5dfe4c964a
Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. [akpm@osdl.org: sparc64 fix] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
325 lines
7.4 KiB
C
325 lines
7.4 KiB
C
/*
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* PCF8563 RTC
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*
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* From Phillips' datasheet:
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*
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* The PCF8563 is a CMOS real-time clock/calendar optimized for low power
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* consumption. A programmable clock output, interupt output and voltage
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* low detector are also provided. All address and data are transferred
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* serially via two-line bidirectional I2C-bus. Maximum bus speed is
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* 400 kbits/s. The built-in word address register is incremented
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* automatically after each written or read bute.
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*
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* Copyright (c) 2002, Axis Communications AB
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* All rights reserved.
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*
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* Author: Tobias Anderberg <tobiasa@axis.com>.
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*
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* $Id: pcf8563.c,v 1.11 2005/03/07 13:13:07 starvik Exp $
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/ioctl.h>
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#include <linux/delay.h>
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#include <linux/bcd.h>
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#include <linux/capability.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <asm/io.h>
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#include <asm/arch/svinto.h>
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#include <asm/rtc.h>
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#include "i2c.h"
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#define PCF8563_MAJOR 121 /* Local major number. */
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#define DEVICE_NAME "rtc" /* Name which is registered in /proc/devices. */
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#define PCF8563_NAME "PCF8563"
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#define DRIVER_VERSION "$Revision: 1.11 $"
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/* I2C bus slave registers. */
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#define RTC_I2C_READ 0xa3
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#define RTC_I2C_WRITE 0xa2
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/* Two simple wrapper macros, saves a few keystrokes. */
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#define rtc_read(x) i2c_readreg(RTC_I2C_READ, x)
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#define rtc_write(x,y) i2c_writereg(RTC_I2C_WRITE, x, y)
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static DEFINE_SPINLOCK(rtc_lock); /* Protect state etc */
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static const unsigned char days_in_month[] =
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{ 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
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int pcf8563_ioctl(struct inode *, struct file *, unsigned int, unsigned long);
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static const struct file_operations pcf8563_fops = {
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.owner = THIS_MODULE,
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.ioctl = pcf8563_ioctl,
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};
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unsigned char
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pcf8563_readreg(int reg)
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{
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unsigned char res = i2c_readreg(RTC_I2C_READ, reg);
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/* The PCF8563 does not return 0 for unimplemented bits */
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switch(reg)
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{
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case RTC_SECONDS:
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case RTC_MINUTES:
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res &= 0x7f;
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break;
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case RTC_HOURS:
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case RTC_DAY_OF_MONTH:
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res &= 0x3f;
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break;
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case RTC_MONTH:
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res = (res & 0x1f) - 1; /* PCF8563 returns month in range 1-12 */
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break;
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}
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return res;
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}
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void
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pcf8563_writereg(int reg, unsigned char val)
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{
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#ifdef CONFIG_ETRAX_RTC_READONLY
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if (reg == RTC_CONTROL1 || (reg >= RTC_SECONDS && reg <= RTC_YEAR))
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return;
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#endif
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rtc_write(reg, val);
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}
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void
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get_rtc_time(struct rtc_time *tm)
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{
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tm->tm_sec = rtc_read(RTC_SECONDS);
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tm->tm_min = rtc_read(RTC_MINUTES);
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tm->tm_hour = rtc_read(RTC_HOURS);
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tm->tm_mday = rtc_read(RTC_DAY_OF_MONTH);
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tm->tm_mon = rtc_read(RTC_MONTH);
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tm->tm_year = rtc_read(RTC_YEAR);
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if (tm->tm_sec & 0x80)
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printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
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tm->tm_year = BCD_TO_BIN(tm->tm_year) + ((tm->tm_mon & 0x80) ? 100 : 0);
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tm->tm_sec &= 0x7f;
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tm->tm_min &= 0x7f;
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tm->tm_hour &= 0x3f;
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tm->tm_mday &= 0x3f;
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tm->tm_mon &= 0x1f;
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BCD_TO_BIN(tm->tm_sec);
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BCD_TO_BIN(tm->tm_min);
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BCD_TO_BIN(tm->tm_hour);
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BCD_TO_BIN(tm->tm_mday);
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BCD_TO_BIN(tm->tm_mon);
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tm->tm_mon--; /* Month is 1..12 in RTC but 0..11 in linux */
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}
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int __init
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pcf8563_init(void)
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{
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int ret;
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if ((ret = i2c_init())) {
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printk(KERN_CRIT "pcf8563_init: failed to init i2c\n");
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return ret;
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}
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/*
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* First of all we need to reset the chip. This is done by
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* clearing control1, control2 and clk freq, clear the
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* Voltage Low bit, and resetting all alarms.
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*/
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if (rtc_write(RTC_CONTROL1, 0x00) < 0)
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goto err;
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if (rtc_write(RTC_CONTROL2, 0x00) < 0)
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goto err;
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if (rtc_write(RTC_CLOCKOUT_FREQ, 0x00) < 0)
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goto err;
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/* Clear the VL bit in the seconds register. */
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ret = rtc_read(RTC_SECONDS);
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if (rtc_write(RTC_SECONDS, (ret & 0x7f)) < 0)
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goto err;
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/* Reset the alarms. */
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if (rtc_write(RTC_MINUTE_ALARM, 0x00) < 0)
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goto err;
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if (rtc_write(RTC_HOUR_ALARM, 0x00) < 0)
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goto err;
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if (rtc_write(RTC_DAY_ALARM, 0x00) < 0)
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goto err;
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if (rtc_write(RTC_WEEKDAY_ALARM, 0x00) < 0)
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goto err;
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/* Check for low voltage, and warn about it.. */
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if (rtc_read(RTC_SECONDS) & 0x80)
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printk(KERN_WARNING "%s: RTC Low Voltage - date/time is not reliable!\n", PCF8563_NAME);
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return 0;
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err:
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printk(KERN_INFO "%s: Error initializing chip.\n", PCF8563_NAME);
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return -1;
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}
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void __exit
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pcf8563_exit(void)
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{
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if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
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printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
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}
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}
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/*
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* ioctl calls for this driver. Why return -ENOTTY upon error? Because
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* POSIX says so!
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*/
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int
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pcf8563_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
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{
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/* Some sanity checks. */
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if (_IOC_TYPE(cmd) != RTC_MAGIC)
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return -ENOTTY;
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if (_IOC_NR(cmd) > RTC_MAX_IOCTL)
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return -ENOTTY;
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switch (cmd) {
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case RTC_RD_TIME:
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{
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struct rtc_time tm;
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spin_lock(&rtc_lock);
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get_rtc_time(&tm);
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if (copy_to_user((struct rtc_time *) arg, &tm, sizeof(struct rtc_time))) {
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spin_unlock(&rtc_lock);
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return -EFAULT;
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}
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spin_unlock(&rtc_lock);
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return 0;
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}
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break;
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case RTC_SET_TIME:
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{
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#ifdef CONFIG_ETRAX_RTC_READONLY
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return -EPERM;
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#else
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int leap;
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int century;
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struct rtc_time tm;
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memset(&tm, 0, sizeof (struct rtc_time));
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if (!capable(CAP_SYS_TIME))
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return -EPERM;
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if (copy_from_user(&tm, (struct rtc_time *) arg, sizeof(struct rtc_time)))
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return -EFAULT;
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/* Convert from struct tm to struct rtc_time. */
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tm.tm_year += 1900;
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tm.tm_mon += 1;
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leap = ((tm.tm_mon == 2) && ((tm.tm_year % 4) == 0)) ? 1 : 0;
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/* Perform some sanity checks. */
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if ((tm.tm_year < 1970) ||
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(tm.tm_mon > 12) ||
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(tm.tm_mday == 0) ||
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(tm.tm_mday > days_in_month[tm.tm_mon] + leap) ||
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(tm.tm_hour >= 24) ||
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(tm.tm_min >= 60) ||
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(tm.tm_sec >= 60))
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return -EINVAL;
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century = (tm.tm_year >= 2000) ? 0x80 : 0;
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tm.tm_year = tm.tm_year % 100;
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BIN_TO_BCD(tm.tm_year);
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BIN_TO_BCD(tm.tm_mday);
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BIN_TO_BCD(tm.tm_hour);
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BIN_TO_BCD(tm.tm_min);
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BIN_TO_BCD(tm.tm_sec);
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tm.tm_mon |= century;
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spin_lock(&rtc_lock);
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rtc_write(RTC_YEAR, tm.tm_year);
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rtc_write(RTC_MONTH, tm.tm_mon);
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rtc_write(RTC_DAY_OF_MONTH, tm.tm_mday);
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rtc_write(RTC_HOURS, tm.tm_hour);
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rtc_write(RTC_MINUTES, tm.tm_min);
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rtc_write(RTC_SECONDS, tm.tm_sec);
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spin_unlock(&rtc_lock);
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return 0;
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#endif /* !CONFIG_ETRAX_RTC_READONLY */
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}
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case RTC_VLOW_RD:
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{
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int vl_bit = 0;
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if (rtc_read(RTC_SECONDS) & 0x80) {
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vl_bit = 1;
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printk(KERN_WARNING "%s: RTC Voltage Low - reliable "
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"date/time information is no longer guaranteed!\n",
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PCF8563_NAME);
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}
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if (copy_to_user((int *) arg, &vl_bit, sizeof(int)))
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return -EFAULT;
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return 0;
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}
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case RTC_VLOW_SET:
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{
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/* Clear the VL bit in the seconds register */
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int ret = rtc_read(RTC_SECONDS);
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rtc_write(RTC_SECONDS, (ret & 0x7F));
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return 0;
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}
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default:
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return -ENOTTY;
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}
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return 0;
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}
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static int __init
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pcf8563_register(void)
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{
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pcf8563_init();
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if (register_chrdev(PCF8563_MAJOR, DEVICE_NAME, &pcf8563_fops) < 0) {
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printk(KERN_INFO "%s: Unable to get major numer %d for RTC device.\n",
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PCF8563_NAME, PCF8563_MAJOR);
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return -1;
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}
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printk(KERN_INFO "%s Real-Time Clock Driver, %s\n", PCF8563_NAME, DRIVER_VERSION);
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return 0;
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}
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module_init(pcf8563_register);
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module_exit(pcf8563_exit);
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