	/* Check for low voltage, and warn about it. */
	if (rtc_read(RTC_SECONDS) & 0x80) {
		voltage_low = 1;
		printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
		       "date/time information is no longer guaranteed!\n",
		       PCF8563_NAME);
	}

	return res;

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

void __exit
pcf8563_exit(void)
{
	unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME);
}

/*
 * ioctl calls for this driver. Why return -ENOTTY upon error? Because
 * POSIX says so!
 */
static int pcf8563_ioctl(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;

		mutex_lock(&rtc_lock);
		memset(&tm, 0, sizeof tm);
		get_rtc_time(&tm);

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

		mutex_unlock(&rtc_lock);

		return 0;
	}
	case RTC_SET_TIME:
	{
		int leap;
		int year;
		int century;
		struct rtc_time tm;

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

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

		/* Convert from struct tm to struct rtc_time. */
		tm.tm_year += 1900;
		tm.tm_mon += 1;

		/*
		 * Check if tm.tm_year is a leap year. A year is a leap
		 * year if it is divisible by 4 but not 100, except
		 * that years divisible by 400 _are_ leap years.
		 */
		year = tm.tm_year;
		leap = (tm.tm_mon == 2) &&
			((year % 4 == 0 && year % 100 != 0) || year % 400 == 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_wday >= 7) ||
		    (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;

		tm.tm_year = bin2bcd(tm.tm_year);
		tm.tm_mon = bin2bcd(tm.tm_mon);
		tm.tm_mday = bin2bcd(tm.tm_mday);
		tm.tm_hour = bin2bcd(tm.tm_hour);
		tm.tm_min = bin2bcd(tm.tm_min);
		tm.tm_sec = bin2bcd(tm.tm_sec);
		tm.tm_mon |= century;

		mutex_lock(&rtc_lock);

		rtc_write(RTC_YEAR, tm.tm_year);
		rtc_write(RTC_MONTH, tm.tm_mon);
		rtc_write(RTC_WEEKDAY, tm.tm_wday); /* Not coded in BCD. */
		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);

		mutex_unlock(&rtc_lock);

		return 0;
	}
	case RTC_VL_READ:
		if (voltage_low) {
			printk(KERN_ERR "%s: RTC Voltage Low - "
			       "reliable date/time information is no "
			       "longer guaranteed!\n", PCF8563_NAME);
		}

		if (copy_to_user((int *) arg, &voltage_low, sizeof(int)))
			return -EFAULT;
		return 0;

	case RTC_VL_CLR:
	{
		/* Clear the VL bit in the seconds register in case
		 * the time has not been set already (which would
		 * have cleared it). This does not really matter
		 * because of the cached voltage_low value but do it
		 * anyway for consistency. */

		int ret = rtc_read(RTC_SECONDS);

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

		/* Clear the cached value. */
		voltage_low = 0;

		return 0;
	}
	default:
		return -ENOTTY;
	}

	return 0;
}

static long pcf8563_unlocked_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	int ret;

	mutex_lock(&pcf8563_mutex);
	return pcf8563_ioctl(filp, cmd, arg);
	mutex_unlock(&pcf8563_mutex);

	return ret;
}

static int __init pcf8563_register(void)
{
	if (pcf8563_init() < 0) {
		printk(KERN_INFO "%s: Unable to initialize Real-Time Clock "
		       "Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
		return -1;
	}

	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);

	/* Check for low voltage, and warn about it. */
	if (voltage_low) {
		printk(KERN_WARNING "%s: RTC Voltage Low - reliable date/time "
		       "information is no longer guaranteed!\n", PCF8563_NAME);
	}

	return 0;
}

module_init(pcf8563_register);
module_exit(pcf8563_exit);