drivers/rtc/rtc-r9701.c: fix crash in r9701_remove()
If probing the RTC didn't succeed due to failed RTC register access, the
RTC device will be unregistered. Then, when removing the module
r9701_remove() causes a kernel crash while trying to unregister a not
registered RTC device. Fix this by doing RTC register access test before
RTC device registration.
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/rtc-r9701.c b/drivers/rtc/rtc-r9701.c
index 9beba49c..2853c2a 100644
--- a/drivers/rtc/rtc-r9701.c
+++ b/drivers/rtc/rtc-r9701.c
@@ -125,6 +125,13 @@
unsigned char tmp;
int res;
+ tmp = R100CNT;
+ res = read_regs(&spi->dev, &tmp, 1);
+ if (res || tmp != 0x20) {
+ dev_err(&spi->dev, "cannot read RTC register\n");
+ return -ENODEV;
+ }
+
rtc = rtc_device_register("r9701",
&spi->dev, &r9701_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
@@ -132,13 +139,6 @@
dev_set_drvdata(&spi->dev, rtc);
- tmp = R100CNT;
- res = read_regs(&spi->dev, &tmp, 1);
- if (res || tmp != 0x20) {
- rtc_device_unregister(rtc);
- return res;
- }
-
return 0;
}