cs5535: add a generic MFGPT driver

This is based on the old code on arch/x86/kernel/mfgpt_32.c, except it's
not x86 specific, it's modular, and it makes use of a PCI BAR rather than
a random MSR.  Currently module unloading is not supported; it's uncertain
whether or not it can be made work with the hardware.

[akpm@linux-foundation.org: add X86 dependency]
Signed-off-by: Andres Salomon <dilinger@collabora.co.uk>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Chris Ball <cjb@laptop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 724d1188a322..d6d6d846f0d6 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -187,6 +187,30 @@ config SGI_XP
           this feature will allow for direct communication between SSIs
           based on a network adapter and DMA messaging.
 
+config CS5535_MFGPT
+        tristate "CS5535/CS5536 Geode Multi-Function General Purpose Timer (MFGPT) support"
+        depends on PCI && !MGEODE_LX
+        depends on X86
+        default n
+        help
+          This driver provides access to MFGPT functionality for other
+          drivers that need timers.  MFGPTs are available in the CS5535 and
+          CS5536 companion chips that are found in AMD Geode and several
+          other platforms.  They have a better resolution and max interval
+          than the generic PIT, and are suitable for use as high-res timers.
+          You probably don't want to enable this manually; other drivers that
+          make use of it should enable it.
+
+config CS5535_MFGPT_DEFAULT_IRQ
+        int
+        default 7
+        help
+          MFGPTs on the CS5535 require an interrupt.  The selected IRQ
+          can be overridden as a module option as well as by driver that
+          use the cs5535_mfgpt_ API; however, different architectures might
+          want to use a different IRQ by default.  This is here for
+          architectures to set as necessary.
+
 config HP_ILO
         tristate "Channel interface driver for HP iLO/iLO2 processor"
         depends on PCI