[PATCH 5.4 291/344] alarmtimer: Make alarmtimer platform device child of RTC device

Greg Kroah-Hartman
2020-02-21T08:31:19Z

From: Stephen Boyd <swboyd@chromium.org>

[ Upstream commit c79108bd19a8490315847e0c95ac6526fcd8e770 ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/time/alarmtimer.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 4b11f0309eee4..b97401f6bc232 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -88,6 +88,7 @@ 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)
@@ -99,9 +100,11 @@ 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;
@@ -112,10 +115,14 @@ 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;
@@ -876,8 +883,7 @@ static struct platform_driver alarmtimer_driver = {
*/
static int __init alarmtimer_init(void)
{
- struct platform_device *pdev;
- int error = 0;
+ int error;
int i;

alarmtimer_rtc_timer_init();
@@ -900,15 +906,7 @@ 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;
--
2.20.1