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authorSteve Muckle <smuckle@google.com>2019-11-06 22:46:25 +0300
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2020-03-23 23:14:34 +0300
commitf9b2a4d6a5f18e0aaf715206a056565c56889d9f (patch)
treebdeca920791915a229977f6b345d2729f7fc0b24 /drivers/rtc/hctosys.c
parent34ce29774dadc24ac1a529c562c325db2b77c7b4 (diff)
downloadlinux-f9b2a4d6a5f18e0aaf715206a056565c56889d9f.tar.xz
rtc: class: support hctosys from modular RTC drivers
Due to distribution constraints it may not be possible to statically compile the required RTC driver into the kernel. Expand RTC_HCTOSYS support to cover all RTC devices (statically compiled or not) by checking at the end of RTC device registration whether the time should be synced. Signed-off-by: Steve Muckle <smuckle@google.com> Link: https://lore.kernel.org/r/20191106194625.116692-1-smuckle@google.com Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'drivers/rtc/hctosys.c')
-rw-r--r--drivers/rtc/hctosys.c69
1 files changed, 0 insertions, 69 deletions
diff --git a/drivers/rtc/hctosys.c b/drivers/rtc/hctosys.c
deleted file mode 100644
index a74d0d890600..000000000000
--- a/drivers/rtc/hctosys.c
+++ /dev/null
@@ -1,69 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * RTC subsystem, initialize system time on startup
- *
- * Copyright (C) 2005 Tower Technologies
- * Author: Alessandro Zummo <a.zummo@towertech.it>
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#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.
- */
-
-static int __init rtc_hctosys(void)
-{
- int err = -ENODEV;
- struct rtc_time tm;
- struct timespec64 tv64 = {
- .tv_nsec = NSEC_PER_SEC >> 1,
- };
- struct rtc_device *rtc = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
-
- if (!rtc) {
- pr_info("unable to open rtc device (%s)\n",
- 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;
- }
-
- tv64.tv_sec = rtc_tm_to_time64(&tm);
-
-#if BITS_PER_LONG == 32
- if (tv64.tv_sec > INT_MAX) {
- err = -ERANGE;
- goto err_read;
- }
-#endif
-
- err = do_settimeofday64(&tv64);
-
- dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n",
- &tm, (long long)tv64.tv_sec);
-
-err_read:
- rtc_class_close(rtc);
-
-err_open:
- rtc_hctosys_ret = err;
-
- return err;
-}
-
-late_initcall(rtc_hctosys);