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author | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
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committer | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
commit | 871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch) | |
tree | 8718f573808810c2a1e8cb8fb6ac469093ca2784 /drivers/rtc/hctosys.c | |
parent | 9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff) | |
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Moved, renamed, and deleted files
The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
Diffstat (limited to 'drivers/rtc/hctosys.c')
-rw-r--r-- | drivers/rtc/hctosys.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/drivers/rtc/hctosys.c b/drivers/rtc/hctosys.c new file mode 100644 index 00000000..bc90b091 --- /dev/null +++ b/drivers/rtc/hctosys.c @@ -0,0 +1,78 @@ +/* + * RTC subsystem, initialize system time on startup + * + * Copyright (C) 2005 Tower Technologies + * Author: Alessandro Zummo <a.zummo@towertech.it> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. +*/ + +#include <linux/rtc.h> + +/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary + * whether it stores the most close value or the value with partial + * seconds truncated. However, it is important that we use it to store + * the truncated value. This is because otherwise it is necessary, + * in an rtc sync function, to read both xtime.tv_sec and + * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read + * of >32bits is not possible. So storing the most close value would + * slow down the sync API. So here we have the truncated value and + * the best guess is to add 0.5s. + */ + +int rtc_hctosys_ret = -ENODEV; + +static int __init rtc_hctosys(void) +{ + int err = -ENODEV; + struct rtc_time tm; + struct timespec tv = { + .tv_nsec = NSEC_PER_SEC >> 1, + }; + struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE); + + if (rtc == NULL) { + pr_err("%s: unable to open rtc device (%s)\n", + __FILE__, CONFIG_RTC_HCTOSYS_DEVICE); + goto err_open; + } + + err = rtc_read_time(rtc, &tm); + if (err) { + dev_err(rtc->dev.parent, + "hctosys: unable to read the hardware clock\n"); + goto err_read; + + } + + err = rtc_valid_tm(&tm); + if (err) { + dev_err(rtc->dev.parent, + "hctosys: invalid date/time\n"); + goto err_invalid; + } + + rtc_tm_to_time(&tm, &tv.tv_sec); + + do_settimeofday(&tv); + + dev_info(rtc->dev.parent, + "setting system clock to " + "%d-%02d-%02d %02d:%02d:%02d UTC (%u)\n", + tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, + tm.tm_hour, tm.tm_min, tm.tm_sec, + (unsigned int) tv.tv_sec); + +err_invalid: +err_read: + rtc_class_close(rtc); + +err_open: + rtc_hctosys_ret = err; + + return err; +} + +late_initcall(rtc_hctosys); |