Platform: OLPC: Add XO-1.75 EC driver

It's based off the driver from the OLPC kernel sources. Somewhat
modernized and cleaned up, for better or worse.

Modified to plug into the olpc-ec driver infrastructure (so that battery
interface and debugfs could be reused) and the SPI slave framework.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

arch/x86/Kconfig

@@ -2698,6 +2698,7 @@ config OLPC
 	select OF
 	select OF_PROMTREE
 	select IRQ_DOMAIN
+	select OLPC_EC
 	---help---
 	  Add support for detecting the unique features of the OLPC
 	  XO hardware.

drivers/platform/Kconfig

@@ -10,3 +10,5 @@ source "drivers/platform/goldfish/Kconfig"
 source "drivers/platform/chrome/Kconfig"
 
 source "drivers/platform/mellanox/Kconfig"
+
+source "drivers/platform/olpc/Kconfig"

drivers/platform/Makefile

@@ -6,6 +6,6 @@
 obj-$(CONFIG_X86)		+= x86/
 obj-$(CONFIG_MELLANOX_PLATFORM)	+= mellanox/
 obj-$(CONFIG_MIPS)		+= mips/
-obj-$(CONFIG_OLPC)		+= olpc/
+obj-$(CONFIG_OLPC_EC)		+= olpc/
 obj-$(CONFIG_GOLDFISH)		+= goldfish/
 obj-$(CONFIG_CHROME_PLATFORMS)	+= chrome/

drivers/platform/olpc/Kconfig

@@ -0,0 +1,14 @@
+config OLPC_EC
+	bool
+
+config OLPC_XO175_EC
+	tristate "OLPC XO 1.75 Embedded Controller"
+	depends on ARCH_MMP || COMPILE_TEST
+	select SPI_SLAVE
+	select OLPC_EC
+	help
+	  Include support for the OLPC XO Embedded Controller (EC). The EC
+	  provides various platform services, including support for the power,
+	  button, restart, shutdown and battery charging status.
+
+	  Unless you have an OLPC XO laptop, you will want to say N.

drivers/platform/olpc/Makefile

@@ -1,4 +1,5 @@
 #
 # OLPC XO platform-specific drivers
 #
-obj-$(CONFIG_OLPC)		+= olpc-ec.o
+obj-$(CONFIG_OLPC_EC)		+= olpc-ec.o
+obj-$(CONFIG_OLPC_XO175_EC)	+= olpc-xo175-ec.o