/* * 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 . * * $Id: pcf8563.c,v 1.11 2005/03/07 13:13:07 starvik Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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 numer %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);