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@xxxxxxxxx>
> ---
> 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@xxxxxxxxxxxx>
> - *
> - * 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);
>
