this is powered by the backup power supply.
config RTC_DRV_AT91SAM9
- tristate "AT91SAM9x/AT91CAP9 RTT as RTC"
+ tristate "AT91SAM9 RTT as RTC"
- depends on ARCH_AT91 && !(ARCH_AT91RM9200 || ARCH_AT91X40)
+ depends on ARCH_AT91 && !ARCH_AT91RM9200
+ select MFD_SYSCON
help
- RTC driver for the Atmel AT91SAM9x and AT91CAP9 internal RTT
- (Real Time Timer). These timers are powered by the backup power
- supply (such as a small coin cell battery), but do not need to
- be used as RTCs.
-
- (On AT91SAM9rl and AT91SAM9G45 chips you probably want to use the
- dedicated RTC module and leave the RTT available for other uses.)
+ Some AT91SAM9 SoCs provide an RTT (Real Time Timer) block which
+ can be used as an RTC thanks to the backup power supply (e.g. a
+ small coin cell battery) which keeps this block and the GPBR
+ (General Purpose Backup Registers) block powered when the device
+ is shutdown.
+ Some AT91SAM9 SoCs provide a real RTC block, on those ones you'd
+ probably want to use the real RTC block instead of the "RTT as an
+ RTC" driver.
config RTC_DRV_AT91SAM9_RTT
int