[PATCH] rtc: bd70528: fix link error

[Arnd Bergmann]

With CONFIG_BD70528_WATCHDOG=m, a built-in rtc driver cannot call
into the low-level functions that are part of the watchdog module:

drivers/rtc/rtc-bd70528.o: In function `bd70528_set_time':
rtc-bd70528.c:(.text+0x22c): undefined reference to `bd70528_wdt_lock'
rtc-bd70528.c:(.text+0x2a8): undefined reference to `bd70528_wdt_unlock'
drivers/rtc/rtc-bd70528.o: In function `bd70528_set_rtc_based_timers':
rtc-bd70528.c:(.text+0x50c): undefined reference to `bd70528_wdt_set'

Add a Kconfig dependency on this driver, but still allow compile-testing
without it.

Fixes: 32a4a4ebf768 ("rtc: bd70528: Initial support for ROHM bd70528 RTC")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 drivers/rtc/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 3bfc04a86529..7b071cc74422 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -498,8 +498,10 @@ config RTC_DRV_M41T80_WDT
 	help
 	  If you say Y here you will get support for the
 	  watchdog timer in the ST M41T60 and M41T80 RTC chips series.
+
 config RTC_DRV_BD70528
 	tristate "ROHM BD70528 PMIC RTC"
+	depends on BD70528_WATCHDOG || (COMPILE_TEST && !BD70528_WATCHDOG)
 	help
 	  If you say Y here you will get support for the RTC
 	  on ROHM BD70528 Power Management IC.
-- 
2.20.0