alarmtimer: Make alarmtimer platform device child of RTC device (c79108bd) · Commits · 戴 / test

The alarmtimer_suspend() function will fail if an RTC device is on a bus such as SPI or i2c and that RTC device registers and probes after alarmtimer_init() registers and probes the 'alarmtimer' platform device. This is because system wide suspend suspends devices in the reverse order of their probe. When alarmtimer_suspend() attempts to program the RTC for a wakeup it will try to program an RTC device on a bus that has already been suspended. Move the alarmtimer device registration to happen when the RTC which is used for wakeup is registered. Register the 'alarmtimer' platform device as a child of the RTC device too, so that it can be guaranteed that the RTC device won't be suspended when alarmtimer_suspend() is called. Reported-by:

Douglas Anderson <dianders@chromium.org> Signed-off-by:

Stephen Boyd <swboyd@chromium.org> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> Reviewed-by:

Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200124055849.154411-2-swboyd@chromium.org

kernel/time/alarmtimer.c

+9 −11

Original line number	Diff line number	Diff line
		@@ -89,6 +89,7 @@ static int alarmtimer_rtc_add_device(struct device *dev,
		unsigned long flags;
		struct rtc_device *rtc = to_rtc_device(dev);
		struct wakeup_source *__ws;
		struct platform_device *pdev;
		int ret = 0;

		if (rtcdev)
		@@ -100,9 +101,11 @@ static int alarmtimer_rtc_add_device(struct device *dev,
		return -1;

		__ws = wakeup_source_register(dev, "alarmtimer");
		pdev = platform_device_register_data(dev, "alarmtimer",
		PLATFORM_DEVID_AUTO, NULL, 0);

		spin_lock_irqsave(&rtcdev_lock, flags);
		if (!rtcdev) {
		if (__ws && !IS_ERR(pdev) && !rtcdev) {
		if (!try_module_get(rtc->owner)) {
		ret = -1;
		goto unlock;
		@@ -113,10 +116,14 @@ static int alarmtimer_rtc_add_device(struct device *dev,
		get_device(dev);
		ws = __ws;
		__ws = NULL;
		pdev = NULL;
		} else {
		ret = -1;
		}
		unlock:
		spin_unlock_irqrestore(&rtcdev_lock, flags);

		platform_device_unregister(pdev);
		wakeup_source_unregister(__ws);

		return ret;
		@@ -903,8 +910,7 @@ static void get_boottime_timespec(struct timespec64 *tp)
		*/
		static int __init alarmtimer_init(void)
		{
		struct platform_device *pdev;
		int error = 0;
		int error;
		int i;

		alarmtimer_rtc_timer_init();
		@@ -929,15 +935,7 @@ static int __init alarmtimer_init(void)
		if (error)
		goto out_if;

		pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
		if (IS_ERR(pdev)) {
		error = PTR_ERR(pdev);
		goto out_drv;
		}
		return 0;

		out_drv:
		platform_driver_unregister(&alarmtimer_driver);
		out_if:
		alarmtimer_rtc_interface_remove();
		return error;

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