rtc: recycle id when unloading a rtc driver

When calling rtc_device_unregister, we are not freeing the id used by the
driver.
So when doing a unload/load cycle for a RTC driver (e.g. rmmod rtc_cmos
&& modprobe rtc_cmos), its id is incremented by one. As a consequence,
we no longer have neither an rtc0 driver nor a /proc/driver/rtc (as it
only exists for the first driver).

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
BUG=None
TEST=on x86 platform, rmmod rtc_cmos && modprobe rtc_cmos
and see the new rtc driver is still /sys/class/rtc/rtc0 and
/proc/driver/rtc still exists.

Change-Id: I1b60e25611d30b46a3744d38dc34213db6e21b72
Reviewed-on: https://gerrit.chromium.org/gerrit/29103
Reviewed-by: Derek Basehore <dbasehore@chromium.org>
Tested-by: Derek Basehore <dbasehore@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Olof Johansson <olofj@chromium.org>
Commit-Ready: Vincent Palatin <vpalatin@chromium.org>

diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index dc4c274..37b1d82 100644 (file)
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -238,6 +238,7 @@ void rtc_device_unregister(struct rtc_device *rtc)
                rtc_proc_del_device(rtc);
                device_unregister(&rtc->dev);
                rtc->ops = NULL;
+               ida_simple_remove(&rtc_ida, rtc->id);
                mutex_unlock(&rtc->ops_lock);
                put_device(&rtc->dev);
        }