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alarmtimer: Make alarmtimer platform device child of RTC device 

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
This commit is contained in:
Stephen Boyd 2020-01-23 21:58:46 -08:00 committed by Thomas Gleixner
parent 6b088cefbe
commit c79108bd19
1 changed files with 9 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
kernel/time/alarmtimer.c
View File

@ -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;