| Message ID | 14cc1b9c-66af-2e09-1ca5-07aa55025beb@gmail.com |
|---|---|
| State | Rejected |
| Headers | show |
Am 07.03.2017 um 20:10 schrieb Heiner Kallweit: > It's a little annoying that rtc driver plus all drivers it depends on > (e.g. I2C) have to be compiled into the kernel to be used with hctosys. > > I think it would be more logical to set the system clock once the > rtc driver has been registered. Therefore move the hctosys > functionality to the end of rtc_device_register. > > Works perfectly fine here. > Do you have an opinion on this one? Rgds, Heiner > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> > --- > drivers/rtc/Makefile | 1 - > drivers/rtc/class.c | 38 ++++++++++++++++++++++++++++ > drivers/rtc/hctosys.c | 70 --------------------------------------------------- > 3 files changed, 38 insertions(+), 71 deletions(-) > delete mode 100644 drivers/rtc/hctosys.c > > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile > index f07297b1..f1d57b06 100644 > --- a/drivers/rtc/Makefile > +++ b/drivers/rtc/Makefile > @@ -5,7 +5,6 @@ > ccflags-$(CONFIG_RTC_DEBUG) := -DDEBUG > > obj-$(CONFIG_RTC_LIB) += rtc-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 74fd9746..dcfd2e64 100644 > --- a/drivers/rtc/class.c > +++ b/drivers/rtc/class.c > @@ -168,6 +168,13 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, > struct rtc_wkalrm alrm; > int of_id = -1, id = -1, err; > > +#if IS_ENABLED(CONFIG_RTC_HCTOSYS) > + struct rtc_time tm; > + struct timespec64 tv64 = { > + .tv_nsec = NSEC_PER_SEC >> 1, > + }; > +#endif > + > if (dev->of_node) > of_id = of_alias_get_id(dev->of_node, "rtc"); > else if (dev->parent && dev->parent->of_node) > @@ -246,6 +253,37 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, > dev_info(dev, "rtc core: registered %s as %s\n", > rtc->name, dev_name(&rtc->dev)); > > +#if IS_ENABLED(CONFIG_RTC_HCTOSYS) > +/* 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. > + */ > + if (!strcmp(CONFIG_RTC_HCTOSYS_DEVICE, dev_name(&rtc->dev))) { > + err = rtc_read_time(rtc, &tm); > + if (err) { > + dev_err(dev, "hctosys: unable to read the hardware clock\n"); > + goto hctosys_out; > + } > + > + tv64.tv_sec = rtc_tm_to_time64(&tm); > + > + err = do_settimeofday64(&tv64); > + > + dev_info(dev, "setting system clock to %d-%02d-%02d %02d:%02d:%02d UTC (%lld)\n", > + tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, > + tm.tm_hour, tm.tm_min, tm.tm_sec, > + (long long) tv64.tv_sec); > +hctosys_out: > + rtc_hctosys_ret = err; > + } > +#endif > + > return rtc; > > exit_ida: > diff --git a/drivers/rtc/hctosys.c b/drivers/rtc/hctosys.c > deleted file mode 100644 > index e1cfa068..00000000 > --- a/drivers/rtc/hctosys.c > +++ /dev/null > @@ -1,70 +0,0 @@ > -/* > - * 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. > -*/ > - > -#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 == NULL) { > - 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); > - > - err = do_settimeofday64(&tv64); > - > - dev_info(rtc->dev.parent, > - "setting system clock to " > - "%d-%02d-%02d %02d:%02d:%02d UTC (%lld)\n", > - tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, > - tm.tm_hour, tm.tm_min, tm.tm_sec, > - (long long) tv64.tv_sec); > - > -err_read: > - rtc_class_close(rtc); > - > -err_open: > - rtc_hctosys_ret = err; > - > - return err; > -} > - > -late_initcall(rtc_hctosys); >
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index f07297b1..f1d57b06 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -5,7 +5,6 @@ ccflags-$(CONFIG_RTC_DEBUG) := -DDEBUG obj-$(CONFIG_RTC_LIB) += rtc-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 74fd9746..dcfd2e64 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -168,6 +168,13 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, struct rtc_wkalrm alrm; int of_id = -1, id = -1, err; +#if IS_ENABLED(CONFIG_RTC_HCTOSYS) + struct rtc_time tm; + struct timespec64 tv64 = { + .tv_nsec = NSEC_PER_SEC >> 1, + }; +#endif + if (dev->of_node) of_id = of_alias_get_id(dev->of_node, "rtc"); else if (dev->parent && dev->parent->of_node) @@ -246,6 +253,37 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, dev_info(dev, "rtc core: registered %s as %s\n", rtc->name, dev_name(&rtc->dev)); +#if IS_ENABLED(CONFIG_RTC_HCTOSYS) +/* 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. + */ + if (!strcmp(CONFIG_RTC_HCTOSYS_DEVICE, dev_name(&rtc->dev))) { + err = rtc_read_time(rtc, &tm); + if (err) { + dev_err(dev, "hctosys: unable to read the hardware clock\n"); + goto hctosys_out; + } + + tv64.tv_sec = rtc_tm_to_time64(&tm); + + err = do_settimeofday64(&tv64); + + dev_info(dev, "setting system clock to %d-%02d-%02d %02d:%02d:%02d UTC (%lld)\n", + tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, + tm.tm_hour, tm.tm_min, tm.tm_sec, + (long long) tv64.tv_sec); +hctosys_out: + rtc_hctosys_ret = err; + } +#endif + return rtc; exit_ida: diff --git a/drivers/rtc/hctosys.c b/drivers/rtc/hctosys.c deleted file mode 100644 index e1cfa068..00000000 --- a/drivers/rtc/hctosys.c +++ /dev/null @@ -1,70 +0,0 @@ -/* - * 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. -*/ - -#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 == NULL) { - 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); - - err = do_settimeofday64(&tv64); - - dev_info(rtc->dev.parent, - "setting system clock to " - "%d-%02d-%02d %02d:%02d:%02d UTC (%lld)\n", - tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, - tm.tm_hour, tm.tm_min, tm.tm_sec, - (long long) tv64.tv_sec); - -err_read: - rtc_class_close(rtc); - -err_open: - rtc_hctosys_ret = err; - - return err; -} - -late_initcall(rtc_hctosys);
It's a little annoying that rtc driver plus all drivers it depends on (e.g. I2C) have to be compiled into the kernel to be used with hctosys. I think it would be more logical to set the system clock once the rtc driver has been registered. Therefore move the hctosys functionality to the end of rtc_device_register. Works perfectly fine here. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> --- drivers/rtc/Makefile | 1 - drivers/rtc/class.c | 38 ++++++++++++++++++++++++++++ drivers/rtc/hctosys.c | 70 --------------------------------------------------- 3 files changed, 38 insertions(+), 71 deletions(-) delete mode 100644 drivers/rtc/hctosys.c