rtc: add driver for DS1685 family of real time clocks
This adds a driver for the Dallas/Maxim DS1685-family of RTC chips. It
supports the DS1685/DS1687, DS1688/DS1691, DS1689/DS1693, DS17285/DS17287,
DS17485/DS17487, and DS17885/DS17887 RTC chips. These chips are commonly
found in SGI O2 and SGI Octane systems. It was originally derived from a
driver patch submitted by Matthias Fuchs many years ago for use in
EPPC-405-UC modules, which also used these RTCs. In addition to the
time-keeping functions, this RTC also handles the shutdown mechanism of
the O2 and Octane and acts as a partial NVRAM for the boot PROMS in these
systems.
Verified on both an SGI O2 and an SGI Octane.
Signed-off-by: Joshua Kinard <kumba@gentoo.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
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/Kconfig b/drivers/rtc/Kconfig
index 3bc9ddb..0cf2e1d 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -801,6 +801,96 @@
This driver can also be built as a module. If so, the module
will be called rtc-ds1553.
+config RTC_DRV_DS1685_FAMILY
+ tristate "Dallas/Maxim DS1685 Family"
+ help
+ If you say yes here you get support for the Dallas/Maxim DS1685
+ family of real time chips. This family includes the DS1685/DS1687,
+ DS1689/DS1693, DS17285/DS17287, DS17485/DS17487, and
+ DS17885/DS17887 chips.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-ds1685.
+
+choice
+ prompt "Subtype"
+ depends on RTC_DRV_DS1685_FAMILY
+ default RTC_DRV_DS1685
+
+config RTC_DRV_DS1685
+ bool "DS1685/DS1687"
+ help
+ This enables support for the Dallas/Maxim DS1685/DS1687 real time
+ clock chip.
+
+ This chip is commonly found in SGI O2 (IP32) and SGI Octane (IP30)
+ systems, as well as EPPC-405-UC modules by electronic system design
+ GmbH.
+
+config RTC_DRV_DS1689
+ bool "DS1689/DS1693"
+ help
+ This enables support for the Dallas/Maxim DS1689/DS1693 real time
+ clock chip.
+
+ This is an older RTC chip, supplanted by the DS1685/DS1687 above,
+ which supports a few minor features such as Vcc, Vbat, and Power
+ Cycle counters, plus a customer-specific, 8-byte ROM/Serial number.
+
+ It also works for the even older DS1688/DS1691 RTC chips, which are
+ virtually the same and carry the same model number. Both chips
+ have 114 bytes of user NVRAM.
+
+config RTC_DRV_DS17285
+ bool "DS17285/DS17287"
+ help
+ This enables support for the Dallas/Maxim DS17285/DS17287 real time
+ clock chip.
+
+ This chip features 2kb of extended NV-SRAM. It may possibly be
+ found in some SGI O2 systems (rare).
+
+config RTC_DRV_DS17485
+ bool "DS17485/DS17487"
+ help
+ This enables support for the Dallas/Maxim DS17485/DS17487 real time
+ clock chip.
+
+ This chip features 4kb of extended NV-SRAM.
+
+config RTC_DRV_DS17885
+ bool "DS17885/DS17887"
+ help
+ This enables support for the Dallas/Maxim DS17885/DS17887 real time
+ clock chip.
+
+ This chip features 8kb of extended NV-SRAM.
+
+endchoice
+
+config RTC_DS1685_PROC_REGS
+ bool "Display register values in /proc"
+ depends on RTC_DRV_DS1685_FAMILY && PROC_FS
+ help
+ Enable this to display a readout of all of the RTC registers in
+ /proc/drivers/rtc. Keep in mind that this can potentially lead
+ to lost interrupts, as reading Control Register C will clear
+ all pending IRQ flags.
+
+ Unless you are debugging this driver, choose N.
+
+config RTC_DS1685_SYSFS_REGS
+ bool "SysFS access to RTC register bits"
+ depends on RTC_DRV_DS1685_FAMILY && SYSFS
+ help
+ Enable this to provide access to the RTC control register bits
+ in /sys. Some of the bits are read-write, others are read-only.
+
+ Keep in mind that reading Control C's bits automatically clears
+ all pending IRQ flags - this can cause lost interrupts.
+
+ If you know that you need access to these bits, choose Y, Else N.
+
config RTC_DRV_DS1742
tristate "Maxim/Dallas DS1742/1743"
depends on HAS_IOMEM