diff options
| -rw-r--r-- | drivers/rtc/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/rtc/Makefile | 1 | ||||
| -rw-r--r-- | drivers/rtc/class.c | 61 | ||||
| -rw-r--r-- | drivers/rtc/hctosys.c | 69 |
4 files changed, 61 insertions, 73 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index 6c99156cbe57..417fc6ec9338 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -41,9 +41,6 @@ config RTC_HCTOSYS_DEVICE device should record time in UTC, since the kernel won't do timezone correction. - The driver for this RTC device must be loaded before late_initcall - functions run, so it must usually be statically linked. - This clock should be battery-backed, so that it reads the correct time when the system boots from a power-off state. Otherwise, your system will need an external clock source (like an NTP server). diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index 6c3e93aa36dc..8642d6f7560d 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -6,7 +6,6 @@ ccflags-$(CONFIG_RTC_DEBUG) := -DDEBUG obj-$(CONFIG_RTC_LIB) += lib.o -obj-$(CONFIG_RTC_HCTOSYS) += hctosys.o obj-$(CONFIG_RTC_SYSTOHC) += systohc.o obj-$(CONFIG_RTC_CLASS) += rtc-core.o obj-$(CONFIG_RTC_MC146818_LIB) += rtc-mc146818-lib.o diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 9458e6d6686a..8793b2b8cf9d 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -34,6 +34,62 @@ static void rtc_device_release(struct device *dev) #ifdef CONFIG_RTC_HCTOSYS_DEVICE /* Result of the last RTC to system clock attempt. */ int rtc_hctosys_ret = -ENODEV; + +/* 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 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; +} #endif #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE) @@ -375,6 +431,11 @@ int __rtc_register_device(struct module *owner, struct rtc_device *rtc) dev_info(rtc->dev.parent, "registered as %s\n", dev_name(&rtc->dev)); +#ifdef CONFIG_RTC_HCTOSYS_DEVICE + if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE)) + rtc_hctosys(); +#endif + return 0; } EXPORT_SYMBOL_GPL(__rtc_register_device); 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); |