ACPI: Add CMOS RTC Operation Region handler support

On HP Folio 13-2000, the BIOS defines a CMOS RTC Operation Region and
the EC's _REG methord accesses that region.  Thus an appropriate
address space handler must be registered for that region before the
EC driver is loaded.

Introduce a mechanism for adding CMOS RTC address space handlers.
Register an ACPI scan handler for CMOS RTC devices such that, when
a device of that kind is detected during an ACPI namespace scan, a
common CMOS RTC operation region address space handler will be
installed for it.

References: https://bugzilla.kernel.org/show_bug.cgi?id=54621
Reported-and-tested-by: Stefan Nagy <public@stefan-nagy.at>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Cc: 3.9+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index b14ac46948c9..a514be216440 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2040,6 +2040,7 @@ int __init acpi_scan_init(void)
 	acpi_pci_link_init();
 	acpi_platform_init();
 	acpi_lpss_init();
+	acpi_cmos_rtc_init();
 	acpi_container_init();
 	acpi_memory_hotplug_init();