panasonic-laptop: add Panasonic Let's Note laptop extras driver v0.94

This is a driver for ACPI extras such as hotkeys and backlight
brightness control on various Panasonic "Let's Note" series laptop
computers.

It exports the backlight via the backlight class device API,
and the hotkeys as input event device.  Some more esoteric
items like number of installed batteries are exported via sysfs
device attributes.

Hotkey events also generate old-style ACPI enents through
/proc/acpi/event to interoperate with current versions of acpid.

Signed-off-by: Harald Welte <laforge@gnumonks.org>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

MAINTAINERS

@@ -3148,6 +3148,11 @@ M:	olof@lixom.net
 L:	i2c@lm-sensors.org
 S:	Maintained
 
+PANASONIC LAPTOP ACPI EXTRAS DRIVER
+P:	Harald Welte
+M:	laforge@gnumonks.org
+S:	Maintained
+
 PARALLEL PORT SUPPORT
 L:	linux-parport@lists.infradead.org (subscribers-only)
 S:	Orphan

drivers/misc/Kconfig

@@ -245,6 +245,17 @@ config MSI_LAPTOP
 
 	  If you have an MSI S270 laptop, say Y or M here.
 
+config PANASONIC_LAPTOP
+	tristate "Panasonic Laptop Extras"
+	depends on X86 && INPUT
+        depends on BACKLIGHT_CLASS_DEVICE
+	---help---
+	  This driver adds support for access to backlight control and hotkeys
+	  on Panasonic Let's Note laptops.
+
+	  If you have a Panasonic Let's note laptop (such as the R1(N variant),
+	  R2, R3, R5, T2, W2 and Y2 series), say Y.
+
 config COMPAL_LAPTOP
 	tristate "Compal Laptop Extras"
 	depends on X86

drivers/misc/Makefile

@@ -23,6 +23,7 @@ obj-$(CONFIG_SGI_IOC4)		+= ioc4.o
 obj-$(CONFIG_SONY_LAPTOP)	+= sony-laptop.o
 obj-$(CONFIG_THINKPAD_ACPI)	+= thinkpad_acpi.o
 obj-$(CONFIG_FUJITSU_LAPTOP)	+= fujitsu-laptop.o
+obj-$(CONFIG_PANASONIC_LAPTOP)	+= panasonic-laptop.o
 obj-$(CONFIG_EEPROM_93CX6)	+= eeprom_93cx6.o
 obj-$(CONFIG_INTEL_MENLOW)	+= intel_menlow.o
 obj-$(CONFIG_ENCLOSURE_SERVICES) += enclosure.o