RTC: Revert UIE emulation removal

Uwe pointed out that my alarm based UIE emulation is not sufficient
to replace the older timer/polling based UIE emulation on devices
where there is no alarm irq. This causes rtc devices without alarms
to return -EINVAL to UIE ioctls. The fix is to re-instate the old
timer/polling method for devices without alarm irqs.

This patch reverts the following commits:
042620a018 - Remove UIE emulation
1daeddd596 - Cleanup removed UIE emulation declaration
b5cc8ca1c9 - Remove Kconfig symbol for UIE emulation

The emulation mode will still need to be wired-in with a following
patch before it will work.

CC: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
CC: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
John Stultz
2011-02-11 17:45:40 -08:00
parent 516373b8b6
commit 6e57b1d6a8
3 changed files with 130 additions and 0 deletions

View File

@@ -97,6 +97,18 @@ config RTC_INTF_DEV
If unsure, say Y.
config RTC_INTF_DEV_UIE_EMUL
bool "RTC UIE emulation on dev interface"
depends on RTC_INTF_DEV
help
Provides an emulation for RTC_UIE if the underlying rtc chip
driver does not expose RTC_UIE ioctls. Those requests generate
once-per-second update interrupts, used for synchronization.
The emulation code will read the time from the hardware
clock several times per second, please enable this option
only if you know that you really need it.
config RTC_DRV_TEST
tristate "Test driver/device"
help