4 * From Phillips' datasheet:
6 * The PCF8563 is a CMOS real-time clock/calendar optimized for low power
7 * consumption. A programmable clock output, interupt output and voltage
8 * low detector are also provided. All address and data are transferred
9 * serially via two-line bidirectional I2C-bus. Maximum bus speed is
10 * 400 kbits/s. The built-in word address register is incremented
11 * automatically after each written or read bute.
13 * Copyright (c) 2002, Axis Communications AB
14 * All rights reserved.
16 * Author: Tobias Anderberg <tobiasa@axis.com>.
18 * $Id: pcf8563.c,v 1.1 2002/12/12 08:27:26 starvik Exp $
21 #include <linux/config.h>
22 #include <linux/version.h>
23 #include <linux/module.h>
24 #include <linux/kernel.h>
25 #include <linux/types.h>
26 #include <linux/sched.h>
27 #include <linux/init.h>
29 #include <linux/ioctl.h>
30 #include <linux/delay.h>
32 #include <asm/uaccess.h>
33 #include <asm/system.h>
35 #include <asm/arch/svinto.h>
39 #define PCF8563_MAJOR 121 /* Local major number. */
40 #define DEVICE_NAME "rtc" /* Name which is registered in /proc/devices. */
41 #define PCF8563_NAME "PCF8563"
42 #define DRIVER_VERSION "$Revision: 1.1 $"
44 /* I2C bus slave registers. */
45 #define RTC_I2C_READ 0xa3
46 #define RTC_I2C_WRITE 0xa2
48 /* Two simple wrapper macros, saves a few keystrokes. */
49 #define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
50 #define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)
52 static const unsigned char days_in_month[] =
53 { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
55 int pcf8563_ioctl(struct inode *, struct file *, unsigned int, unsigned long);
56 int pcf8563_open(struct inode *, struct file *);
57 int pcf8563_release(struct inode *, struct file *);
59 static struct file_operations pcf8563_fops = {
61 .ioctl = pcf8563_ioctl,
63 .release = pcf8563_release,
67 pcf8563_readreg(int reg)
69 unsigned char res = i2c_readreg(RTC_I2C_READ, reg);
71 /* The PCF8563 does not return 0 for unimplemented bits */
79 case RTC_DAY_OF_MONTH:
83 res = (res & 0x1f) - 1; /* PCF8563 returns month in range 1-12 */
90 pcf8563_writereg(int reg, unsigned char val)
92 i2c_writereg(RTC_I2C_WRITE,reg,val);
96 get_rtc_time(struct rtc_time *tm)
98 tm->tm_sec = rtc_read(RTC_SECONDS);
99 tm->tm_min = rtc_read(RTC_MINUTES);
100 tm->tm_hour = rtc_read(RTC_HOURS);
101 tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
102 tm->tm_mon = rtc_read(RTC_MONTH);
103 tm->tm_year = rtc_read(RTC_YEAR);
105 if (tm->tm_sec & 0x80)
106 printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
108 tm->tm_year = BCD_TO_BIN(tm->tm_year) + ((tm->tm_mon & 0x80) ? 100 : 0);
115 BCD_TO_BIN(tm->tm_sec);
116 BCD_TO_BIN(tm->tm_min);
117 BCD_TO_BIN(tm->tm_hour);
118 BCD_TO_BIN(tm->tm_mday);
119 BCD_TO_BIN(tm->tm_mon);
120 tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
128 * First of all we need to reset the chip. This is done by
129 * clearing control1, control2 and clk freq, clear the
130 * Voltage Low bit, and resetting all alarms.
132 if (rtc_write(RTC_CONTROL1, 0x00) < 0)
135 if (rtc_write(RTC_CONTROL2, 0x00) < 0)
138 if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
141 /* Clear the VL bit in the seconds register. */
142 ret = rtc_read(RTC_SECONDS);
144 if (rtc_write(RTC_SECONDS, (ret & 0x7f)) < 0)
147 /* Reset the alarms. */
148 if (rtc_write(RTC_MINUTE_ALARM, 0x00) < 0)
151 if (rtc_write(RTC_HOUR_ALARM, 0x00) < 0)
154 if (rtc_write(RTC_DAY_ALARM, 0x00) < 0)
157 if (rtc_write(RTC_WEEKDAY_ALARM, 0x00) < 0)
160 if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
161 printk(KERN_INFO "%s: Unable to get major numer %d for RTC device.\n",
162 PCF8563_NAME, PCF8563_MAJOR);
166 printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
168 /* Check for low voltage, and warn about it.. */
169 if (rtc_read(RTC_SECONDS) & 0x80)
170 printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
175 printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
182 if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
183 printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
188 * ioctl calls for this driver. Why return -ENOTTY upon error? Because
192 pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
194 /* Some sanity checks. */
195 if (_IOC_TYPE(cmd) != RTC_MAGIC)
198 if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
208 if (copy_to_user((struct rtc_time *) arg, &tm, sizeof(struct rtc_time))) {
222 memset(&tm, 0, sizeof (struct rtc_time));
223 if (!capable(CAP_SYS_TIME))
226 if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time)))
229 /* Convert from struct tm to struct rtc_time. */
233 leap = ((tm.tm_mon == 2) && ((tm.tm_year % 4) == 0)) ? 1 : 0;
235 /* Perform some sanity checks. */
236 if ((tm.tm_year < 1970) ||
239 (tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
240 (tm.tm_hour >= 24) ||
245 century = (tm.tm_year >= 2000) ? 0x80 : 0;
246 tm.tm_year = tm.tm_year % 100;
248 BIN_TO_BCD(tm.tm_year);
249 BIN_TO_BCD(tm.tm_mday);
250 BIN_TO_BCD(tm.tm_hour);
251 BIN_TO_BCD(tm.tm_min);
252 BIN_TO_BCD(tm.tm_sec);
253 tm.tm_mon |= century;
255 rtc_write(RTC_YEAR, tm.tm_year);
256 rtc_write(RTC_MONTH, tm.tm_mon);
257 rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
258 rtc_write(RTC_HOURS, tm.tm_hour);
259 rtc_write(RTC_MINUTES, tm.tm_min);
260 rtc_write(RTC_SECONDS, tm.tm_sec);
273 pcf8563_open(struct inode *inode, struct file *filp)
280 pcf8563_release(struct inode *inode, struct file *filp)
286 module_init(pcf8563_init);
287 module_exit(pcf8563_exit);