rtc: add basic support for ST M41T93 SPI RTC

Add basic support for ST m41t93 SPI RTCs.  Tested with factory-new and
with "run-in" species with and without backup batteries.

Signed-off-by: Nikolaus Voss <n.voss@weinmann.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 4956e416b315..0a69ed9fb454 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -385,6 +385,15 @@ comment "SPI RTC drivers"
 
 if SPI_MASTER
 
+config RTC_DRV_M41T93
+        tristate "ST M41T93"
+        help
+          If you say yes here you will get support for the
+          ST M41T93 SPI RTC chip.
+
+          This driver can also be built as a module. If so, the module
+          will be called rtc-m41t93.
+
 config RTC_DRV_M41T94
         tristate "ST M41T94"
         help