projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 0c86edc0 AZ |
1 | /* |
| 2 | * RTC subsystem, initialize system time on startup | |
| 3 | * | |
| 4 | * Copyright (C) 2005 Tower Technologies | |
| 5 | * Author: Alessandro Zummo <[email protected]> | |
| 6 | * | |
| 7 | * This program is free software; you can redistribute it and/or modify | |
| 8 | * it under the terms of the GNU General Public License version 2 as | |
| 9 | * published by the Free Software Foundation. | |
| 10 | */ | |
| 11 | ||
| 12 | #include <linux/rtc.h> | |
| 13 | ||
| 14 | /* IMPORTANT: the RTC only stores whole seconds. It is arbitrary | |
| 15 | * whether it stores the most close value or the value with partial | |
| 16 | * seconds truncated. However, it is important that we use it to store | |
| 17 | * the truncated value. This is because otherwise it is necessary, | |
| 18 | * in an rtc sync function, to read both xtime.tv_sec and | |
| 19 | * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read | |
| 20 | * of >32bits is not possible. So storing the most close value would | |
| 21 | * slow down the sync API. So here we have the truncated value and | |
| 22 | * the best guess is to add 0.5s. | |
| 23 | */ | |
| 24 | ||
| d0ab4a4d UKK |
25 | int rtc_hctosys_ret = -ENODEV; |
| 26 | ||
| 0c86edc0 AZ |
27 | static int __init rtc_hctosys(void) |
| 28 | { | |
| d0ab4a4d | 29 | int err = -ENODEV; |
| 0c86edc0 | 30 | struct rtc_time tm; |
| d0ab4a4d UKK |
31 | struct timespec tv = { |
| 32 | .tv_nsec = NSEC_PER_SEC >> 1, | |
| 33 | }; | |
| ab6a2d70 | 34 | struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE); |
| 0c86edc0 | 35 | |
| ab6a2d70 | 36 | if (rtc == NULL) { |
| d0ab4a4d | 37 | pr_err("%s: unable to open rtc device (%s)\n", |
| 0c86edc0 | 38 | __FILE__, CONFIG_RTC_HCTOSYS_DEVICE); |
| d0ab4a4d | 39 | goto err_open; |
| 0c86edc0 AZ |
40 | } |
| 41 | ||
| ab6a2d70 | 42 | err = rtc_read_time(rtc, &tm); |
| d0ab4a4d UKK |
43 | if (err) { |
| 44 | dev_err(rtc->dev.parent, | |
| 45 | "hctosys: unable to read the hardware clock\n"); | |
| 46 | goto err_read; | |
| 0c86edc0 | 47 | |
| d0ab4a4d | 48 | } |
| 0c86edc0 | 49 | |
| d0ab4a4d UKK |
50 | err = rtc_valid_tm(&tm); |
| 51 | if (err) { | |
| 52 | dev_err(rtc->dev.parent, | |
| 53 | "hctosys: invalid date/time\n"); | |
| 54 | goto err_invalid; | |
| 55 | } | |
| 0c86edc0 | 56 | |
| d0ab4a4d | 57 | rtc_tm_to_time(&tm, &tv.tv_sec); |
| 0c86edc0 | 58 | |
| d0ab4a4d | 59 | do_settimeofday(&tv); |
| 0c86edc0 | 60 | |
| d0ab4a4d UKK |
61 | dev_info(rtc->dev.parent, |
| 62 | "setting system clock to " | |
| 63 | "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n", | |
| 64 | tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, | |
| 65 | tm.tm_hour, tm.tm_min, tm.tm_sec, | |
| 66 | (unsigned int) tv.tv_sec); | |
| 67 | ||
| 68 | err_invalid: | |
| 69 | err_read: | |
| ab6a2d70 | 70 | rtc_class_close(rtc); |
| 0c86edc0 | 71 | |
| d0ab4a4d UKK |
72 | err_open: |
| 73 | rtc_hctosys_ret = err; | |
| 74 | ||
| 75 | return err; | |
| 0c86edc0 AZ |
76 | } |
| 77 | ||
| 78 | late_initcall(rtc_hctosys); |