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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/char/ds1286.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/char/ds1286.c')
-rw-r--r-- | drivers/char/ds1286.c | 578 |
1 files changed, 578 insertions, 0 deletions
diff --git a/drivers/char/ds1286.c b/drivers/char/ds1286.c new file mode 100644 index 000000000000..d755cac14bc1 --- /dev/null +++ b/drivers/char/ds1286.c @@ -0,0 +1,578 @@ +/* + * DS1286 Real Time Clock interface for Linux + * + * Copyright (C) 1998, 1999, 2000 Ralf Baechle + * + * Based on code written by Paul Gortmaker. + * + * This driver allows use of the real time clock (built into nearly all + * computers) from user space. It exports the /dev/rtc interface supporting + * various ioctl() and also the /proc/rtc pseudo-file for status + * information. + * + * The ioctls can be used to set the interrupt behaviour and generation rate + * from the RTC via IRQ 8. Then the /dev/rtc interface can be used to make + * use of these timer interrupts, be they interval or alarm based. + * + * The /dev/rtc interface will block on reads until an interrupt has been + * received. If a RTC interrupt has already happened, it will output an + * unsigned long and then block. The output value contains the interrupt + * status in the low byte and the number of interrupts since the last read + * in the remaining high bytes. The /dev/rtc interface can also be used with + * the select(2) call. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + */ +#include <linux/ds1286.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/miscdevice.h> +#include <linux/slab.h> +#include <linux/ioport.h> +#include <linux/fcntl.h> +#include <linux/init.h> +#include <linux/poll.h> +#include <linux/rtc.h> +#include <linux/spinlock.h> +#include <linux/bcd.h> +#include <linux/proc_fs.h> + +#include <asm/uaccess.h> +#include <asm/system.h> + +#define DS1286_VERSION "1.0" + +/* + * We sponge a minor off of the misc major. No need slurping + * up another valuable major dev number for this. If you add + * an ioctl, make sure you don't conflict with SPARC's RTC + * ioctls. + */ + +static DECLARE_WAIT_QUEUE_HEAD(ds1286_wait); + +static ssize_t ds1286_read(struct file *file, char *buf, + size_t count, loff_t *ppos); + +static int ds1286_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg); + +static unsigned int ds1286_poll(struct file *file, poll_table *wait); + +static void ds1286_get_alm_time (struct rtc_time *alm_tm); +static void ds1286_get_time(struct rtc_time *rtc_tm); +static int ds1286_set_time(struct rtc_time *rtc_tm); + +static inline unsigned char ds1286_is_updating(void); + +static DEFINE_SPINLOCK(ds1286_lock); + +static int ds1286_read_proc(char *page, char **start, off_t off, + int count, int *eof, void *data); + +/* + * Bits in rtc_status. (7 bits of room for future expansion) + */ + +#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ +#define RTC_TIMER_ON 0x02 /* missed irq timer active */ + +static unsigned char ds1286_status; /* bitmapped status byte. */ + +static unsigned char days_in_mo[] = { + 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 +}; + +/* + * Now all the various file operations that we export. + */ + +static ssize_t ds1286_read(struct file *file, char *buf, + size_t count, loff_t *ppos) +{ + return -EIO; +} + +static int ds1286_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct rtc_time wtime; + + switch (cmd) { + case RTC_AIE_OFF: /* Mask alarm int. enab. bit */ + { + unsigned int flags; + unsigned char val; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + spin_lock_irqsave(&ds1286_lock, flags); + val = rtc_read(RTC_CMD); + val |= RTC_TDM; + rtc_write(val, RTC_CMD); + spin_unlock_irqrestore(&ds1286_lock, flags); + + return 0; + } + case RTC_AIE_ON: /* Allow alarm interrupts. */ + { + unsigned int flags; + unsigned char val; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + spin_lock_irqsave(&ds1286_lock, flags); + val = rtc_read(RTC_CMD); + val &= ~RTC_TDM; + rtc_write(val, RTC_CMD); + spin_unlock_irqrestore(&ds1286_lock, flags); + + return 0; + } + case RTC_WIE_OFF: /* Mask watchdog int. enab. bit */ + { + unsigned int flags; + unsigned char val; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + spin_lock_irqsave(&ds1286_lock, flags); + val = rtc_read(RTC_CMD); + val |= RTC_WAM; + rtc_write(val, RTC_CMD); + spin_unlock_irqrestore(&ds1286_lock, flags); + + return 0; + } + case RTC_WIE_ON: /* Allow watchdog interrupts. */ + { + unsigned int flags; + unsigned char val; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + spin_lock_irqsave(&ds1286_lock, flags); + val = rtc_read(RTC_CMD); + val &= ~RTC_WAM; + rtc_write(val, RTC_CMD); + spin_unlock_irqrestore(&ds1286_lock, flags); + + return 0; + } + case RTC_ALM_READ: /* Read the present alarm time */ + { + /* + * This returns a struct rtc_time. Reading >= 0xc0 + * means "don't care" or "match all". Only the tm_hour, + * tm_min, and tm_sec values are filled in. + */ + + memset(&wtime, 0, sizeof(wtime)); + ds1286_get_alm_time(&wtime); + break; + } + case RTC_ALM_SET: /* Store a time into the alarm */ + { + /* + * This expects a struct rtc_time. Writing 0xff means + * "don't care" or "match all". Only the tm_hour, + * tm_min and tm_sec are used. + */ + unsigned char hrs, min, sec; + struct rtc_time alm_tm; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + if (copy_from_user(&alm_tm, (struct rtc_time*)arg, + sizeof(struct rtc_time))) + return -EFAULT; + + hrs = alm_tm.tm_hour; + min = alm_tm.tm_min; + + if (hrs >= 24) + hrs = 0xff; + + if (min >= 60) + min = 0xff; + + BIN_TO_BCD(sec); + BIN_TO_BCD(min); + BIN_TO_BCD(hrs); + + spin_lock(&ds1286_lock); + rtc_write(hrs, RTC_HOURS_ALARM); + rtc_write(min, RTC_MINUTES_ALARM); + spin_unlock(&ds1286_lock); + + return 0; + } + case RTC_RD_TIME: /* Read the time/date from RTC */ + { + memset(&wtime, 0, sizeof(wtime)); + ds1286_get_time(&wtime); + break; + } + case RTC_SET_TIME: /* Set the RTC */ + { + struct rtc_time rtc_tm; + + if (!capable(CAP_SYS_TIME)) + return -EACCES; + + if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, + sizeof(struct rtc_time))) + return -EFAULT; + + return ds1286_set_time(&rtc_tm); + } + default: + return -EINVAL; + } + return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0; +} + +/* + * We enforce only one user at a time here with the open/close. + * Also clear the previous interrupt data on an open, and clean + * up things on a close. + */ + +static int ds1286_open(struct inode *inode, struct file *file) +{ + spin_lock_irq(&ds1286_lock); + + if (ds1286_status & RTC_IS_OPEN) + goto out_busy; + + ds1286_status |= RTC_IS_OPEN; + + spin_unlock_irq(&ds1286_lock); + return 0; + +out_busy: + spin_lock_irq(&ds1286_lock); + return -EBUSY; +} + +static int ds1286_release(struct inode *inode, struct file *file) +{ + ds1286_status &= ~RTC_IS_OPEN; + + return 0; +} + +static unsigned int ds1286_poll(struct file *file, poll_table *wait) +{ + poll_wait(file, &ds1286_wait, wait); + + return 0; +} + +/* + * The various file operations we support. + */ + +static struct file_operations ds1286_fops = { + .llseek = no_llseek, + .read = ds1286_read, + .poll = ds1286_poll, + .ioctl = ds1286_ioctl, + .open = ds1286_open, + .release = ds1286_release, +}; + +static struct miscdevice ds1286_dev= +{ + .minor = RTC_MINOR, + .name = "rtc", + .fops = &ds1286_fops, +}; + +static int __init ds1286_init(void) +{ + int err; + + printk(KERN_INFO "DS1286 Real Time Clock Driver v%s\n", DS1286_VERSION); + + err = misc_register(&ds1286_dev); + if (err) + goto out; + + if (!create_proc_read_entry("driver/rtc", 0, 0, ds1286_read_proc, NULL)) { + err = -ENOMEM; + + goto out_deregister; + } + + return 0; + +out_deregister: + misc_deregister(&ds1286_dev); + +out: + return err; +} + +static void __exit ds1286_exit(void) +{ + remove_proc_entry("driver/rtc", NULL); + misc_deregister(&ds1286_dev); +} + +static char *days[] = { + "***", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" +}; + +/* + * Info exported via "/proc/rtc". + */ +static int ds1286_proc_output(char *buf) +{ + char *p, *s; + struct rtc_time tm; + unsigned char hundredth, month, cmd, amode; + + p = buf; + + ds1286_get_time(&tm); + hundredth = rtc_read(RTC_HUNDREDTH_SECOND); + BCD_TO_BIN(hundredth); + + p += sprintf(p, + "rtc_time\t: %02d:%02d:%02d.%02d\n" + "rtc_date\t: %04d-%02d-%02d\n", + tm.tm_hour, tm.tm_min, tm.tm_sec, hundredth, + tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday); + + /* + * We implicitly assume 24hr mode here. Alarm values >= 0xc0 will + * match any value for that particular field. Values that are + * greater than a valid time, but less than 0xc0 shouldn't appear. + */ + ds1286_get_alm_time(&tm); + p += sprintf(p, "alarm\t\t: %s ", days[tm.tm_wday]); + if (tm.tm_hour <= 24) + p += sprintf(p, "%02d:", tm.tm_hour); + else + p += sprintf(p, "**:"); + + if (tm.tm_min <= 59) + p += sprintf(p, "%02d\n", tm.tm_min); + else + p += sprintf(p, "**\n"); + + month = rtc_read(RTC_MONTH); + p += sprintf(p, + "oscillator\t: %s\n" + "square_wave\t: %s\n", + (month & RTC_EOSC) ? "disabled" : "enabled", + (month & RTC_ESQW) ? "disabled" : "enabled"); + + amode = ((rtc_read(RTC_MINUTES_ALARM) & 0x80) >> 5) | + ((rtc_read(RTC_HOURS_ALARM) & 0x80) >> 6) | + ((rtc_read(RTC_DAY_ALARM) & 0x80) >> 7); + if (amode == 7) s = "each minute"; + else if (amode == 3) s = "minutes match"; + else if (amode == 1) s = "hours and minutes match"; + else if (amode == 0) s = "days, hours and minutes match"; + else s = "invalid"; + p += sprintf(p, "alarm_mode\t: %s\n", s); + + cmd = rtc_read(RTC_CMD); + p += sprintf(p, + "alarm_enable\t: %s\n" + "wdog_alarm\t: %s\n" + "alarm_mask\t: %s\n" + "wdog_alarm_mask\t: %s\n" + "interrupt_mode\t: %s\n" + "INTB_mode\t: %s_active\n" + "interrupt_pins\t: %s\n", + (cmd & RTC_TDF) ? "yes" : "no", + (cmd & RTC_WAF) ? "yes" : "no", + (cmd & RTC_TDM) ? "disabled" : "enabled", + (cmd & RTC_WAM) ? "disabled" : "enabled", + (cmd & RTC_PU_LVL) ? "pulse" : "level", + (cmd & RTC_IBH_LO) ? "low" : "high", + (cmd & RTC_IPSW) ? "unswapped" : "swapped"); + + return p - buf; +} + +static int ds1286_read_proc(char *page, char **start, off_t off, + int count, int *eof, void *data) +{ + int len = ds1286_proc_output (page); + if (len <= off+count) *eof = 1; + *start = page + off; + len -= off; + if (len>count) + len = count; + if (len<0) + len = 0; + + return len; +} + +/* + * Returns true if a clock update is in progress + */ +static inline unsigned char ds1286_is_updating(void) +{ + return rtc_read(RTC_CMD) & RTC_TE; +} + + +static void ds1286_get_time(struct rtc_time *rtc_tm) +{ + unsigned char save_control; + unsigned int flags; + unsigned long uip_watchdog = jiffies; + + /* + * read RTC once any update in progress is done. The update + * can take just over 2ms. We wait 10 to 20ms. There is no need to + * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP. + * If you need to know *exactly* when a second has started, enable + * periodic update complete interrupts, (via ioctl) and then + * immediately read /dev/rtc which will block until you get the IRQ. + * Once the read clears, read the RTC time (again via ioctl). Easy. + */ + + if (ds1286_is_updating() != 0) + while (jiffies - uip_watchdog < 2*HZ/100) + barrier(); + + /* + * Only the values that we read from the RTC are set. We leave + * tm_wday, tm_yday and tm_isdst untouched. Even though the + * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated + * by the RTC when initially set to a non-zero value. + */ + spin_lock_irqsave(&ds1286_lock, flags); + save_control = rtc_read(RTC_CMD); + rtc_write((save_control|RTC_TE), RTC_CMD); + + rtc_tm->tm_sec = rtc_read(RTC_SECONDS); + rtc_tm->tm_min = rtc_read(RTC_MINUTES); + rtc_tm->tm_hour = rtc_read(RTC_HOURS) & 0x3f; + rtc_tm->tm_mday = rtc_read(RTC_DATE); + rtc_tm->tm_mon = rtc_read(RTC_MONTH) & 0x1f; + rtc_tm->tm_year = rtc_read(RTC_YEAR); + + rtc_write(save_control, RTC_CMD); + spin_unlock_irqrestore(&ds1286_lock, flags); + + BCD_TO_BIN(rtc_tm->tm_sec); + BCD_TO_BIN(rtc_tm->tm_min); + BCD_TO_BIN(rtc_tm->tm_hour); + BCD_TO_BIN(rtc_tm->tm_mday); + BCD_TO_BIN(rtc_tm->tm_mon); + BCD_TO_BIN(rtc_tm->tm_year); + + /* + * Account for differences between how the RTC uses the values + * and how they are defined in a struct rtc_time; + */ + if (rtc_tm->tm_year < 45) + rtc_tm->tm_year += 30; + if ((rtc_tm->tm_year += 40) < 70) + rtc_tm->tm_year += 100; + + rtc_tm->tm_mon--; +} + +static int ds1286_set_time(struct rtc_time *rtc_tm) +{ + unsigned char mon, day, hrs, min, sec, leap_yr; + unsigned char save_control; + unsigned int yrs, flags; + + + yrs = rtc_tm->tm_year + 1900; + mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */ + day = rtc_tm->tm_mday; + hrs = rtc_tm->tm_hour; + min = rtc_tm->tm_min; + sec = rtc_tm->tm_sec; + + if (yrs < 1970) + return -EINVAL; + + leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400)); + + if ((mon > 12) || (day == 0)) + return -EINVAL; + + if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr))) + return -EINVAL; + + if ((hrs >= 24) || (min >= 60) || (sec >= 60)) + return -EINVAL; + + if ((yrs -= 1940) > 255) /* They are unsigned */ + return -EINVAL; + + if (yrs >= 100) + yrs -= 100; + + BIN_TO_BCD(sec); + BIN_TO_BCD(min); + BIN_TO_BCD(hrs); + BIN_TO_BCD(day); + BIN_TO_BCD(mon); + BIN_TO_BCD(yrs); + + spin_lock_irqsave(&ds1286_lock, flags); + save_control = rtc_read(RTC_CMD); + rtc_write((save_control|RTC_TE), RTC_CMD); + + rtc_write(yrs, RTC_YEAR); + rtc_write(mon, RTC_MONTH); + rtc_write(day, RTC_DATE); + rtc_write(hrs, RTC_HOURS); + rtc_write(min, RTC_MINUTES); + rtc_write(sec, RTC_SECONDS); + rtc_write(0, RTC_HUNDREDTH_SECOND); + + rtc_write(save_control, RTC_CMD); + spin_unlock_irqrestore(&ds1286_lock, flags); + + return 0; +} + +static void ds1286_get_alm_time(struct rtc_time *alm_tm) +{ + unsigned char cmd; + unsigned int flags; + + /* + * Only the values that we read from the RTC are set. That + * means only tm_wday, tm_hour, tm_min. + */ + spin_lock_irqsave(&ds1286_lock, flags); + alm_tm->tm_min = rtc_read(RTC_MINUTES_ALARM) & 0x7f; + alm_tm->tm_hour = rtc_read(RTC_HOURS_ALARM) & 0x1f; + alm_tm->tm_wday = rtc_read(RTC_DAY_ALARM) & 0x07; + cmd = rtc_read(RTC_CMD); + spin_unlock_irqrestore(&ds1286_lock, flags); + + BCD_TO_BIN(alm_tm->tm_min); + BCD_TO_BIN(alm_tm->tm_hour); + alm_tm->tm_sec = 0; +} + +module_init(ds1286_init); +module_exit(ds1286_exit); + +MODULE_AUTHOR("Ralf Baechle"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(RTC_MINOR); |